Effects of the GABAB receptor agonists baclofen and 3-aminopropylphosphinic acid (3-APA) on food intake in rats.
It has previously been demonstrated that central administration of the GABAB agonist baclofen increases food intake in non-deprived or satiated animals by action at the central GABAB receptors. It has also been shown that systemic administration of baclofen increases food intake in non-deprived rats. Although baclofen crosses the blood brain barrier from systemic circulation to enter the brain, it is conceivable that it may increase food intake by a peripheral mode of action. This possibility was examined in the present study. The effects of intraperitoneal (i.p.) administration of the GABAB receptor agonists baclofen and 3-aminopropylphosphinic acid (3-APA) were investigated on food intake in non-deprived rats. 3-APA is a potent GABAB agonist that does not penetrate the blood brain barrier. The results show that while baclofen (1-4 mg/kg) increases food intake in a dose-related manner, 3-APA (0.5-2 mg/kg) has no effects on food consumption. The results indicate that a peripheral GABAB mechanism is not involved in the hyperphagia elicited by systemic administration of baclofen and suggests that the drug increases food intake by a central mode of action.
Ebenezer
I S
IS
Neuropharmacology Research Group, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, England. ivor.ebenezer@port.ac.uk
Patel
S M
SM
D000818:Animals; D001418:Baclofen / Q000008:administration & dosage / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects*; D018755:GABA Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D058786:GABA-B Receptor Agonists; D007274:Injections, Intraperitoneal; D008297:Male; D009943:Organophosphorus Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D018755:GABA Agonists; D058786:GABA-B Receptor Agonists; D009943:Organophosphorus Compounds; C061388:3-aminopropylphosphinic acid; D001418:Baclofen