Dopamine receptor sensitive effect of dizocilpine on feeding behaviour.
The effect of intracerebroventricular administration of dizocilpine on feeding behaviour and adrenal corticrotropic hormone (ACTH)-induced anorexia in elevated plus maze was examined. Dizocilpine (10, 20 and 40 nmol/rat, i.c.v.) showed a dose-dependent increase in food intake in 16 h food deprived rats. Dopamine receptor antagonists such as SCH 23390 (0.25 and 0.5 mg/kg, i.p.), pimozide (0.5 and 1 mg/kg, i.p.) and haloperidol (0.25 and 0.5 mg/kg, i.p.) dose-dependently blocked dizocilpine (40 nmol)-induced potentiation of food intake. Brain dopamine depletion by pretreatment with reserpine (5 mg/kg, i.p.) and alpha-methyl-p-tyrosine (200 mg/kg, i.p.) decreased food intake in rats. Similarly, pretreatment with reserpine and alpha-methyl-p-tyrosine (AMPT) reversed the hyperphagic effect of dizocilpine (20 and 40 nmol). Intracerebroventricular administration of ACTH (5 microgram/rat) produced significant diminution of feeding duration and increased tasting latency and feeding latency in elevated plus maze which was reversed by dizocilpine (40 nmol). SCH 23390 (0.25 mg/kg), pimozide (0.5 mg/kg) and haloperidol (0.25 mg/kg) reversed the effect of dizocilpine on ACTH-induced behaviours in elevated plus maze. The present observations support and extend the hypothesis that endogenous excitatory aminoacids (EAAs) play a role in the control of food intake. Further, dizocilpine-induced hyperphagia and dizocilpine-induced reversal of ACTH effect on feeding behaviour in elevated plus maze involve DAergic mediation.
Ninan
I
I
Pharmacology Division, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh 160014, India.
Kulkarni
S K
SK
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects*; D006963:Hyperphagia / Q000139:chemically induced; D007276:Injections, Intraventricular; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
D018492:Dopamine Antagonists; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate; D000324:Adrenocorticotropic Hormone