Neurokinin A is a specific and precocious inhibitor of water intake in neonatal rats.

Neurokinin A (NKA), which selectively inhibits only cellular dehydration (CD)-induced drinking in adult rats, exerts a more general antidipsogenic effect in pups in which it also inhibits drinking induced by angiotensin II (AII) or suckling deprivation (SD). The inhibition of drinking is precocious (1st-3rd day) and never involves the intake of milk. The inhibition of CD-induced drinking increases with age, while that of AII- or SD-induced drinking progressively decreases and disappears on day 12-15. In the rat, NKA is therefore a precocious and selective inhibitor of drinking behavior and its selectivity is achieved ontogenetically.