Journal of Neuroscwnce Methods, 30 (1989) 141-146 141 Elsewer NSM 00999 Conditioned place preference in the corral: a procedure for measuring reinforcing properties of drugs R.U. HasentShrl, M.-S. Oitzl and J.P. Huston lnstttute of Physmloglcal Psychology. Unwersltv oJ Dusseldorj, Duvseldorf (F R G ) (Recewed 24 January 1989) (Revised 27 April 1989) (Accepted 6 June 1989) Key words: Conditioned place preference; Drug reinforcement; Morphme; Substance P; Rat A novel condltmned place preference (CPP) method is described The behavioral testing apparatus is a circular open field consisting of 4 umform quadrants that are equally preferred by the rats prior to drug treatment In an illustrative experiment, rats received an ~p mjectmn of e~ther morphine (10 mg/kg), substance P (50 ~tg/kg) or vehicle (phosphate-buffered 0 01 M aceuc acid m sahne) on 3 consecuuve clays and were placed into their assagned treatment quadrant Four ammals were simultaneously treated w~th the md of barriers, which restricted each rat to ~ts treatment quadrant On the test for CPPs. when prowded a choice between the 4 quadrants, rats treated with morphine and substance P exhibited preferences for the quadrant which had been pmred wtth the drugs dlustratlng the usefulness of th~s procedure for assessing the reinforcing properties of the two drugs Gross locomotor activ~t'~ was not influenced by e~ther treatment The advantages of ttus ~ers~on of the CPP method over the conventional shuttle-box procedures are d~scussed Introduction The conditioned place preference (CPP) para- digm is frequently used to assess reinforcmg prop- erties of drugs (Bozarth, 1987; Stewart and Eikelboom, 1987 for review) especially when the use of conventmnal operant self-admlmstration procedures is precluded by economacal or other restrictions. Using this paradigm, administration of the drug is paired with a distractive environ- ment and a subsequent increase in the ttme spent m that environment during a preference test is taken as evidence for the drug's positively rein- forcing effects. This paradigm has been success- fully used to investigate the reinforcing properties of a number of pharmacologmal agents, includmg Correspondence J.P Huston, Insutute of Physiological Psy- chology. University of Dusseldorf. Unvers~tatsstrasse 1, D-4000 Dusseldorf, F R G morphine (Blander et al., 1984, Mucha and Iver- sen, 1984), cocaine (Mackey and van der Kooy, 1985; Morency and Bemnger, 1986), amphetamme (Phillips et al., 1982; Carr et al., 1988) and sub- stance P (Holzh~iuer-Oltzl et al., 1987, 1988). The most commonly used apparatus for the study of CPP has been a rectangular shuttle-box that can be divtded into two highly distinctive compartments (e.g. black vs white) by a wall or a start compartment. Since the condmoned or dis- cnmlnative stimuli that are employed often pro- duce a strong initial bias for one compartment, the less-preferred side is asstgned for drug condition- ing to avoid ceiling effects (Katz and Gormezano, 1979; Bozarth and W~se, 1981: Spyrakt and Flblger, 1988). This introduces a problem because a drug-induced shift of preference may be difficult to interpret in terms of remforcmg properties of the drug as long as some other associative or non-associative component of drug-reduced ef- fects can account for a change m preference. For 0165-0270/89/$03 50 ~ 1989 Elsevier Science Publishers B V (Blomedmal Division)