Dipsogenic-like and behavioural effects of bombesin administered intracerebroventricularly to sheep.
Bombesin administered intracerebroventricularly both by bolus injection (3.0, 6.0, 12.5, 25.0 and 50.0 ng kg-1) and slow infusion (0.4, 0.8 and 1.6 ng kg-1 min-1 for 30 min) potently and promptly stimulated water intake in sheep. This effect was dose dependent and bombesin was slightly more potent than angiotensin II (on a molar basis); both caused behavioural alterations (scratching and licking) in treated animals. Intravenous bolus injections of bombesin at doses up to 2500 ng kg-1 did not elicit either dipsogenic-like or behavioural effects, unlike angiotensin II. The receptor antagonist of angiotensin II, saralasin, provoked drinking in sheep at doses of 18.7, 37.5 and 75.0 ng kg-1 by intracerebroventricular bolus injection. These results surprisingly revealed that bombesin, a potent inhibitor of water intake in other mammals (rats and pigs), exerted in sheep dipsogenic-like effects similar to those in pigeons and ducks.
Belloli
C
C
Institute of Veterinary Pharmacology, Toxicology and Experimental Therapeutics, University of Milan, Italy.
Beretta
C
C
Marchisio
A
A
Ormas
P
P
Tanzi
G B
GB
Volonte'
M
M
D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001839:Bombesin / Q000008:administration & dosage / Q000494:pharmacology*; D004326:Drinking / Q000187:drug effects*; D005260:Female; D007276:Injections, Intraventricular; D012504:Saralasin / Q000008:administration & dosage / Q000494:pharmacology; D012756:Sheep / Q000502:physiology*
D000804:Angiotensin II; D012504:Saralasin; D001839:Bombesin