title: Effects of subcutaneous administration of the gamma-aminobutyric acid(A) receptor agonist muscimol on water intake in water-deprived rats.
abstract: The effects of the gamma-aminobutyric acid(A) (GABA(A)) receptor agonist muscimol were investigated on water intake in rats that had been deprived of water for 16 h. Muscimol (0.5-2.0 mg/kg sc) produced a dose-related inhibition of water consumption in both male (n=8) and female (n=8) rats, with maximal suppression of drinking occurring during the first 30 min after administration. Doses of 1 and 2 mg/kg produced significant decreases in water intake (P<.01), while a lower dose of 0.5 mg/kg was without effect. The hypodipsic effect of muscimol (1.0 mg/kg sc) was abolished by pretreatment of the animals with the GABA(A) receptor antagonist bicuculline (1 mg/kg sc). Furthermore, muscimol (2 mg/kg sc) did not produce aversion in a two-bottle conditioned taste aversion test, indicating that the suppressant effects of muscimol on water intake are not due to drug-induced malaise. The results suggest that systemic administration of muscimol produces a behaviourally specific suppression of primary drinking in rats by a GABA(A) receptor-mediated mechanism. Moreover, this action of muscimol appears to be independent of the gender of the animals.
authors.affiliation: Neuropharmacology Research Group, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, Hampshire, UK.
authors.forename: Abigail J
authors.initials: AJ
authors.lastname: Houston
authors.forename: John C L
authors.initials: JC
authors.lastname: Wong
authors.forename: Ivor S
authors.initials: IS
authors.lastname: Ebenezer
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D001640:Bicuculline / Q000008:administration & dosage / Q000494:pharmacology; D004326:Drinking / Q000187:drug effects*; D005260:Female; D018755:GABA Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D018756:GABA Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D007279:Injections, Subcutaneous; D008297:Male; D009118:Muscimol / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects*; D012727:Sex Characteristics; D013649:Taste / Q000187:drug effects; D014868:Water Deprivation / Q000502:physiology*
chemical_list: D018755:GABA Agonists; D018756:GABA Antagonists; D011963:Receptors, GABA-A; D009118:Muscimol; D001640:Bicuculline