Ganglionic GFAP + glial Gq-GPCR signaling enhances heart functions in vivo.
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ABSTRACT: The sympathetic nervous system (SNS) accelerates heart rate, increases cardiac contractility, and constricts resistance vessels. The activity of SNS efferent nerves is generated by a complex neural network containing neurons and glia. Gq G protein-coupled receptor (Gq-GPCR) signaling in glial fibrillary acidic protein-expressing (GFAP+) glia in the central nervous system supports neuronal function and regulates neuronal activity. It is unclear how Gq-GPCR signaling in GFAP+ glia affects the activity of sympathetic neurons or contributes to SNS-regulated cardiovascular functions. In this study, we investigated whether Gq-GPCR activation in GFAP+ glia modulates the regulatory effect of the SNS on the heart; transgenic mice expressing Gq-coupled DREADD (designer receptors exclusively activated by designer drugs) (hM3Dq) selectively in GFAP+ glia were used to address this question in vivo. We found that acute Gq-GPCR activation in peripheral GFAP+ glia significantly accelerated heart rate and increased left ventricle contraction. Pharmacological experiments suggest that the glial-induced cardiac changes were due to Gq-GPCR activation in satellite glial cells within the sympathetic ganglion; this activation led to increased norepinephrine (NE) release and beta-1 adrenergic receptor activation within the heart. Chronic glial Gq-GPCR activation led to hypotension in female Gfap-hM3Dq mice. This study provides direct evidence that Gq-GPCR activation in peripheral GFAP+ glia regulates cardiovascular functions in vivo.
SUBMITTER: Xie AX
PROVIDER: S-EPMC5256145 | biostudies-literature | 2017 Jan
REPOSITORIES: biostudies-literature
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