STIMULATION OF TACHYKININ NK-3 RECEPTORS IN THE NUCLEUS BASALIS MAGNOCELLULARIS REDUCES ALCOHOL INTAKE IN RATS

Abstract Ciccocioppo, R., I. Panocka, C. Polidori, G. De Caro, D. Regoli and M. Massi. Stimulation of tachykinin NK-3 receptors in the nucleus basalis magnocellularis reduces alcohol intake in rats. Peptides 18(9) 1349–1355, 1997.—Injections in the nucleus basalis magnocellularis (NBM) of the tachykinin (TK) NK-3 receptor agonist [Asp 5,6 ,MePhe 8 ]substance P(5–11), also referred to as amino-senktide (NH 2 -SENK), markedly reduced alcohol intake in genetically selected alcohol-preferring rats, offered 10% ethanol 2 h/day. The threshold dose in the NBM was 0.5 ng/site, while neither 1 nor 10 ng/rat of NH 2 -SENK inhibited alcohol intake following administration into the lateral ventricle. Injection of NH 2 -SENK, 25 ng/site, in the NBM did not modify water or food intake in water deprived rats, providing evidence for the behavioral selectivity of the effect on ethanol intake. The selective TK NK-3 receptor antagonist, R-820, injected in the NBM at the dose of 1000 ng/site 5 min before NH 2 -SENK 5 ng/site, significantly reduced the effect of NH 2 -SENK. The selective TK NK-1 receptor agonist [Sar 9 ,Met(O 2 ) 11 ]substance P inhibited alcohol intake following injection in the NBM only at 25 ng/site; but the same dose induced marked grooming and inhibited also water intake in water deprived rats. The present results confirm that TK NK-3, but not NK-1, receptor agonists selectively inhibit ethanol intake in alcohol-preferring rats and suggest that the NBM is a site of action for their effect.