Establishment of chronic intravenous drug self-administration in the C57BL/6J mouse.

A wide variety of drugs that have significant human abuse potential have been demonstrated to function as positive reinforcers in animals. The present study was designed to characterize a new mouse model of chronic intravenous drug self-administration. Adult male C57BL/6J mice, implanted with external jugular infusion catheters, were given access to response-contingent injections. They did not initiate responding for saline delivery, whereas the C57BL/6J mice initiated morphine, cocaine, methamphetamine and pentobarbital self-administration. Drug-maintained responding was consistently and significantly higher for each compound than for saline responding. In contrast to C57BL/6J mice, DBA/2J mice failed to initiate cocaine self-administration. Thus, chronic intravenous drug self-administration procedures can be adapted to the inbred mouse.