Unravelling cortico-hypothalamic pathways regulating unconditioned fear-induced antinociception and defensive behaviours

Autor(es)

Falconi-Sobrinho, Luiz Luciano ; dos Anjos-Garcia, Tayllon ; Elias-Filho, Daoud Hibrahim ; Coimbra, Norberto Cysne

• Tipo de documento: Artigo Científico
• Fonte: Neuropharmacology; v. 113, p. 19-pg., 2017-02-01.

Resumo

The medial prefrontal cortex can influence unconditioned fear-induced defensive mechanisms organised by diencephalic neurons that are under tonic GABAergic inhibition. The posterior hypothalamus (PH) is involved with anxiety- and panic attack-like responses. To understand this cortical mediation, our study characterised anterior cingulate cortex (ACC)-PH pathways and investigated the effect of ACC local inactivation with lidocaine. We also investigated the involvement of PH ionotropic glutamate receptors in the defensive behaviours and fear-induced antinociception by microinjecting NBQX (an AMPA/kainate receptor antagonist) and LY235959 (a NMDA receptor antagonist) into the PH. ACC pretreatment with lidocaine decreased the proaversive effect and antinociception evoked by GABA(A) receptor blockade in the PH, which suggests that there may be descending excitatory pathways from this cortical region to the PH. Microinjections of both NBQX and LY235959 into the PH also attenuated defensive and antinociceptive responses. This suggests that the blockade of AMPA/kainate and NMDA receptors reduces the activity of glutamatergic efferent pathways. Both inputs from the ACC to the PH and glutamatergic hypothalamic short links disinhibited by intra-hypothalamic GABA(A) receptors blockade are potentially implicated. Microinjection of a bidirectional neurotracer in the PH showed a Cg1-PH pathway and PH neuronal reciprocal connections with the periaqueductal grey matter. Microinjections of an antegrade neurotracer into the Cg1 showed axonal fibres and glutamatergic vesicle-immunoreactive terminal boutons surrounding both mediorostral-lateroposterior thalamic nucleus and PH neuronal perikarya. These data suggest a critical role played by ACC-PH glutamatergic pathways and AMPA/kainate and NMDA receptors in the panic attack-like reactions and antinociception organised by PH neurons. (C) 2016 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 12/03798-0 - Envolvimento de receptores opióides e endocanabinóides da substância negra na modulação da atividade da via GABAérgica nigro-tectal durante a organização do comportamento de defesa eliciado por roedores confrontados com serpentes veneníferas
• Beneficiário: Norberto Cysne Coimbra
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 07/01174-1 - Estudo do envolvimento do sistema opióide, serotoninérgico e noradrenérgico do sistema endógeno de inibição de dor em processos antinociceptivos induzidos por reações de fuga orientada evocada pela estimulação química do hipotálamo medial
• Beneficiário: Norberto Cysne Coimbra
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/10984-8 - Influência do córtex cingulado anterior e o envolvimento de receptores glutamatérgicos NMDA e AMPA/Cainato hipotalâmicos na organização do comportamento de defesa e da antinocicepção induzidos pelo medo, elaborados pelo hipotálamo posterior
• Beneficiário: Luiz Luciano Falconi Sobrinho
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 02/01497-1 - Estudo do envolvimento do núcleo magno da rafe, do núcleo gigantocelular e núcleo pré-tectal anterior, e de receptores opiódes, kappa e delta serotoninérgicos 5HT2/1C, e noradrenérgicos alfa, beta, na analgesia pós-cital: um estudo neuroanatômico e neuropsicofisiológico em um modelo experimental de epilepsia
• Beneficiário: Daoud Hibrahim Elias Filho
• Modalidade de apoio: Bolsas no Brasil - Programa Capacitação - Treinamento Técnico