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BioMed Research International
Volume 2017, Article ID 8109205, 6 pages
https://doi.org/10.1155/2017/8109205
Research Article

Peripheral Antinociception Induced by Aripiprazole Is Mediated by the Opioid System

Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil

Correspondence should be addressed to Thiago Roberto Lima Romero; moc.liamg@oremoriht

Received 30 March 2017; Accepted 1 June 2017; Published 3 July 2017

Academic Editor: Gianluca Coppola

Copyright © 2017 Renata Cristina Mendes Ferreira et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Aripiprazole is an antipsychotic drug used to treat schizophrenia and related disorders. Our previous study showed that this compound also induces antinociceptive effects. The present study aimed to assess the participation of the opioid system in this effect. Methods. Male Swiss mice were submitted to paw pressure test and hyperalgesia was induced by intraplantar injection of prostaglandin E2 (PGE2, 2 μg). Aripiprazole was injected 10 min before the measurement. Naloxone, clocinnamox, naltrindole, nor-binaltorphimine, and bestatin were given 30 min before aripiprazole. Nociceptive thresholds were measured in the 3rd hour after PGE2 injection. Results. Aripiprazole (100 μg/paw) injected locally into the right hind paw induced an antinociceptive effect that was blocked by naloxone (50 μg/paw), a nonselective opioid receptor antagonist. The role of μ-, δ-, and κ-opioid receptors was investigated using the selective antagonists, clocinnamox (40 μg/paw), naltrindole (15, 30, and 60 μg/paw), and nor-binaltorphimine (200 μg/paw), respectively. The data indicated that only the δ-opioid receptor antagonist inhibited the peripheral antinociception induced by aripiprazole. Bestatin (400 μg), an aminopeptidase-N inhibitor, significantly enhanced low-dose (25 μg/paw) aripiprazole-induced peripheral antinociception. Conclusion. The results suggest the participation of the opioid system via δ-opioid receptor in the peripheral antinociceptive effect induced by aripiprazole.