Effect of inhibition of nitric oxide synthesis on vasopressin secretion in conscious rabbits.
NO synthase is present in magnocellular neurons of supraoptic and paraventricular nuclei as well as in the posterior pituitary gland and may participate in control of vasopressin secretion. To test this possibility, experiments were performed in conscious, chronically prepared rabbits to determine the effect of NO synthesis inhibition with NG-nitro-L-arginine methyl ester hydrochloride (L-NAME) on basal vasopressin secretion and vasopressin responses to increased plasma osmolality (hypertonic saline infusion; P osm) and decreased blood pressure (nitroprusside infusion). L-NAME infusion (0.5 mg.kg-1 x min-1 i.v.) increased mean arterial pressure [MAP; 82.6 +/- 3.4 to 93.0 +/- 3.0 mmHg (P < 0.02)], decreased heart rate [HR; 242 +/- 12 to 209 +/- 9 beats/min (P < 0.02)], decreased plasma renin activity [PRA; 3.1 +/- 0.6 to 2.0 +/- 0.6 ng.ml-.2 h-1 (P < 0.001)], and increased plasma vasopressin concentration [P AVP; 2.2 +/- 0.3 to 4.5 +/- 1.0 pg/ml (P < 0.05)]. P(osm) did not change. Hypertonic saline infusion did not change MAP or HR but decreased PRA [4.3 +/- 0.8 to 0.9 +/- 0.2 ng.ml-1 x 2 h-1 (P < 0.01)], increased P(osm) [284 +/- 1 to 305 +/- 2 mosmol/kg H2O (P < 0.001)], and increased PAVP [2.8 +/- 0.3 to 12.7 +/- 2.7 pg/ml (P < 0.01)].(ABSTRACT TRUNCATED AT 250 WORDS)
Goyer
M
M
Department of Physiology, University of California, San Francisco 94143-0444.
Bui
H
H
Chou
L
L
Evans
J
J
Keil
L C
LC
Reid
I A
IA
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors*; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D001127:Arginine Vasopressin / Q000097:blood / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D007262:Infusions, Intravenous; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase; D009599:Nitroprusside / Q000008:administration & dosage / Q000494:pharmacology*; D011817:Rabbits; D012016:Reference Values; D012083:Renin / Q000097:blood; D013997:Time Factors
D001127:Arginine Vasopressin; D009599:Nitroprusside; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D012083:Renin; D019331:NG-Nitroarginine Methyl Ester