Effects of paraventricular nucleus lesions on chronic renal hypertension.
The contribution of the paraventricular nucleus region of the hypothalamus (PVN) to the maintenance of one-kidney, figure-8 renal wrap hypertension was determined in this study. Electrolytic ablation of the PVN was performed 4 wk after the production of hypertension or sham operation. Ablation of the PVN region significantly reduced mean arterial pressure (MAP) from 150 +/- 9 to 110 +/- 3 mmHg in the hypertensive rats. In the sham-hypertensive group, the lesion decreased MAP from 118 +/- 2 to 99 +/- 4 mmHg. In both groups of animals MAP from 118 +/- 2 to 99 +/- 4 mmHg. In both groups of animals MAP returned to prelesion values by day 7 postlesion. When ganglionic blockade was performed on day 7 postlesion, the fall in MAP was greater in hypertensive rats (-44 +/- 5 mmHg) than in normotensive rats (-26 +/- 3 mmHg). In a separate group of rats studied 3 days after PVN ablation, ganglionic blockade produced similar decreases in MAP in the wrapped and sham-operated animals. These studies suggest that the PVN contributes to the increased functional sympathetic nervous system associated with one-kidney, figure-8 renal hypertension. Although ablation of the PVN region decreases MAP, neural mechanisms compensate to return MAP to hypertensive levels.
Herzig
T C
TC
Department of Pharmacology, University of Texas Health Science Center, San Antonio 78284-7764.
Buchholz
R A
RA
Haywood
J R
JR
D000818:Animals; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology; D002908:Chronic Disease; D006339:Heart Rate / Q000187:drug effects; D006977:Hypertension, Renal / Q000503:physiopathology*; D008297:Male; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology / Q000503:physiopathology*; D011188:Potassium / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012964:Sodium / Q000097:blood; D013564:Sympathetic Nervous System / Q000503:physiopathology
D001127:Arginine Vasopressin; C025043:vasopressin, 1-(1-mercaptocyclohexaneacetic acid)-2-(O- methyl-L-tyrosine)-8-L-arginine-; D002216:Captopril; D012964:Sodium; D011188:Potassium