Potentiation by low doses of selected neuroleptics of food-induced conditioned place preference in rats

Abstract

Numerous data support the hypothesis that dopamine (DA) plays a crucial role in reward-related processes and in incentive learning in animals and man. The possibility that various neuroleptics exhibiting a high affinity for the dopaminergic D2 (and D3) receptors could reinforce DA transmission was studied using the conditioned place preference paradigm (CPP) in rats. This was done by examining the ability of these compounds to potentiate the reinforcing properties of food in hungry rats subjected to a version of the CPP paradigm which consisted of repeated pairings of food with a single environmental cue, the floor texture of an open field. During the test session when food was no longer available in the open field, the increase in the time spent by drug-free rats on the food-paired texture was assumed to indicate the perceived rewarding value of the food. This time was significantly lengthened when the specific D2 (D3)-receptor antagonists sulpiride (4 mg/kg), amisulpride (0.5, 1 mg/kg) or pimozide (0.03, 0.06 mg/kg) were administered before the food conditioning sessions. Larger doses of these compounds as well as haloperidol, metoclopramide and the non-specific D1-D2 antagonist, chlorpromazine, regardless of the doses tested, did not exhibit this effect, but rather reduced the food-induced CPP, an action usually associated with neuroleptics. The positive effects of amisulpride was reversed by a D1 receptor antagonist, SCH 23390 (0.01 mg/kg). These results suggest that, as with amphetamine (0.5 mg/kg), some D2-specific neuroleptics enhance the incentive value of food in a narrow range of low doses, an effect proposed to reflect a "prohedonic" property.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a Dopamine D3 Receptor Ligand, BP 897, on Acquisition and Expression of Food-, Morphine-, and Cocaine-induced Conditioned Place Preference, and Food-seeking Behavior in Rats

“…This indicates that there was no unconditioned preference for either floor texture, as shown in previous studies (Guyon et al, 1993;Chaperon and Thiébot, 1996).…”

“…The experiments were conducted in a onecompartment apparatus, using an unbiased experimental design, as previously described (Guyon et al, 1993;Chaperon and Thiébot, 1996). The rats were trained and tested in four black, wooden open fields (76 Â 76 Â 50 cm 3 ) located in a dimly lit room supplied with a continuous masking noise.…”

Effects of Atypical Antipsychotic Drugs on Intralipid Intake and Cocaine-Induced Hyperactivity in Rats

“…Low doses of neuroleptics may enhance acquisition of a food rewarded place preference (Guyon et al, 1993). Olanzapine delays the slowing of running speed that occurs in rats performing a simple food-rewarded runway task as they become sated (Thornton-Jones et al, 2002).…”

Amisulpride versus Amineptine and Placebo for the Treatment of Dysthymia

“…Neuropsychobiology 1999;39: [25][26][27][28][29][30][31][32] Boyer/Lecrubier/Stalla-Bourdillon/Fleurot At low doses, it preferentially blocks presynaptic dopamine autoreceptors increasing dopamine levels and thus exerting a prohedonic activity in animals, whereas at higher doses it also blocks postsynaptic dopamine receptors leading to a decrease in dopamine transmission [6,7]. The prohedonic activity could explain the beneficial effect of amisulpride observed in certain features of schizophrenic and depressive patients.…”