α-Adrenoceptor Subtype in the Hypothalamic Paraventricular Nucleus Involved in the Regulation of Urine Production: Comparison between Wistar Kyoto and Spontaneously Hypertensive Rats

[摘要] References(14)Cited-By(1)Microinjections of α-adrenoceptor agonists into the paraventricular nucleus (PVN)of Wistar Kyoto rats (WKY)decreased the urine outflow rate in dose and time-dependent manners. The order of the antidiuretic potency is norepinephrine (an α-agonist)> phenylephrine (an α1-agonist)>> clonidine (an α2-agonist). The phenylephrine-induced effect was inhibited by WB4101 (an α1-antagonist), but not by yohimbine (an α2-antagonist). d(CH2)5-D-Tyr(Et)VAVP (a vasopressin antagonist)blocked the antidiuretic effect of phenylephrine. In spontaneously hypertensive rats (SHR), norepinephrine and phenylephrine produced weaker antidiuretic effects than in WKY. These findings suggest that the α1-subtype of the PVN decreases urine production mediated through vasopressin release. This mechanism is more feeble in SHR than WKY.

[学科分类] 药理学

[关键词] α1-Adrenoceptor;Paraventricular nucleus;Vasopressin