Effects of desalivation on schedule-induced polydipsia in the rat

The development and magnitude of schedule-induced polydipisa (SIP) were examined in desalivate and control rats in two experiments. In Experiment 1 animals were placed on a noncontingent fixed time (FT) 60-sec schedule for 24 days. Results indicate speeded development but asymptotically lower levels of SIP in desalivate rats compared to controls. Home cage consumption, however, was elevated in desalivate rats. In Experiment 2 schedule length, pellet size, and the percentage of body weight were manipulated. Desalivate rats consumed less fluid during each schedule condition relative to controls, but the pattern of results across schedules was similar to controls. It was concluded that (a) desalivation attenuates SIP; (b) SIP is a learned phenomenon; (c) dry mouth theories of SIP appear inadequate; and (d) the developmental aspect of the SIP phenomenon deserves additional research attention.