Unravelling cortico-hypothalamic pathways regulating unconditioned fear-induced antinociception and defensive behaviours
| Autor: | Tayllon dos Anjos-Garcia, Luiz Luciano Falconi-Sobrinho, Norberto Cysne Coimbra, D.H. Elias-Filho |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Male Hypothalamus Posterior Microinjections Pain Kainate receptor AMPA receptor Bicuculline Gyrus Cinguli 03 medical and health sciences Cellular and Molecular Neuroscience Glutamatergic chemistry.chemical_compound 0302 clinical medicine Quinoxalines Neural Pathways medicine Animals DOR Rats Wistar Pain Measurement Pharmacology Chemistry GABAA receptor Fear Rats 030104 developmental biology nervous system NMDA receptor NBQX Neuroscience Excitatory Amino Acid Antagonists 030217 neurology & neurosurgery medicine.drug Ionotropic effect |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| ISSN: | 1873-7064 |
| Popis: | 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 GABAA 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 GABAA 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. |
| Databáze: | OpenAIRE |
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