Inhibition of substance P-induced defensive behavior via neurokinin-1 receptor antagonism in the central and medial but not basolateral nuclei of the amygdala in male Wistar rats

Autor(es)

Bassi, G. S. ; Carvalho, M. C. ; Almada, R. C. ; Brandao, M. L.

• Tipo de documento: Artigo Científico
• Fonte: PROGRESS IN NEURO-PSYCHOPHARMACOLOGY & BIOLOGICAL PSYCHIATRY; v. 77, p. 146-154, JUL 3 2017.
• Citações Web of Science: 6

Resumo

Rationale: The production of unconditioned defensive behaviors has been related to the amygdala, a key component of the encephalic aversion system. Microinjection of the neuropeptide substance P (SP) in the amygdala elicits defensive behaviors via the activation of type 1 neurokinin (NK-1) receptors. However, no studies have investigated whether infra-amygdala SP/NK-1 mechanisms can elicit other types of defensive responses, such as antinociception and ultrasonic vocalizations (USVs). Methods: The present study investigated the effects of SP-induced activation of the neurokininergic system in three main nuclei of the amygdala-basolateral (BLA), central (CeA), and medial (MeA) nuclei-in rats that were subjected to the elevated plus maze (EPM), tail-flick test, and USV recording. The effects of SP in these amygdaloid nuclei were challenged with combined injections of the NK-1 receptor antagonist spantide. Results: The present study showed that SP injections in the CeA and MeA but not BLA exerted anxiogenic-like effects. In contrast to the CeA, the anxiogenic-like effects of SP in the MeA were not dependent on NK-1 mechanisms. In the tail-flick test, SP microinjections produced antinociceptive effects only in the MeA through NK-1 receptor activation. No USV emissions were detected after the SP microinjections. Conclusions: The present study showed that NK-1 receptors in the CeA and MeA but not BLA are involved in defensive reactions to conditions of fear. The present results may provide a better understanding of the neurochemical mediation of fear states. (AU)

• Processo FAPESP: 12/22681-7 - Envolvimento de Receptores Opioides e Endocanabinoides da Substância Negra, Parte Reticulada, na Modulação da Atividade da Via GABAérgica Nigro-tectal durante a Organização do Comportamento Defensivo de Camundongos Confrontados com Serpentes Veneníferas
• Beneficiário: Rafael Carvalho Almada
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado