BMY-14802, a sigma ligand and potential antipsychotic drug, reverses amphetamine-induced changes in neostriatal single-unit activity in freely moving rats.
The effects of BMY-14802 (5, 10, or 20 mg/kg), a sigma-receptor ligand showing preclinical evidence of antipsychotic efficacy, were tested on single-unit activity in the neostriatum of freely moving rats with or without pretreatment with 1.0 mg/kg D-amphetamine. Relative to resting baseline, amphetamine activated the large majority of neurons that changed firing rate in close temporal association with movement. All doses of BMY-14802 reversed this neuronal response, but the effect was most pronounced at 20 mg/kg. This dose, however, was equally likely to reverse or to induce a haloperidol-like potentiation of those neurons inhibited by amphetamine. In contrast, 10 mg/kg BMY-14802 consistently reversed amphetamine-induced neuronal inhibitions. All doses of BMY-14802 attenuated the locomotor effects of amphetamine, but only the higher doses also blocked other aspects of the amphetamine behavioral response. By itself, BMY-14802 dose dependently inhibited motor-related neurons, but elicited less behavioral activation than amphetamine. BMY-14802 (20 mg/kg) also induced hindlimb ataxia and occasional backwards locomotion. Haloperidol (1.0 mg/kg) reliably suppressed both behavior and neuronal activity when injected 30 min after BMY-14802, whether or not amphetamine pretreatment was given. Thus, BMY-14802 shares with other neuroleptics the capacity to reverse amphetamine-induced excitations of neostriatal motor-related neurons, whereas other effects of BMY-14802 reveal some haloperidol-like actions at 20 mg/kg that do not occur at lower doses.
Department of Psychology, Indiana University, Bloomington 47405.
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Wang
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Haracz
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Rebec
D000661:Amphetamine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D003342:Corpus Striatum / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D004594:Electrophysiology; D008024:Ligands; D008297:Male; D009043:Motor Activity; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D011743:Pyrimidines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017480:Receptors, sigma / Q000378:metabolism
D014150:Antipsychotic Agents; D008024:Ligands; D011743:Pyrimidines; D017480:Receptors, sigma; C050408:alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine butanol; D000661:Amphetamine