title: Time-dependent changes in autonomic control of splanchnic vascular resistance and heart rate in ANG II-salt hypertension.
abstract: Previous studies suggest that ANG II-induced hypertension in rats fed a high-salt (HS) diet (ANG II-salt hypertension) has a neurogenic component dependent on an enhanced sympathetic tone to the splanchnic veins and independent from changes in sympathetic nerve activity to the kidney or hind limb. The purpose of this study was to extend these findings and test whether altered autonomic control of splanchnic resistance arteries and the heart also contributes to the neurogenic component. Mean arterial pressure (MAP), heart rate (HR), superior mesenteric artery blood flow, and mesenteric vascular resistance (MVR) were measured during 4 control days, 14 days of ANG II delivered subcutaneously (150 ng·kg(-1)·min(-1)), and 4 days of recovery in conscious rats fed a HS (2% NaCl) or low-salt (LS; 0.1% NaCl) diet. Autonomic effects on MAP, HR, and MVR were assessed by acute ganglionic blockade with hexamethonium (20 mg/kg iv) on day 3 of control, days 1, 3, 5, 7, 10, and 13 of ANG II, and day 4 of recovery. MVR increased during ANG II infusion in HS and LS rats but remained elevated only in HS rats. Additionally, the MVR response to hexamethonium was enhanced on days 10 and 13 of ANG II selectively in HS rats. Compared with LS rats, HR in HS rats was higher during the 2nd wk of ANG II, and its response to hexamethonium was greater on days 7, 10, and 13 of ANG II. These results suggest that ANG II-salt hypertension is associated with delayed changes in autonomic control of splanchnic resistance arteries and the heart.
authors: Dept. of Integrative Biology and Physiology, 321 Church St. SE, Rm. 6-125 Jackson Hall, Minneapolis, MN 55455, USA.
authors: Marcos T
authors: MT
authors: Kuroki
authors: Pilar A
authors: PA
authors: Guzman
authors: Gregory D
authors: GD
authors: Fink
authors: John W
authors: JW
authors: Osborn
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D005730:Ganglionic Blockers / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D018738:Hexamethonium / Q000494:pharmacology; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D011673:Pulsatile Flow / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017673:Sodium Chloride, Dietary / Q000494:pharmacology; D013152:Splanchnic Circulation / Q000187:drug effects / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
chemical_list: D005730:Ganglionic Blockers; D017673:Sodium Chloride, Dietary; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D018738:Hexamethonium