Central inhibition of nitric oxide synthase attenuates water intake but does not alter enhanced glucose utilization in the hypothalamo-neurohypophysial system of dehydrated rats.
I.c.v. administration of a nitric oxide (NO) synthase inhibitor (NG-monomethyl-L-arginine, NMMA, 500 micrograms/5 microliters) to conscious rats deprived of water for 24 h attenuated drinking and decreased glucose utilization in the subfornical organ and median preoptic nucleus. NMMA did not alter the enhanced glucose utilization in the hypothalamo-neurohypophysial system (HNS) of dehydrated rats, although it has been shown to increase, selectively, oxytocin (OT) secretion [18]. This suggests that NO may act in the neural lobe to inhibit OT secretion and promote the preferential release of vasopressin during dehydration. This effect is similar to the blockade of endogenous opiate receptors by naloxone.
Kadekaro
M
M
Division of Neurosurgery, University of Texas Medical Branch at Galveston 77555-0517.
Terrell
M L
ML
Harmann
P
P
Summy-Long
J Y
JY
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D003681:Dehydration / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism; D004326:Drinking / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism*; D007276:Injections, Intraventricular; D008297:Male; D019001:Nitric Oxide Synthase; D010121:Oxytocin / Q000097:blood; D011301:Preoptic Area / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013356:Subfornical Organ / Q000187:drug effects / Q000201:enzymology; D014667:Vasopressins / Q000097:blood; D019323:omega-N-Methylarginine
D014667:Vasopressins; D019323:omega-N-Methylarginine; D010121:Oxytocin; D001120:Arginine; D003847:Deoxyglucose; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D005947:Glucose