title: Angiotensin II in the paraventricular nucleus stimulates sympathetic outflow to the cardiovascular system and make vasopressin release in rat.
abstract: The hypothalamic paraventricular nucleus (PVN) plays essential roles in neuroendocrine and autonomic functions, including cardiovascular regulation. It was shown that microinjection of angiotensin II (AngII) into the PVN produced a pressor response. In this study, we explored the probable mechanisms of this pressor response. AngII was microinjected into the PVN and cardiovascular responses were recorded. Then, the responses were re-tested after systemic injection of a ganglionic blocker, Hexamethonium, or a vasopressin V1 receptor blocker. Hexamethonium pretreatment (i.v.) greatly and significantly attenuated the pressor response to AngII, with no significant effect on heart rate, indicating that the sympathetic system is involved in the cardiovascular effect of AngII in the PVN. Systemic pretreatment (i.v.) with V1 antagonist greatly and significantly attenuated the pressor response to AngII, with no significant effect on heart rate, indicating that vasopressin release is involved in the cardiovascular effect of AngII in the PVN. Overall, we found that AngII microinjected into the PVN produced a pressor response mediated by the sympathetic system and vasopressin release, indicating that other than circulating AngII, endogenous AngII of the PVN increases the vasopressin release from the PVN.
authors: Department of physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors: Mehrangiz
authors: M
authors: Khanmoradi
authors: Department of physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Electronic address: nasimi@med.mui.ac.ir.
authors: Ali
authors: A
authors: Nasimi
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects* / Q000378:metabolism; D005730:Ganglionic Blockers / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D018738:Hexamethonium / Q000494:pharmacology; D008297:Male; D008845:Microinjections; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000378:metabolism; D014667:Vasopressins / Q000378:metabolism*
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D005730:Ganglionic Blockers; D014667:Vasopressins; D000804:Angiotensin II; D018738:Hexamethonium
keywords: Angiotensin II; Arterial pressure; Hexamethonium; PVN; Paraventricular nucleus; Vasopressin