Distinct effect of 5-HT1A and 5-HT2A receptors in the medial nucleus of the amygdala on tonic immobility behavior

Autor(es)

de Paula, Bruna Balbino ^[1] ; Andrade Leite-Panissi, Christie Ramos ^{[2, 1]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Psychobiol Grad Program, Ribeirao Preto Dent Sch, Dept Morphol Physiol & Basic Pathol, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Dept Morphol Physiol & Basic Pathol, Dent Sch Ribeirao Preto, BR-14040904 Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Brain Research; v. 1643, p. 152-158, JUL 15 2016.
• Citações Web of Science: 5

Resumo

The tonic immobility (TI) response is an innate fear behavior associated with intensely dangerous situations, exhibited by many species of invertebrate and vertebrate animals. In humans, it is possible that TI predicts the severity of posttraumatic stress disorder symptoms. This behavioral response is initiated and sustained by the stimulation of various groups of neurons distributed in the telencephalon, diencephalon and brainstem. Previous research has found the highest Fos-IR in the posteroventral part of the medial nucleus of the amygdala (MEA) during TI behavior; however, the neurotransmission of this amygdaloid region involved in the modulation of this innate fear behavior still needs to be clarified. Considering that a major drug class used for the treatment of psychopathology is based on serotonin (5HT) neurotransmission, we investigated the effects of serotonergic receptor activation in the MEA on the duration of TI. The results indicate that the activation of the 5HT(1A) receptors or the blocking of the 5HT(2) receptors of the MEA can promote a reduction in fear and/or anxiety, consequently decreasing TI duration in guinea pigs. In contrast, blocking the 5HT(1A) receptors or activating the 5HT(2) receptors in this amygdalar region increased the TI duration, suggesting an increase in fear and/or anxiety. These alterations do not appear to be due to a modification of spontaneous motor activity, which might non-specifically affect TI duration. Thus, these results suggest a distinct role of the 5HT receptors in the MEA in innate fear modulation. (c) 2016 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/15084-5 - Circuitos amigdaloides na modulação do medo inato
• Beneficiário: Luiz Guilherme de Siqueira Branco
• Modalidade de apoio: Auxílio à Pesquisa - Regular