Transient reinforcing effects of phenylisopropylamine and... : Behavioural Pharmacology (original) (raw)
ORIGINAL ARTICLES
Transient reinforcing effects of phenylisopropylamine and indolealkylamine hallucinogens in rhesus monkeys
Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
Sponsorship: These studies were supported by USPHS Grants DA09161 and DA05923.
Correspondence and requests for reprints to W.E. Fantegrossi, Department of Pharmacology, University of Michigan Medical School, 1301 MSRB III, Ann Arbor, MI, 48109-0632, USA
E-mail: [email protected]
Received 9 May 2003 Accepted as revised 23 January 2004
Abstract
Relatively few studies have assessed the reinforcing effects of hallucinogenic compounds, and no such studies have attempted to engender contingent responding for these compounds in animals with behavioral histories that include experience with serotonergically mediated reinforcing effects. The objectives of the present study were to investigate the capacity of several hallucinogenic compounds to maintain self-administration behavior in rhesus monkeys with a previous history of 3,4-methylenedioxymethamphetamine (MDMA) self-administration, and to compare these effects across a range of doses of drugs from two structural classes (indolealkylamines and phenylisopropylamines). The results indicate that no compound generated reliable responding and that no subject ever self-administered 4-iodo-2,5-dimethoxyphenylisopropylamine (DOI) at rates above those engendered by contingent saline. However, 3 out of 4 subjects did respond at rates between 0.75 and 3.0 responses/s in one or more sessions where N,_N_-dimethyltryptamine (DMT), mescaline or psilocybin were available. During some of these sessions in which self-administration was maintained, animals earned a majority of all available infusions and appeared intoxicated by the end of the session. This pattern of transient self-administration may indicate that these compounds have weak reinforcing effects, or mixed reinforcing and aversive effects.
© 2004 Lippincott Williams & Wilkins, Inc.