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 GABA(B) agonist baclofen increases food intake in non-deprived or satiated animals by action at the central GABA(B) receptors. It has also been shown that systemic admnistration 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 studio The effects of intraperitoneal (i.p.) achninistration of the GABA, receptor agonists baclofen and 3-aminopropylphosphinic acid (3-APA) tvere investigated on food intake in non-deprived rats. 3-APA is a patent GABA(B) 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 GABA(B) mechanism is not involved in the hyperphagia elicited by systemic achninistration of baclofen and suggests that the drug increases food intake by a central mode of action. (C) 2004 Prous Science. All rights reserved.