PT  - JOURNAL ARTICLE
AU  - D E McMillan
AU  - J D Leander
AU  - K H Dudley
TI  - Effects of drugs on behavior in pigeons tolerant to delta 9-tetrahydrocannabinol.
DP  - 1980 Jan 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 85--90
VI  - 212
IP  - 1
4099  - http://jpet.aspetjournals.org/content/212/1/85.short
4100  - http://jpet.aspetjournals.org/content/212/1/85.full
SO  - J Pharmacol Exp Ther1980 Jan 01; 212
AB  - Schedule-controlled behavior was used to study how drug effects on behavior are modified by the development of tolerance to delta 9-tetrahydrocannabinol (delta 9-THC). Dose-effect curves were determined for pentobarbital, d-amphetamine and morphine on responding maintained by a multiple fixed-ratio fixed-interval schedule of food presentation in pigeons. The dose-effect curves were redetermined in combination with single injections of 1.0 mg/kg dose of delta 9-THC (which itself did not affect rates of responding) in birds made tolerant to delta 9-THC by multiple injections, and in combination with the 1.0 mg/kg delta 9-THC in birds tolerant to delta 9-THC. Acute doses of 1.0 mg/kg delta 9-THC potentiated the rate-decreasing effects of all three drugs. Pigeons tolerant to delta 9-THC were cross-tolerant to pentobarbital but not to d-amphetamine and morphine. Tolerance to delta 9-THC attenuated the potentiation of the effects of all three drugs by delta 9-THC. Determination of plasma pentobarbital levels in pigeons tolerant to delta 9-THC suggested that a drug dispositional mechanism played a role in the cross-tolerance from delta 9-THC to pentobarbital.