Influence of mild sodium depletion upon peripheral and centrally mediated effects of intravenous angiotensin II in the goat.
Previous evidence for cerebral sodium/angiotensin interaction concerning centrally mediated effects of angiotensin II (AII) provided the incitement to compare in goats effects of i.v. AII during sodium repletion (SR) with those obtained during mild sodium depletion (SD). The experiments were performed in the euhydrated as well as hyperhydrated animals, and AII was infused for 10 min at 40 pmol kg-1 min-1. It was confirmed that SD is associated with elevated plasma aldosterone concentration (PA) and (as regards aldosterone secretion) a sensitization of the adrenal cortex. In contrast to PA, the plasma cortisol (PC) response to i.v. AII was significantly reduced during SD, apparently due to diminished cerebral sensitivity to circulating AII. A similar SD-associated attenuation was observed during euhydration as regards release of arginine vasopressin (AVP) in response to i.v. AII, and during hyperhydration as regards the antidiuretic effect of the octapeptide. It was confirmed that the pressor effect of i.v. AII becomes markedly reduced during SD. However, in spite of this, the associated bradycardia remained the same during SR and SD, suggesting that SD also attenuated the centrally mediated chronotropic effect of AII.
Junkergård
J
J
Department of Physiology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001826:Body Fluids / Q000502:physiology*; D005260:Female; D006041:Goats / Q000502:physiology*; D006854:Hydrocortisone / Q000097:blood; D007262:Infusions, Intravenous; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012964:Sodium / Q000172:deficiency*; D014667:Vasopressins / Q000097:blood
D014667:Vasopressins; D000804:Angiotensin II; D000450:Aldosterone; D012964:Sodium; D006854:Hydrocortisone