X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Anti-Mouse IgG (H+L), made in horse antibody

RRID:AB_2313581

Antibody ID

AB_2313581

Target Antigen

IgG mouse

Proper Citation

(Vector Laboratories Cat# BA-2000, RRID:AB_2313581)

Clonality

polyclonal antibody

Comments

This record was consolidated with the Vector Laboratories Cat# BA-2000, RRID: AB_2313571 on 07/05/17

Host Organism

horse

Vendor

Vector Laboratories

Architectonic characteristics of the visual thalamus and superior colliculus in titi monkeys.

  • Baldwin MKL
  • J. Comp. Neurol.
  • 2018 Aug 1

Literature context:


Abstract:

Titi monkeys are arboreal, diurnal New World monkeys whose ancestors were the first surviving branch of the New World radiation. In the current study, we use cytoarchitectonic and immunohistochemical characteristics to compare titi monkey subcortical structures associated with visual processing with those of other well-studied primates. Our goal was to appreciate features that are similar across all New World monkeys, and primates in general, versus those features that are unique to titi monkeys and other primate taxa. We examined tissue stained for Nissl substance, cytochrome oxidase (CO), acetylcholinesterase (AChE), calbindin (Cb), parvalbumin (Pv), and vesicular glutamate transporter 2 (VGLUT2) to characterize the superior colliculus, lateral geniculate nucleus, and visual pulvinar. This is the first study to characterize VGLUT2 in multiple subcortical structures of any New World monkey. Our results from tissue processed for VGLUT2, in combination with other histological stains, revealed distinct features of subcortical structures that are similar to other primates, but also some features that are slightly modified compared to other New World monkeys and other primates. These included subdivisions of the inferior pulvinar, sublamina within the stratum griseum superficiale (SGS) of the superior colliculus, and specific koniocellular layers within the lateral geniculate nucleus. Compared to other New World primates, many features of the subcortical structures that we examined in titi monkeys were most similar to those in owl monkeys and marmosets, with the lateral geniculate nucleus consisting of two main parvocellular layers and two magnocellular layers separated by interlaminar zones or koniocellular layers.

Funding information:
  • NHLBI NIH HHS - HL27255(United States)
  • NINDS NIH HHS - F32 NS093721()
  • NINDS NIH HHS - R01 NS035103()

Thalamostriatal and cerebellothalamic pathways in a songbird, the Bengalese finch.

  • Nicholson DA
  • J. Comp. Neurol.
  • 2018 Jun 15

Literature context:


Abstract:

The thalamostriatal system is a major network in the mammalian brain, originating principally from the intralaminar nuclei of thalamus. Its functions remain unclear, but a subset of these projections provides a pathway through which the cerebellum communicates with the basal ganglia. Both the cerebellum and basal ganglia play crucial roles in motor control. Although songbirds have yielded key insights into the neural basis of vocal learning, it is unknown whether a thalamostriatal system exists in the songbird brain. Thalamic nucleus DLM is an important part of the song system, the network of nuclei required for learning and producing song. DLM receives output from song system basal ganglia nucleus Area X and sits within dorsal thalamus, the proposed avian homolog of the mammalian intralaminar nuclei that also receives projections from the cerebellar nuclei. Using a viral vector that specifically labels presynaptic axon segments, we show in Bengalese finches that dorsal thalamus projects to Area X, the basal ganglia nucleus of the song system, and to surrounding medial striatum. To identify the sources of thalamic input to Area X, we map DLM and cerebellar-recipient dorsal thalamus (DTCbN ). Surprisingly, we find both DLM and dorsal anterior DTCbN adjacent to DLM project to Area X. In contrast, the ventral medial subregion of DTCbN projects to medial striatum outside Area X. Our results suggest the basal ganglia in the song system, like the mammalian basal ganglia, integrate feedback from the thalamic region to which they project as well as thalamic regions that receive cerebellar output.

Funding information:
  • NIDCD NIH HHS - R01 DC014364()
  • NIDDK NIH HHS - U01DK089565(United States)
  • NINDS NIH HHS - R01 NS084844()

Xenobiotic Nuclear Receptor Signaling Determines Molecular Pathogenesis of Progressive Familial Intrahepatic Cholestasis.

  • Kim KH
  • Endocrinology
  • 2018 Jun 1

Literature context:


Abstract:

Progressive familial intrahepatic cholestasis (PFIC) is a genetically heterogeneous disorder of bile flow disruption due to abnormal canalicular transport or impaired bile acid (BA) metabolism, causing excess BA accumulation and liver failure. We previously reported an intrahepatic cholestasis mouse model based on loss of function of both farnesoid X receptor (FXR; NR1H4) and a small heterodimer partner (SHP; NR0B2) [double knockout (DKO)], which has strong similarities to human PFIC5. We compared the pathogenesis of DKO livers with that of another intrahepatic cholestasis model, Bsep-/-, which represents human PFIC2. Both models exhibit severe hepatomegaly and hepatic BA accumulation, but DKO showed greater circulating BA and liver injury, and Bsep-/- had milder phenotypes. Molecular profiling of BAs uncovered specific enrichment of cholic acid (CA)-derived BAs in DKO livers but chenodeoxycholate-derived BAs in Bsep-/- livers. Transcriptomic and proteomic analysis revealed specific activation of CA synthesis and alternative basolateral BA transport in DKO but increased chenodeoxycholic acid synthesis and canalicular transport in Bsep-/-. The constitutive androstane receptor (CAR)/pregnane X receptor (PXR)-CYP2B/CYP2C axis is activated in DKO livers but not in other cholestasis models. Loss of this axis in Fxr:Shp:Car:Pxr quadruple knockouts blocked Cyp2b/Cyp2c gene induction, impaired bilirubin conjugation/elimination, and increased liver injury. Differential CYP2B expression in DKO and Bsep-/- was recapitulated in human PFIC5 and PFIC2 livers. In conclusion, loss of FXR/SHP results in distinct molecular pathogenesis and CAR/PXR activation, which promotes Cyp2b/Cyp2c gene transcription and bilirubin clearance. CAR/PXR activation was not observed in Bsep-/- mice or PFIC2 patients. These findings provide a deeper understanding of the heterogeneity of intrahepatic cholestasis.

Funding information:
  • NHLBI NIH HHS - R01 HL064888(United States)

G-Protein-Coupled Receptor Gpr17 Expression in Two Multiple Sclerosis Remyelination Models.

  • Nyamoya S
  • Mol. Neurobiol.
  • 2018 Jun 5

Literature context:


Abstract:

In multiple sclerosis patients, demyelination is prominent in both the white and gray matter. Chronic clinical deficits are known to result from acute or chronic injury to the myelin sheath and inadequate remyelination. The underlying molecular mechanisms of remyelination and its failure remain currently unclear. Recent studies have recognized G protein-coupled receptor 17 (GPR17) as an important regulator of oligodendrocyte development and remyelination. So far, the relevance of GPR17 for myelin repair was mainly tested in remyelinating white matter lesions. The relevance of GPR17 for gray matter remyelination as well as remyelination of chronic white matter lesions was not addressed so far. Here, we provide a detailed characterization of GPR17 expression during experimental de- and remyelination. Experimental lesions with robust and limited endogenous remyelination capacity were established by either acute or chronic cuprizone-induced demyelination. Furthermore, remyelinating lesions were induced by the focal injection of lysophosphatidylcholine (LPC) into the corpus callosum. GPR17 expression was analyzed by complementary techniques including immunohistochemistry, in situ hybridization, and real-time PCR. In control animals, GPR17+ cells were evenly distributed in the corpus callosum and cortex and displayed a highly ramified morphology. Virtually all GPR17+ cells also expressed the oligodendrocyte-specific transcription factor OLIG2. After acute cuprizone-induced demyelination, robust endogenous remyelination was evident in the white matter corpus callosum but not in the gray matter cortex. Endogenous callosal remyelination was paralleled by a robust induction of GPR17 expression which was absent in the gray matter cortex. Higher numbers of GPR17+ cells were as well observed after LPC-induced focal white matter demyelination. In contrast, densities of GPR17+ cells were comparable to control animals after chronic cuprizone-induced demyelination indicating quiescence of this cell population. Our findings demonstrate that GPR17 expression induction correlates with acute demyelination and sufficient endogenous remyelination. This strengthens the view that manipulation of this receptor might be a therapeutic opportunity to support endogenous remyelination.

Funding information:
  • Deutsche Forschungsgemeinschaft - KI 1469/8-1()
  • NIGMS NIH HHS - R01 GM085490-03(United States)

Localization of the cannabinoid type-1 receptor in subcellular astrocyte compartments of mutant mouse hippocampus.

  • Gutiérrez-Rodríguez A
  • Glia
  • 2018 Feb 27

Literature context:


Abstract:

Astroglial type-1 cannabinoid (CB1 ) receptors are involved in synaptic transmission, plasticity and behavior by interfering with the so-called tripartite synapse formed by pre- and post-synaptic neuronal elements and surrounding astrocyte processes. However, little is known concerning the subcellular distribution of astroglial CB1 receptors. In particular, brain CB1 receptors are mostly localized at cells' plasmalemma, but recent evidence indicates their functional presence in mitochondrial membranes. Whether CB1 receptors are present in astroglial mitochondria has remained unknown. To investigate this issue, we included conditional knock-out mice lacking astroglial CB1 receptor expression specifically in glial fibrillary acidic protein (GFAP)-containing astrocytes (GFAP-CB1 -KO mice) and also generated genetic rescue mice to re-express CB1 receptors exclusively in astrocytes (GFAP-CB1 -RS). To better identify astroglial structures by immunoelectron microscopy, global CB1 knock-out (CB1 -KO) mice and wild-type (CB1 -WT) littermates were intra-hippocampally injected with an adeno-associated virus expressing humanized renilla green fluorescent protein (hrGFP) under the control of human GFAP promoter to generate GFAPhrGFP-CB1 -KO and -WT mice, respectively. Furthermore, double immunogold (for CB1 ) and immunoperoxidase (for GFAP or hrGFP) revealed that CB1 receptors are present in astroglial mitochondria from different hippocampal regions of CB1 -WT, GFAP-CB1 -RS and GFAPhrGFP-CB1 -WT mice. Only non-specific gold particles were detected in mouse hippocampi lacking CB1 receptors. Altogether, we demonstrated the existence of a precise molecular architecture of the CB1 receptor in astrocytes that will have to be taken into account in evaluating the functional activity of cannabinergic signaling at the tripartite synapse.

Funding information:
  • NCI NIH HHS - R01 CA105304-06A1(United States)

mTORC1/rpS6 regulates blood-testis barrier dynamics and spermatogenetic function in the testis in vivo.

  • Li SYT
  • Am. J. Physiol. Endocrinol. Metab.
  • 2018 Feb 1

Literature context:


Abstract:

The blood-testis barrier (BTB), conferred by Sertoli cells in the mammalian testis, is an important ultrastructure that supports spermatogenesis. Studies using animal models have shown that a disruption of the BTB leads to meiotic arrest, causing defects in spermatogenesis and male infertility. To better understand the regulation of BTB dynamics, we report findings herein to understand the role of ribosomal protein S6 (rpS6), a downstream signaling protein of mammalian target of rapamycin complex 1 (mTORC1), in promoting BTB disruption in the testis in vivo, making the barrier "leaky." Overexpression of wild-type rpS6 (rpS6-WT, the full-length cDNA cloned into the mammalian expression vector pCI-neo) and a constitutively active quadruple phosphomimetic mutant cloned into pCI-neo (p-rpS6-MT) vs. control (empty pCI-neo vector) was achieved by transfecting adult rat testes with the corresponding plasmid DNA using a Polyplus in vivo-jetPEI transfection reagent. On the basis of an in vivo functional BTB integrity assay, p-rpS6-MT was found to induce BTB disruption better than rpS6-WT did (and no effects in empty vector control), leading to defects in spermatogenesis, including loss of spermatid polarity and failure in the transport of cells (e.g., spermatids) and organelles (e.g., phagosomes), to be followed by germ exfoliation. More important, rpS6-WT and p-rpS6-MT exert their disruptive effects through changes in the organization of actin- and microtubule (MT)-based cytoskeletons, which are mediated by changes in the spatiotemporal expression of actin- and MT-based binding and regulatory proteins. In short, mTORC1/rpS6 signaling complex is a regulator of spermatogenesis and BTB by modulating the organization of the actin- and MT-based cytoskeletons.

Funding information:
  • Canadian Institutes of Health Research - (Canada)
  • NICHD NIH HHS - R01 HD056034()

Architectonic features and relative locations of primary sensory and related areas of neocortex in mouse lemurs.

  • Saraf MP
  • J. Comp. Neurol.
  • 2018 Feb 26

Literature context:


Abstract:

Mouse lemurs are the smallest of the living primates, and are members of the understudied radiation of strepsirrhine lemurs of Madagascar. They are thought to closely resemble the ancestral primates that gave rise to present day primates. Here we have used multiple histological and immunochemical methods to identify and characterize sensory areas of neocortex in four brains of adult lemurs obtained from a licensed breeding colony. We describe the laminar features for the primary visual area (V1), the secondary visual area (V2), the middle temporal visual area (MT) and area prostriata, somatosensory areas S1(3b), 3a, and area 1, the primary motor cortex (M1), and the primary auditory cortex (A1). V1 has "blobs" with "nonblob" surrounds, providing further evidence that this type of modular organization might have evolved early in the primate lineage to be retained in all extant primates. The laminar organization of V1 further supports the view that sublayers of layer 3 of primates have been commonly misidentified as sublayers of layer 4. S1 (area 3b) is proportionately wider than the elongated area observed in anthropoid primates, and has disruptions that may distinguish representations of the hand, face, teeth, and tongue. Primary auditory cortex is located in the upper temporal cortex and may include a rostral area, R, in addition to A1. The resulting architectonic maps of cortical areas in mouse lemurs can usefully guide future studies of cortical connectivity and function.

Funding information:
  • NCI NIH HHS - T32-CA09151(United States)
  • NEI NIH HHS - R01 EY002686()
  • NEI NIH HHS - R01 EY025422()

Actin nucleator Spire 1 is a regulator of ectoplasmic specialization in the testis.

  • Wen Q
  • Cell Death Dis
  • 2018 Feb 12

Literature context:


Abstract:

Germ cell differentiation during the epithelial cycle of spermatogenesis is accompanied by extensive remodeling at the Sertoli cell-cell and Sertoli cell-spermatid interface to accommodate the transport of preleptotene spermatocytes and developing spermatids across the blood-testis barrier (BTB) and the adluminal compartment of the seminiferous epithelium, respectively. The unique cell junction in the testis is the actin-rich ectoplasmic specialization (ES) designated basal ES at the Sertoli cell-cell interface, and the apical ES at the Sertoli-spermatid interface. Since ES dynamics (i.e., disassembly, reassembly and stabilization) are supported by actin microfilaments, which rapidly converts between their bundled and unbundled/branched configuration to confer plasticity to the ES, it is logical to speculate that actin nucleation proteins play a crucial role to ES dynamics. Herein, we reported findings that Spire 1, an actin nucleator known to polymerize actins into long stretches of linear microfilaments in cells, is an important regulator of ES dynamics. Its knockdown by RNAi in Sertoli cells cultured in vitro was found to impede the Sertoli cell tight junction (TJ)-permeability barrier through changes in the organization of F-actin across Sertoli cell cytosol. Unexpectedly, Spire 1 knockdown also perturbed microtubule (MT) organization in Sertoli cells cultured in vitro. Biochemical studies using cultured Sertoli cells and specific F-actin vs. MT polymerization assays supported the notion that a transient loss of Spire 1 by RNAi disrupted Sertoli cell actin and MT polymerization and bundling activities. These findings in vitro were reproduced in studies in vivo by RNAi using Spire 1-specific siRNA duplexes to transfect testes with Polyplus in vivo-jetPEI as a transfection medium with high transfection efficiency. Spire 1 knockdown in the testis led to gross disruption of F-actin and MT organization across the seminiferous epithelium, thereby impeding the transport of spermatids and phagosomes across the epithelium and perturbing spermatogenesis. In summary, Spire 1 is an ES regulator to support germ cell development during spermatogenesis.

Funding information:
  • NICHD NIH HHS - HD007520(United States)

Systematic Morphometry of Catecholamine Nuclei in the Brainstem.

  • Bucci D
  • Front Neuroanat
  • 2017 Nov 23

Literature context:


Abstract:

Catecholamine nuclei within the brainstem reticular formation (RF) play a pivotal role in a variety of brain functions. However, a systematic characterization of these nuclei in the very same experimental conditions is missing so far. Tyrosine hydroxylase (TH) immune-positive cells of the brainstem correspond to dopamine (DA)-, norepinephrine (NE)-, and epinephrine (E)-containing cells. Here, we report a systematic count of TH-positive neurons in the RF of the mouse brainstem by using stereological morphometry. All these nuclei were analyzed for anatomical localization, rostro-caudal extension, volume, neuron number, neuron density, and mean neuronal area for each nucleus. The present data apart from inherent informative value wish to represent a reference for neuronal mapping in those studies investigating the functional anatomy of the brainstem RF. These include: the sleep-wake cycle, movement control, muscle tone modulation, mood control, novelty orienting stimuli, attention, archaic responses to internal and external stressful stimuli, anxiety, breathing, blood pressure, and innumerable activities modulated by the archaic iso-dendritic hard core of the brainstem RF. Most TH-immune-positive cells fill the lateral part of the RF, which indeed possesses a high catecholamine content. A few nuclei are medial, although conventional nosography considers all these nuclei as part of the lateral column of the RF. Despite the key role of these nuclei in psychiatric and neurological disorders, only a few of them aspired a great attention in biomedical investigation, while most of them remain largely obscure although intense research is currently in progress. A simultaneous description of all these nuclei is not simply key to comprehend the variety of brainstem catecholamine reticular neurons, but probably represents an intrinsically key base for understanding brain physiology and physiopathology.

Different Forms of AMPA Receptor Mediated LTP and Their Correlation to the Spatial Working Memory Formation.

  • Shimshek DR
  • Front Mol Neurosci
  • 2017 Jul 20

Literature context:


Abstract:

Spatial working memory (SWM) and the classical, tetanus-induced long-term potentiation (LTP) at hippocampal CA3/CA1 synapses are dependent on L-α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors (AMPARs) containing GluA1 subunits as demonstrated by knockout mice lacking GluA1. In GluA1 knockout mice LTP and SWM deficits could be partially recovered by transgenic re-installation of full-length GluA1 in principle forebrain neurons. Here we partially restored hippocampal LTP in GluA1-deficient mice by forebrain-specific depletion of the GluA2 gene, by the activation of a hypomorphic GluA2(Q) allele and by transgenic expression of PDZ-site truncated GFP-GluA1(TG). In none of these three mouse lines, the partial LTP recovery improved the SWM performance of GluA1-deficient mice suggesting a specific function of intact GluA1/2 receptors and the GluA1 intracellular carboxyl-terminus in SWM and its associated behavior.

Epidermal growth factor signals attenuate phenotypic and functional development of neocortical GABA neurons.

  • Namba H
  • J. Neurochem.
  • 2017 Jun 13

Literature context:


Abstract:

Phenotypic development of neocortical GABA neurons is highly plastic and promoted by various neurotrophic factors such as neuregulin-1. A subpopulation of GABA neurons expresses not only neuregulin receptor (ErbB4) but also epidermal growth factor (EGF) receptor (ErbB1) during development, but the neurobiological action of EGF on this cell population is less understood than that of neuregulin-1. Here, we examined the effects of exogenous EGF on immature GABA neurons both in culture and in vivo and also explored physiological consequences in adults. We prepared low density cultures from the neocortex of rat embryos and treated neocortical neurons with EGF. EGF decreased protein levels of glutamic acid decarboxylases (GAD65 and GAD67), and EGF influences on neuronal survival and glial proliferation were negligible or limited. The EGF treatment also diminished the frequency of miniature inhibitory postsynaptic currents (mIPSCs). In vivo administration of EGF to mouse pups reproduced the above GABAergic phenomena in neocortical culture. In EGF-injected postnatal mice, GAD- and parvalbumin-immunoreactivities were reduced in the frontal cortex. In addition, postnatal EGF treatment decreased mIPSC frequency in, and the density of, GABAergic terminals on pyramidal cells. Although these phenotypic influences on GABA neurons became less marked during development, it later resulted in the reduced β- and γ-powers of sound-evoked electroencephalogram in adults, which is regulated by parvalbumin-positive GABA neurons and implicated in the schizophrenia pathophysiology. These findings suggest that, in contrast to the ErbB4 ligand of neuregulin-1, the ErbB1 ligand of EGF exerts unique maturation-attenuating influences on developing cortical GABAergic neurons.

Funding information:
  • Wellcome Trust - 090108/Z/09/Z(United Kingdom)

Optic nerve, superior colliculus, visual thalamus, and primary visual cortex of the northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus).

  • Turner EC
  • J. Comp. Neurol.
  • 2017 Jun 15

Literature context:


Abstract:

The northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus) are members of a diverse clade of carnivorous mammals known as pinnipeds. Pinnipeds are notable for their large, ape-sized brains, yet little is known about their central nervous system. Both the northern elephant seal and California sea lion spend most of their lives at sea, but each also spends time on land to breed and give birth. These unique coastal niches may be reflected in specific evolutionary adaptations to their sensory systems. Here, we report on components of the visual pathway in these two species. We found evidence for two classes of myelinated fibers within the pinniped optic nerve, those with thick myelin sheaths (elephant seal: 9%, sea lion: 7%) and thin myelin sheaths (elephant seal: 91%, sea lion: 93%). In order to investigate the architecture of the lateral geniculate nucleus, superior colliculus, and primary visual cortex, we processed brain sections from seal and sea lion pups for Nissl substance, cytochrome oxidase, and vesicular glutamate transporters. As in other carnivores, the dorsal lateral geniculate nucleus consisted of three main layers, A, A1, and C, while each superior colliculus similarly consisted of seven distinct layers. The sea lion visual cortex is located at the posterior side of cortex between the upper and lower banks of the postlateral sulcus, while the elephant seal visual cortex extends far more anteriorly along the dorsal surface and medial wall. These results are relevant to comparative studies related to the evolution of large brains.

Spatial distribution of synapses on tyrosine hydroxylase-expressing juxtaglomerular cells in the mouse olfactory glomerulus.

  • Kiyokage E
  • J. Comp. Neurol.
  • 2017 Apr 1

Literature context:


Abstract:

Olfactory sensory axons converge in specific glomeruli where they form excitatory synapses onto dendrites of mitral/tufted (M/T) and juxtaglomerular (JG) cells, including periglomerular (PG), external tufted (ET), and superficial-short axon cells. JG cells consist of heterogeneous subpopulations with different neurochemical, physiological, and morphological properties. Among JG cells, previous electron microscopic (EM) studies have shown that the majority of synaptic inputs to tyrosine hydroxylase (TH)-immunoreactive neurons were asymmetrical synapses from olfactory nerve (ON) terminals. However, recent physiological results revealed that 70% of dopaminergic/γ-aminobutyric acid (GABA)ergic neurons received polysynaptic inputs via ET cells, whereas the remaining 30% received monosynaptic ON inputs. To understand the discrepancies between EM and physiological data, we used serial EM analysis combined with confocal laser scanning microscope images to examine the spatial distribution of synapses on dendrites using mice expressing enhanced green fluorescent protein under the control of the TH promoter. The majority of synaptic inputs to TH-expressing JG cells were from ON terminals, and they preferentially targeted distal dendrites from the soma. On the other hand, the numbers of non-ON inputs were fewer and targeted proximal dendrites. Furthermore, individual TH-expressing JG cells formed serial synapses, such as M/T→TH→another presumed M/T or ON→TH→presumed M/T, but not reciprocal synapses. Serotonergic fibers also associated with somatic regions of TH neurons, displaying non-ON profiles. Thus, fewer proximal non-ON synapses provide more effective inputs than large numbers of distal ON synapses and may occur on the physiologically characterized population of dopaminergic-GABAergic neurons (70%) that receive their most effective inputs indirectly via an ON→ET→TH circuit. J. Comp. Neurol. 525:1059-1074, 2017. © 2017 Wiley Periodicals, Inc.

Funding information:
  • NIMH NIH HHS - R01 MH066332(United States)
  • NINDS NIH HHS - NS067017(United States)

Acute Inactivation of Primary Auditory Cortex Causes a Sound Localisation Deficit in Ferrets.

  • Wood KC
  • PLoS ONE
  • 2017 Jan 18

Literature context:


Abstract:

The objective of this study was to demonstrate the efficacy of acute inactivation of brain areas by cooling in the behaving ferret and to demonstrate that cooling auditory cortex produced a localisation deficit that was specific to auditory stimuli. The effect of cooling on neural activity was measured in anesthetized ferret cortex. The behavioural effect of cooling was determined in a benchmark sound localisation task in which inactivation of primary auditory cortex (A1) is known to impair performance. Cooling strongly suppressed the spontaneous and stimulus-evoked firing rates of cortical neurons when the cooling loop was held at temperatures below 10°C, and this suppression was reversed when the cortical temperature recovered. Cooling of ferret auditory cortex during behavioural testing impaired sound localisation performance, with unilateral cooling producing selective deficits in the hemifield contralateral to cooling, and bilateral cooling producing deficits on both sides of space. The deficit in sound localisation induced by inactivation of A1 was not caused by motivational or locomotor changes since inactivation of A1 did not affect localisation of visual stimuli in the same context.

Funding information:
  • Biotechnology and Biological Sciences Research Council - BB/H016813/1()

Somatosensory brainstem, thalamus, and cortex of the California sea lion (Zalophus californianus).

  • Sawyer EK
  • J. Comp. Neurol.
  • 2016 Jun 15

Literature context:


Abstract:

Pinnipeds (sea lions, seals, and walruses) are notable for many reasons, including their ape-sized brains, their adaptation to a coastal niche that combines mastery of the sea with strong ties to land, and the remarkable abilities of their trigeminal whisker system. However, little is known about the central nervous system of pinnipeds. Here we report on the somatosensory areas of the nervous system of the California sea lion (Zalophus californianus). Using stains for Nissl, cytochrome oxidase, and vesicular glutamate transporters, we investigated the primary somatosensory areas in the brainstem, thalamus, and cortex in one sea lion pup and the external anatomy of the brain in a second pup. We find that the sea lion's impressive array of whiskers is matched by a large trigeminal representation in the brainstem with well-defined parcellation that resembles the barrelettes found in rodents but scaled upward in size. The dorsal column nuclei are large and distinct. The ventral posterior nucleus of the thalamus has divisions, with a large area for the presumptive head representation. Primary somatosensory cortex is located in the neocortex just anterior to the main vertical fissure, and precisely locating it as we do here is useful for comparing the highly gyrified pinniped cortex with that of other carnivores. To our knowledge this work is the first comprehensive report on the central nervous system areas for any sensory system in a pinniped. The results may be useful both in the veterinary setting and for comparative studies related to brain evolution.

Cortico-Cortical Connectivity Within Ferret Auditory Cortex.

  • Bizley JK
  • J. Comp. Neurol.
  • 2015 Oct 15

Literature context:


Abstract:

Despite numerous studies of auditory cortical processing in the ferret (Mustela putorius), very little is known about the connections between the different regions of the auditory cortex that have been characterized cytoarchitectonically and physiologically. We examined the distribution of retrograde and anterograde labeling after injecting tracers into one or more regions of ferret auditory cortex. Injections of different tracers at frequency-matched locations in the core areas, the primary auditory cortex (A1) and anterior auditory field (AAF), of the same animal revealed the presence of reciprocal connections with overlapping projections to and from discrete regions within the posterior pseudosylvian and suprasylvian fields (PPF and PSF), suggesting that these connections are frequency specific. In contrast, projections from the primary areas to the anterior dorsal field (ADF) on the anterior ectosylvian gyrus were scattered and non-overlapping, consistent with the non-tonotopic organization of this field. The relative strength of the projections originating in each of the primary fields differed, with A1 predominantly targeting the posterior bank fields PPF and PSF, which in turn project to the ventral posterior field, whereas AAF projects more heavily to the ADF, which then projects to the anteroventral field and the pseudosylvian sulcal cortex. These findings suggest that parallel anterior and posterior processing networks may exist, although the connections between different areas often overlap and interactions were present at all levels.

Distributions of vesicular glutamate transporters 1 and 2 in the visual system of tree shrews (Tupaia belangeri).

  • Balaram P
  • J. Comp. Neurol.
  • 2015 Aug 15

Literature context:


Abstract:

Vesicular glutamate transporter (VGLUT) proteins regulate the storage and release of glutamate from synapses of excitatory neurons. Two isoforms, VGLUT1 and VGLUT2, are found in most glutamatergic projections across the mammalian visual system, and appear to differentially identify subsets of excitatory projections between visual structures. To expand current knowledge on the distribution of VGLUT isoforms in highly visual mammals, we examined the mRNA and protein expression patterns of VGLUT1 and VGLUT2 in the lateral geniculate nucleus (LGN), superior colliculus, pulvinar complex, and primary visual cortex (V1) in tree shrews (Tupaia belangeri), which are closely related to primates but classified as a separate order (Scandentia). We found that VGLUT1 was distributed in intrinsic and corticothalamic connections, whereas VGLUT2 was predominantly distributed in subcortical and thalamocortical connections. VGLUT1 and VGLUT2 were coexpressed in the LGN and in the pulvinar complex, as well as in restricted layers of V1, suggesting a greater heterogeneity in the range of efferent glutamatergic projections from these structures. These findings provide further evidence that VGLUT1 and VGLUT2 identify distinct populations of excitatory neurons in visual brain structures across mammals. Observed variations in individual projections may highlight the evolution of these connections through the mammalian lineage.

Funding information:
  • NIDDK NIH HHS - R01 DK046367(United States)

Saccadic Palsy following Cardiac Surgery: Possible Role of Perineuronal Nets.

  • Eggers SD
  • PLoS ONE
  • 2015 Jul 3

Literature context:


Abstract:

OBJECTIVE: Perineuronal nets (PN) form a specialized extracellular matrix around certain highly active neurons within the central nervous system and may help to stabilize synaptic contacts, promote local ion homeostasis, or play a protective role. Within the ocular motor system, excitatory burst neurons and omnipause neurons are highly active cells that generate rapid eye movements - saccades; both groups of neurons contain the calcium-binding protein parvalbumin and are ensheathed by PN. Experimental lesions of excitatory burst neurons and omnipause neurons cause slowing or complete loss of saccades. Selective palsy of saccades in humans is reported following cardiac surgery, but such cases have shown normal brainstem neuroimaging, with only one clinicopathological study that demonstrated paramedian pontine infarction. Our objective was to test the hypothesis that lesions of PN surrounding these brainstem saccade-related neurons may cause saccadic palsy. METHODS: Together with four controls we studied the brain of a patient who had developed a permanent selective saccadic palsy following cardiac surgery and died several years later. Sections of formalin-fixed paraffin-embedded brainstem blocks were applied to double-immunoperoxidase staining of parvalbumin and three different components of PN. Triple immunofluorescence labeling for all PN components served as internal controls. Combined immunostaining of parvalbumin and synaptophysin revealed the presence of synapses. RESULTS: Excitatory burst neurons and omnipause neurons were preserved and still received synaptic input, but their surrounding PN showed severe loss or fragmentation. INTERPRETATION: Our findings support current models and experimental studies of the brainstem saccade-generating neurons and indicate that damage to PN may permanently impair the function of these neurons that the PN ensheathe. How a postulated hypoxic mechanism could selectively damage the PN remains unclear. We propose that the well-studied saccadic eye movement system provides an accessible model to evaluate the role of PN in health and disease.

Funding information:
  • NINDS NIH HHS - 4R00NS057944-03(United States)

The isthmic nuclei providing parallel feedback connections to the avian tectum have different neurochemical identities: Expression of glutamatergic and cholinergic markers in the chick (Gallus gallus).

  • González-Cabrera C
  • J. Comp. Neurol.
  • 2015 Jun 15

Literature context:


Abstract:

Retinal inputs to the optic tectum (TeO) triggered by moving stimuli elicit synchronized feedback signals from two isthmic nuclei: the isthmi parvocelullaris (Ipc) and isthmi semilunaris (SLu). Both of these nuclei send columnar axon terminals back to the same tectal position receiving the retinal input. The feedback signals from the Ipc seem to act as an attentional spotlight by selectively boosting the propagation of retinal inputs from the tectum to higher visual areas. Although Ipc and SLu nuclei are widely considered cholinergic because of their immunoreactivity for choline acetyltransferase (ChAT), contradictory findings, including the expression of the vesicular glutamate transporter 2 (VGluT2) mRNA in Ipc neurons, have raised doubts about the purely cholinergic nature of this nucleus. In this study, in chicks, we revise the neurochemical identity of the isthmic nuclei by using in situ hybridization assays for VGluT2 along with three cholinergic markers: the vesicular acetylcholine transporter (VAChT), the high-affinity choline transporter (CHT1) and ChAT. We found that neurons in the SLu showed strong mRNA expression of all three cholinergic markers, whereas the expression of VAChT mRNA in the Ipc was undetectable in our essays. Instead, Ipc neurons exhibited a strong expression of VGluT2 mRNA. Immunohistochemistry assays showed VGluT2 immunoreactivity in the TeO codistributing with anterogradely labeled Ipc axon-terminal boutons, further supporting a glutamatergic function for the Ipc nucleus. Therefore, our results strongly suggest that, in the chick, whereas the feedback from the SLu to the TeO is indeed cholinergic, the feedback from the Ipc has a marked glutamatergic component.

Funding information:
  • NIDCD NIH HHS - R01 DC012957(United States)

Localization of α-synuclein in teleost central nervous system: immunohistochemical and Western blot evidence by 3D5 monoclonal antibody in the common carp, Cyprinus carpio.

  • Vaccaro R
  • J. Comp. Neurol.
  • 2015 May 1

Literature context:


Abstract:

Alpha synuclein (α-syn) is a 140 amino acid vertebrate-specific protein, highly expressed in the human nervous system and abnormally accumulated in Parkinson's disease and other neurodegenerative disorders, known as synucleinopathies. The common occurrence of α-syn aggregates suggested a role for α-syn in these disorders, although its biological activity remains poorly understood. Given the high degree of sequence similarity between vertebrate α-syns, we investigated this proteins in the central nervous system (CNS) of the common carp, Cyprinus carpio, with the aim of comparing its anatomical and cellular distribution with that of mammalian α-syn. The distribution of α-syn was analyzed by semiquantitative western blot, immunohistochemistry, and immunofluorescence by a novel monoclonal antibody (3D5) against a fully conserved epitope between carp and human α-syn. The distribution of 3D5 immunoreactivity was also compared with that of choline acetyltransferase (ChAT), tyrosine hydroxylase (TH), and serotonin (5HT) by double immunolabelings. The results showed that a α-syn-like protein of about 17 kDa is expressed to different levels in several brain regions and in the spinal cord. Immunoreactive materials were localized in neuronal perikarya and varicose fibers but not in the nucleus. The present findings indicate that α-syn-like proteins may be expressed in a few subpopulations of catecholaminergic and serotoninergic neurons in the carp brain. However, evidence of cellular colocalization 3D5/TH or 3D5/5HT was rare. Differently, the same proteins appear to be coexpressed with ChAT by cholinergic neurons in several motor and reticular nuclei. These results sustain the functional conservation of the α-syn expression in cholinergic systems and suggest that α-syn modulates similar molecular pathways in phylogenetically distant vertebrates.

Structural basis for serotonergic regulation of neural circuits in the mouse olfactory bulb.

  • Suzuki Y
  • J. Comp. Neurol.
  • 2015 Feb 1

Literature context:


Abstract:

Olfactory processing is well known to be regulated by centrifugal afferents from other brain regions, such as noradrenergic, acetylcholinergic, and serotonergic neurons. Serotonergic neurons widely innervate and regulate the functions of various brain regions. In the present study, we focused on serotonergic regulation of the olfactory bulb (OB), one of the most structurally and functionally well-defined brain regions. Visualization of a single neuron among abundant and dense fibers is essential to characterize and understand neuronal circuits. We accomplished this visualization by successfully labeling and reconstructing serotonin (5-hydroxytryptamine: 5-HT) neurons by infection with sindbis and adeno-associated virus into dorsal raphe nuclei (DRN) of mice. 5-HT synapses were analyzed by correlative confocal laser microscopy and serial-electron microscopy (EM) study. To further characterize 5-HT neuronal and network function, we analyzed whether glutamate was released from 5-HT synaptic terminals using immuno-EM. Our results are the first visualizations of complete 5-HT neurons and fibers projecting from DRN to the OB with bifurcations. We found that a single 5-HT axon can form synaptic contacts to both type 1 and 2 periglomerular cells within a single glomerulus. Through immunolabeling, we also identified vesicular glutamate transporter 3 in 5-HT neurons terminals, indicating possible glutamatergic transmission. Our present study strongly implicates the involvement of brain regions such as the DRN in regulation of the elaborate mechanisms of olfactory processing. We further provide a structure basis of the network for coordinating or linking olfactory encoding with other neural systems, with special attention to serotonergic regulation.

Funding information:
  • NEI NIH HHS - EY020826(United States)