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.
Tang
M
M
Department of Psychology, Rutgers University, New Brunswick, NJ 08903.
Falk
J L
JL
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