Evidence that nitric oxide modulates drinking behaviour.
The involvement of the L-arginine-nitric oxide (NO) pathway in brain, in the regulation of drinking behaviour, has been evaluated by injecting L-arginine and N omega-nitro-L-arginine methyl ester (L-NAME) into the lateral cerebral ventricle (i.c.v.). L-Arginine (5 and 10 micrograms/rat), but not D-arginine, was antidipsogenic when administered to 24 hr water-deprived rats but did not change the intake of water in normally hydrated rats. However, L-NAME (5 and 10 micrograms/rat) did antagonize the effect of L-arginine in water-deprived animals but, by itself, did not increase thirst. L-Arginine (100 ng), when injected into the preoptic area significantly reduced water deprivation-induced drinking. The same dose was unaffective when given intraventricularly. Finally, L-arginine (5 and 10 micrograms/rat, i.c.v.) inhibited drinking induced by intraventricular injection of angiotensin II (250 ng/rat). The effect was dose-dependent. The results indicate that: (1) NO acts as an inhibitory mechanism when thirst is stimulated by water deprivation or by angiotensin II; (2) the preoptic area might be one of the central sites of antidipsogenic action of NO and (3) nitric oxide synthase might be inhibited during water deprivation.
Calapai
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G
Institute of Pharmacology, School of Medicine, University of Messina, Italy.
Squadrito
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F
Altavilla
D
D
Zingarelli
B
B
Campo
G M
GM
Cilia
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M
Caputi
A P
AP
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D004327:Drinking Behavior / Q000187:drug effects*; D004357:Drug Synergism; D007267:Injections; D007276:Injections, Intraventricular; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000494:pharmacology*; D011301:Preoptic Area; D051381:Rats; D011919:Rats, Inbred Strains; D013237:Stereoisomerism; D014868:Water Deprivation
D000804:Angiotensin II; D009569:Nitric Oxide; D001120:Arginine; D019331:NG-Nitroarginine Methyl Ester