title: Alpha 2-adrenergic stimulation within the nucleus tractus solitarius attenuates vasopressin release induced by depletion of cardiovascular volume.
abstract: The functional role of the nucleus tractus solitarius (NTS) in the regulation of arginine-vasopressin (AVP) release mediated by baroreceptor activation was investigated by examining the effects induced by the presynaptic alpha-adrenergic agonist clonidine. The present data show that microinjection of clonidine into NTS resulted in a significant attenuation of AVP secretion induced by hypovolemia in the rat. This effect produced by NTS injection of 8 and 10 nmol clonidine was prevented by NTS pretreatment with the alpha 2-adrenoceptor blocker, yohimbine (10 nmol), indicating alpha 2-adrenergic receptors were required for the biological response. These findings suggest that catecholaminergic projections from NTS to hypothalamic vasopressinergic neurons play a facilitatory role in controlling AVP secretion.
authors.affiliation: Department of Neurology, 2nd Medical School, University of Naples, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Iovino
authors.forename: A
authors.initials: A
authors.lastname: Vanacore
authors.forename: L
authors.initials: L
authors.lastname: Steardo
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood; D001810:Blood Volume / Q000502:physiology*; D003000:Clonidine / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D008845:Microinjections; D011092:Polyethylene Glycols / Q000494:pharmacology; D011311:Pressoreceptors / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex / Q000187:drug effects; D014667:Vasopressins / Q000378:metabolism*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D014667:Vasopressins; D001127:Arginine Vasopressin; D015016:Yohimbine; D011092:Polyethylene Glycols; D003000:Clonidine