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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

GABA(A) receptor blockade in dorsomedial and ventromedial nuclei of the hypothalamus evokes panic-like elaborated defensive behaviour followed by innate fear-induced antinociception

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Author(s):
Freitas, Renato Leonardo [1] ; Uribe-Marino, Andres [1] ; Castiblanco-Urbina, Maria Angelica [1] ; Elias-Filho, Daoud Hibraim [1] ; Coimbra, Norberto Cysne [2]
Total Authors: 5
Affiliation:
[1] Univ Sao Paulo, INeC, BR-14040901 Ribeirao Preto, SP - Brazil
[2] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Farmacol, Lab Neuroanat & Neuropsicobiol, BR-14049900 Ribeirao Preto, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Brain Research; v. 1305, p. 118-131, DEC 11 2009.
Web of Science Citations: 32
Abstract

Dysfunction in the hypothalamic GABAergic system has been implicated in panic syndrome in humans. Furthermore, several studies have implicated the hypothalamus in the elaboration of pain modulation. Panic-prone states are able to be experimentally induced in laboratory animals to study this phenomenon. The aim of the present work was to investigate the involvement of medial hypothalamic nuclei in the organization of panic-like behaviour and the innate fear-induced oscillations of nociceptive thresholds. The blockade of GABA(A) receptors in the neuronal substrates of the ventromedial. or dorsomedial hypothalamus was followed by elaborated defensive panic-like reactions. Moreover, innate fear-induced antinociception was consistently elicited after the escape behaviour. The escape responses organized by the dorsomedial and ventromedial hypothalamic nuclei were characteristically more elaborated, and a remarkable exploratory behaviour was recorded during GABA(A) receptor blockade in the medial hypothalamus. The motor characteristic of the elaborated defensive escape behaviour and the patterns of defensive alertness and defensive immobility induced by microinjection of the bicuculline either into the dorsomedial. or into the ventromedial hypothalamus were very similar. This was followed by the same pattern of innate fear-induced antinociceptive response that lasted approximately 40 min after the elaborated defensive escape reaction in both cases. These findings suggest that dysfunction of the GABA-mediated neuronal system in the medial hypothalamus causes panic-like responses in laboratory animals, and that the elaborated escape behaviour organized in both dorsomedial and ventromedial hypothalamic nuclei are followed by significant innate-fear-induced antinociception. Our findings indicate that the GABA(A) receptor of dorsomedial and ventromedial hypothalamic nuclei are critically involved in the modulation of panic-like behaviour. (C) 2009 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 09/01153-0 - Involvement of locus coeruleus neural pathways and noradrenergic neurotransmission in the dorsal raphe nucleus in antinociceptive processes induced by oriented escape reactions evoked by chemical stimulation of the medial hypothalamus
Grantee:Andres Uribe Marino
Support Opportunities: Scholarships in Brazil - Master