A SINGLE INJECTION OF EITHER FLUPENTIXOL DECANOATE OR HALOPERIDOL DECANOATE PRODUCES LONG-TERM CHANGES IN COCAINE SELF-ADMINISTRATION IN RATS

The effect of decanoate forms of flupenthixol and haloperidol on cocai ne self-administration was evaluated. Forty-two male Wistar rats were implanted with chronically indwelling jugular cannulae and trained to self-administer cocaine (0.6 mg/inj) either on a fixed ratio (FR) 1 sc hedule or a progressive ratio (PR) schedule. After a stable response p attern was established, animals received a single i.m. injection of ei ther flupenthixol (2.0 mg), haloperidol (2.5 mg) or vehicle (0.1 ml oi l). Both neuroleptics produced a long lasting increase in cocaine inta ke on a FR 1 schedule which reached a peak on post-injection day three and diminished slowly over the next seven days. All animals maintaine d on a PR schedule showed a long lasting decline in breaking points. T hese data suggest that the decanoate forms of flupenthixol and haloper idol may attenuate the reinforcing effects of cocaine and indicate tha t the therapeutic value of depot neuroleptics as anti-cocaine treatmen ts would depend on the economics of cocaine availability.