Interplay between 5-HT2C and 5-HT1A receptors in the dorsal periaqueductal gray in the modulation of fear-induced antinociception in mice

Author(s)

Baptista-de-Souza, Daniela ^{[1, 2, 3]} ; Pelarin, Vinicius ^{[1, 3]} ; Canto-de-Souza, Lucas ^{[4, 2]} ; Nunes-de-Souza, Ricardo Luiz ^{[1, 4, 2]} ; Canto-de-Souza, Azair ^{[1, 2, 3, 5]}

Affiliation

^[1] Joint Grad Program Physiol Sci UFSCar UNESP, BR-13565905 Sao Carlos, SP - Brazil

^[2] Inst Neurosci & Behav, Av Cafe 2-450, BR-14050220 Ribeirao Preto, SP - Brazil

^[3] Fed Univ Sao Carlos UFSCar, Dept Psychol, BR-13565905 Sao Carlos, SP - Brazil

^[4] Univ Estadual Paulista UNESP, Sch Pharmaceut Sci, Lab Pharmacol, BR-14800903 Araraquara, SP - Brazil

^[5] Grad Program Psychol UFSCar, Rod Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Neuropharmacology; v. 140, p. 100-106, SEP 15 2018.
• Web of Science Citations: 1

Abstract

The confinement of rodents to the open arm of the elevated-plus maze provokes antinociception (OAA). As a type of defensive reaction, the OAA has been investigated through systemic and intramesencephalic (e.g., dorsal portion of the periaqueductal gray - dPAG) injections of anxiolytic-like drugs {[}e.g., serotonergic (5-HT) receptor agonists or antagonists]. Here we investigated the effects of (i) intra-dPAG injections of a 5HT(2C) receptor agonist (MK-212; 0.21 or 0.63 nmol) and antagonist (SB 242084; 0.01, 0.1 or 1.0 nmol); (ii) combined injections of SB 242084 and MK-212 into the dPAG; (iii) combined injections of SB 242084 with 8-OHDPAT (10 nmol) into the dPAG on the OAA in male Swiss mice. Nociception was assessed with the writhing test induced by acetic acid injection. Results showed that (i) intra-dPAG injection of MK-212 (0.63 nmol) increased the OAA; (ii) intra-dPAG SB 242084 (1.0 nmol) prevented the OAA; (iii) SB 242084 (0.1 nmol, a dose devoid of intrinsic effect on nociception) blocked the OAA enhancement provoked by MK-212 and enabled 8-OH-DPAT to prevent the OAA. These results suggest that OAA is mediated by 5-HT2C receptors within the dPAG. Intra-dPAG SB242084 administration provoked similar results on the effects produced by MK-212 and 8-OH-DPAT on OAA. In addition, the dPAG 5-HT1A and 5-HT2C receptors interact each other in the modulation of OAA. 2018 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 10/06654-4 - Antinociception induced by open arms of Elevated Plus Maze in mice: assessment of possible modulation by antidepressants fluoxetine, sertraline and imipramine
• Grantee: Vinícius Pelarin Do Nascimento Costa
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 11/19472-4 - Involvement of histaminergic system in limbic structures on the memory of inhibitory avoidance in mice
• Grantee: Lucas Canto de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/17938-6 - Role of serotonergic receptors of periaqueductal gray on antinociception of mice confined to open arms the elevated plus-maze
• Grantee: Daniela Baptista de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)