Oral self-administration of cocaine: chronic excessive intake by schedule induction.
Rats were exposed to daily 3-hr schedule-induced polydipsia sessions (fixed-time 1 min food-pellet delivery) with a cocaine hydrochloride solution as the available session fluid. Cocaine intake level (mg/kg) was a direct function of solution concentration (0.02-0.2 mg/ml). In a second experiment with 0.15 mg/ml cocaine solution available, mean daily session cocaine intake remained constant at about 40 mg/kg over the 5-week period of the experiment. Post-session serum samples of animals drinking either 0.15 or 0.2 mg/ml cocaine solution yielded serum cocaine values that were similar to those producing subjective "highs" in coca-leaf chewers and experienced users of cocaine. The schedule-induction technique can be used to induce the intake of drug solutions, including those which perhaps taste bitter, so that chronic and pharmacologically significant consequences ensue.
Department of Psychology, Rutgers University, New Brunswick, NJ 08903.
M
M
Tang
J L
JL
Falk
D000818:Animals; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012055:Reinforcement Schedule; D012646:Self Administration
D003042:Cocaine