Increased intravenous drug self-administration during deprivation of other reinforcers

Previous research has shown that food deprivation markedly increased self-adminstration of a variety of drugs. The present study concerns an extension of the food deprivation effect to a range of doses and other forms of deprivation. In each experiment, etonitazene infusions were continously available to rats under the following sequence of satiation (S) or deprivation (D) sessions: S, S, D, S, S, D, S, S, D, S, S, S. Each infusion contingent upon a lever-press response, and session lenght was 4 hr. In the first experiment, five groups of rats, each receiving a different etonitaze dose: 0 (saline), 5, 10, 20 or 40 μg/kg, were tested under conditions of food satiation (free access) and deprivation (8 g food, sessions). Food deprivation produced no increases in responding maintained by saline, but it produced nearly parallel increases in respon3ing across all drug doses. In the second experiment, effects of water satiation (free access) and deprivation (no water) were tested at the 10 μg/kg etonitaze unit dose. Etonitazene-maintained responding was more than twice as high during water deprivation sessions as during satiation sessions. In the third experiment, rats receiving saline infusion (after brief exposure to 10 μg/kg etonitazene infusions to elevate response rates) did not show any systematic changes in saline-maintained behavior as a result of water deprivation or satiation. In the fourth experiment, rats were allowed continous access to food, water and etonitazene infusions (10 μg/kg). In addition, they were given a drinking solution containing 3% glucose and 0.125% saccharin (G + S). When the rats were deprived of the G + S solution, they showed small but reliable increases in etonitazene self-administration. The present results extend previous findings with food deprivation to a range of doses and other deprivation conditions, suggesting that drug-maintained behavior can be controlled by alterations in a variety of other reinforcing events in the environment.