Vasopressin metabolite neuropeptide facilitates simultaneous temporal processing.

Rats were trained on a peak-interval timing procedure in which auditory, tactile, and visual stimuli signaled 3 different fixed-interval schedules (15, 30, and 60 s) that were presented simultaneously in a hierarchical fashion. Administration of vasopressin metabolite neuropeptide [pGlu-Asn-Cys(Cys)-Pro-Arg-Gly-NH2, 0.3 microgram/kg i.p.] had two main effects on performance. With repeated exposure the temporal criterion for each of the intervals shifted leftward on the time scale in a proportional manner, and the probability of attention to each of the intervals increased proportionally. The conclusion is that vasopressin metabolite neuropeptide facilitates simultaneous temporal processing by increasing the speed of mental processes involved in memory storage and divided attention. These results indicate that a major metabolite of arginine vasopressin that is devoid of endocrine and pressor activity can produce facilitation of cognitive processes in animals.