Abstract
Rationale: MS-377 ((R)-(+)-1-(4-chlorophenyl)-3-[4-(2-methoxyethyl)piperazin-1-yl]methyl-2-pyrrolidinone l-tartrate) was discovered as a new chemical entity with affinity for σ receptors and without affinities for dopamine receptors. Objective: In the present study, we examined the antipsychotic profile of MS-377 in several in vitro and in vivo experiments. Methods: As in vitro assays, radioligand binding assays for σ1, σ2, D2 and 5-HT2 receptors were performed. As in vivo animal models, the effects of MS-377 on several behavioral models induced by phencyclidine (PCP), (+)-N-allylnormetazocine (NANM), apomorphine (Apo) and 5-hydroxytryptamine (5-HTP) were evaluated. All assay systems were conducted using the clinically active antipsychotic agents as reference standards. Results: MS-377 displaced ligand bound to σ1 receptors in vitro. However, no such displacement was observed at σ2 or 5-HT2 receptors in vitro, or at D2 receptors either in vitro or in vivo. In behavioral studies, MS-377 inhibited both NANM- and PCP-induced head-weaving at low doses in mice and rats, whereas antipsychotic agents used in the present study were only effective against NANM- induced head-weaving behavior in mice. In addition, MS-377 antagonized Apo-induced climbing behavior and 5-HTP-induced head-twitching behavior in mice. MS-377 was inactive in models of extrapyramidal side effect (EPS) liability such as prevention of Apo-induced stereotypy and induction of catalepsy in rats. Conclusion: The present study demonstrated that MS-377 had not only anti-PCP activity but also anti-dopaminergic and anti-serotonergic activities in vivo, without acting directly through D2 or 5-HT2 receptors. Therefore, MS-377 could be a novel antipsychotic agent with clinical efficacy for overall symptoms of schizophrenia including its negative symptoms and without EPS liability.
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Received: 5 October 1998 / Final version: 22 January 1999
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Takahashi, S., Sonehara, K., Takagi, K. et al. Pharmacological profile of MS-377, a novel antipsychotic agent with selective affinity for σ receptors. Psychopharmacology 145, 295–302 (1999). https://doi.org/10.1007/s002130051061
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DOI: https://doi.org/10.1007/s002130051061