Recombinant adeno-associated viral (rAAV) vector-mediated overexpression of alpha-synuclein (alphaSyn) protein has been shown to cause neurodegeneration of the nigrostriatal dopaminergic pathway in rodents and primates. Using serotype-2 rAAV vectors, we recently reported the protective effect of Parkin on alphaSyn-induced nigral dopaminergic neurodegeneration in a rat model. Here we investigated the neuronal specificity of alphaSyn toxicity and the effect of Parkin co-expression in a primate model. We used another serotype (type-1) of AAV vector that was confirmed to deliver genes of interest anterogradely and retrogradely to neurons in rats. The serotype-1 rAAV (rAAV1) carrying alphaSyn cDNA (rAAV1-alphaSyn), and a cocktail of rAAV1-alphaSyn and rAAV1 carrying parkin cDNA (rAAV1-parkin) were unilaterally injected into the striatum of macaque monkeys, resulting in protein expression in striatonigral GABAergic and nigrostriatal dopaminergic neurons. Injection of rAAV1-alphaSyn alone decreased tyrosine hydroxylase immunoreactivity in the striatum compared with the contralateral side injected with a cocktail of rAAV1-alphaSyn and rAAV1-parkin. Immunostaining of striatonigral GABAergic neurons was similar on both sides. Overexpression of Parkin in GABAergic neurons was associated with less accumulation of alphaSyn protein and/or phosphorylation at Ser129 residue. Our results suggest that the toxicity of accumulated alphaSyn is not induced in non-dopaminergic neurons and that the alphaSyn-ablating effect of Parkin is exerted in virtually all neurons in primates.

Corticotropin-releasing factor (CRF) and CRF-related neuropeptides are involved in the regulation of stress-related physiology and behavior. Members of the CRF family of neuropeptides bind to two known receptors, the CRF type 1 (CRF₁) receptor, and the CRF type 2 (CRF₂) receptor. Although the distribution of CRF₂ receptor mRNA expression has been extensively studied, the distribution of CRF₂ receptor protein has not been characterized. An area of the brain known to contain high levels of CRF₂ receptor mRNA expression and CRF₂ receptor binding is the dorsal raphe nucleus (DR). In the present study we investigated in detail the distribution of CRF₂ receptor immunoreactivity throughout the rostrocaudal extent of the DR. CRF₂ receptor-immunoreactive perikarya were observed throughout the DR, with the highest number and density in the mid-rostrocaudal DR. Dual immunofluorescence revealed that CRF₂ receptor immunoreactivity was frequently co-localized with tryptophan hydroxylase, a marker of serotonergic neurons. This study provides evidence that CRF₂ receptor protein is expressed in the DR, and that CRF₂ receptors are expressed in topographically organized subpopulations of cells in the DR, including serotonergic neurons. Furthermore, these data are consistent with the hypothesis that CRF₂ receptors play an important role in the regulation of stress-related physiology and behavior through actions on serotonergic and non-serotonergic neurons within the DR.

We identified ventrolateral medullary nuclei in which thyrotropin-releasing hormone (TRH) regulates glucose metabolism by modulating autonomic activity. Immunolabeling revealed dense prepro-TRH-containing fibers innervating the rostroventrolateral medulla (RVLM) and nucleus ambiguus (Amb), which contain, respectively, pre-sympathetic motor neurons and vagal motor neurons. In anesthetized Wistar rats, microinjection of the stable TRH analog RX77368 (38-150 pmol) into the RVLM dose-dependently and site-specifically induced hyperglycemia and hyperinsulinemia. At 150 pmol, blood glucose reached a peak of 180+/-18 mg% and insulin increased 4-fold. The strongest hyperglycemic effect was induced when RX77368 was microinjected into C1 area containing adrenalin cells. Spinal cord transection at cervical-7 abolished the hyperglycemia induced by RVLM RX77368, but not the hyperinsulinemic effect. Bilateral vagotomy prevented the rise in insulin, resulting in a prolonged hyperglycemic response. The hyperglycemic and hyperinsulinemic effects of the TRH analog in the RVLM was peptide specific, since angiotensin II or a substance P analog at the same dose had weak or no effects. Microinjection of RX77368 into the Amb stimulated insulin secretion without influencing glucose levels. In conscious type 2 diabetic Goto-Kakizaki (GK) rats, intracisternal injection of RX77368 induced a remarkably amplified hyperglycemic effect with suppressed insulin response compared to Wistar rats. RX77368 microinjected into the RVLM of anesthetized GK rats induced a significantly potentiated hyperglycemic response and an impaired insulin response, compared to Wistar rats. These results indicate that the RVLM is a site at which TRH induces sympathetically-mediated hyperglycemia and vagally-mediated hyperinsulinemia, whereas the Amb is mainly a vagal activating site for TRH. Hyperinsulinemia induced by TRH in the RVLM is not secondary to the hyperglycemic response. The potentiated hyperglycemic and suppressed hyperinsulinemic responses in diabetic GK rats indicate that an unbalanced "sympathetic-over-vagal" activation by TRH in brainstem RVLM contributes to the pathophysiology of impaired glucose homeostasis in type 2 diabetes.

Central blockade of mineralocorticoid receptors (MRs) or angiotensin II type 1 receptors (AT1Rs) attenuates aldosterone (aldo)-salt induced hypertension. We examined the role of the subfornical organ (SFO), aldo synthesized locally in the brain, and MR and AT1R specifically in the paraventricular nucleus (PVN) in aldo-salt hypertension. Wistar rats were treated with subcutaneous aldo (1 μg/h) plus saline as drinking fluid, and gene expression was assessed by real-time qPCR. Other sets of rats received chronic intra-cerebroventricular (icv) infusion of aldo synthase (AS) inhibitor FAD286, MR blocker eplerenone or vehicle, electrolytic or sham lesions of the SFO, or intra-PVN infusion of AAV-MR-siRNA or AAV-AT1aR-siRNA. Infusion of aldo had no effect on 11βHSD2, MR and AT1R mRNA in different nuclei but increased CYP11B2 mRNA in the SFO, and serum and glucocorticoid-kinase 1 (Sgk1) and epithelial sodium channel (ENaC) γ subunit mRNA in the SFO and supraoptic nucleus (SON). MR-siRNA decreased both MR and AT1R mRNA in the PVN by ∼ 60%, but AT1aR-siRNA only decreased AT1R mRNA. SFO lesion, blockade of brain AS or MR, or knockdown of MR or AT1R in the PVN similarly attenuated aldosterone-induced saline intake by ∼ 50% and hypertension by ∼ 70%. These results suggest that an increase in circulating aldosterone may via MR and AT1R in the SFO increase local aldosterone production in hypothalamic nuclei such as the SON and PVN, and via MR enhance AT1R signaling in the PVN. This central aldosterone-MR-AT1R neuro-modulatory pathway appears to play a major role in the progressive hypertension.

Working memory (WM) tasks may increase or decrease the interference effect of concurrently performed cognitive control tasks. However, the neural oscillatory correlates of this modulation effect of WM on the Stroop task are still largely unknown. In the present study, behavioral and electroencephalographic (EEG) data were recorded from 32 healthy participants during their performance of the single Stroop task and the same task with a concurrent WM task. We observed that the Stroop interference effect represented in both response times (RTs) and theta-band event-related spectral perturbation (ERSP) magnitude reduced under the dual-task condition compared with the single-task condition. The reduction of interference in theta-band ERSP was further positively correlated with interference reduction in RTs, and was mainly explained by the source in the left middle frontal gyrus. In conclusion, the present study suggests that the effect of concurrent WM tasks on the reduction of the Stroop interference effect can be indexed by EEG oscillations in theta-band rhythm in the centro-frontal regions and this modulation was mediated by the reduced cognitive control under the concurrent WM task.