SCHEDULE INDUCED SELF INJECTION OF HEROIN: DOSE RESPONSE RELATIONSHIPS

Acquisition of heroin self administration is facilitated by reduced body weight and by a fixed time food delivery schedule. The introduction of these environmental factors did not markedly influence either the ED50 for heroin self-administration or the amount of drug intake over graded dose levels. Previous studies suggest the latter variables can serve as an index of opiate reinforcing efficacy. Thus, it might be that weight reduction and scheduled food affect the rate of acquisition of heroin intake more than they affect the reinforcing efficacy of the drug.