Selective agonists at NK3 tachykinin receptors inhibit alcohol intake in Sardinian alcohol-preferring rats.

The present study evaluated the effect of tachykinin agonists, selective for different neurokinin (NK) receptors, on alcohol intake in genetically selected, Sardinian alcohol-preferring rats. Tachykinins were given by intracerebroventricular injection just before access to fluids. In rats offered both water and 8% ethanol 2 h/day, the NK3 selective agonists [Asp5.6,MePhe8]substance P(5-11), Suc[Asp6,MePhe8]substance P(6-11), and [MePhe7]neurokinin B markedly suppressed alcohol intake. The NK1 selective agonist [Sar9,Met(O2)11]substance P and the NK2 selective agonist GR 64349 did not At doses that inhibited alcohol intake, the NK3 agonists did not modify water intake; total fluid intake was significantly reduced only following 500 ng/rat of [Asp5.6,MePhe8]substance P(5-11). When rats were given a longer access to fluids (8% alcohol for 2 h, but water for 4 h), again, NK3 agonists suppressed alcohol intake, but not total fluid intake. Moreover, NK3 agonists did not modify solid food intake in food-deprived rats, nor water intake in water-deprived rats, when alcohol was not available. These findings indicate that NK3 agonists inhibit alcohol intake in Sardinian alcohol-preferring rats and that their effect is behaviorally selective. They also suggest that central NK3 receptors may be involved in alcohol intake control in rats.