Corticosterone does not change open elevated plus maze-induced antinociception in mice

Author(s)

Mendes-Gomes, Joyce ^{[1, 2]} ; Miguel, Tarciso Tadeu ^{[2, 3]} ; Santana Amaral, Vanessa Cristiane ^{[2, 3, 4]} ; Nunes-de-Souza, Ricardo Luiz ^{[1, 2, 3]}

Affiliation

^[1] FFCLRP USP Av, Programa Posgrad Psicobiol, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Fac Ciencias Farmaceut UNESP Rod, Lab Neuropsicofarmacol, BR-14801902 Araraquara, SP - Brazil

^[3] UFSCAR UNESP Rod, Programa Interinst Posgrad Ciencias Fisiol, BR-13565 Sao Carlos, SP - Brazil

^[4] Unidade Univ Ciencias Exatas & Tecnol, BR-75132903 Anapolis, GO - Brazil

• Document type: Journal article
• Source: Hormones and Behavior; v. 60, n. 4, p. 408-413, SEP 2011.
• Web of Science Citations: 8

Abstract

It has been demonstrated that the exposure of rodents to the standard elevated plus-maze (sEPM: 2 open and 2 enclosed arms) elicits defensive behavioral reactions and antinociception and also activates the hypothalamo-pituitary-adrenal (HPA) axis. We have recently reported that EPM-induced antinociception is particularly observed when rats and mice are exposed to a totally open EPM (oEPM: 4 open arms). Given that the oEPM seems to be a more aversive situation than the sEPM, we hypothesized that oEPM exposure would induce higher plasma levels of corticosterone than sEPM exposure in mice. In this study, we investigated the influence of exposure to eEPM (enclosed EPM: 4 enclosed arms), sEPM or oEPM on plasma corticosterone levels in mice, with or without prior nociceptive stimulation (2.5% formalin injection into the right hind paw). We also tested whether the nociceptive response in the formalin test and oEPM-induced antinociception are altered by adrenalectomy. Results showed that oEPM-exposed mice spent less time licking the injected paw than sEPM- and eEPM-exposed animals. All three types of EPM exposure increased plasma corticosterone when compared to the basal group, but sEPM- and oEPM-exposed mice showed higher corticosterone levels than eEPM-exposed mice. Prior nociceptive stimulation (formalin injection) did not enhance the plasma corticosterone response induced by the three types of EPM exposure. Indeed, formalin injection appeared to provoke a ceiling effect on plasma corticosterone concentration. Furthermore, neither the nociceptive response in the formalin test nor oEPM-induced antinociception was changed by adrenalectomy. Present results suggest that oEPM antinociception does not depend on corticosterone release in mice. (C) 2011 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 05/05171-1 - Role of mechanisms mediated by corticotropin-releasing factor and by N-methyl-D-aspartate receptor-nitric oxide complex in the reactions associated to aversive stimulus
• Grantee: Tarciso Tadeu Miguel
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 05/01988-3 - Role of dorsal and ventrolateral portions of the periaqueductal gray in the modulation of defensive behaviors and antinociception induced by aversive situations in mice
• Grantee: Joyce Mendes Gomes Tessari
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)