GABA/benzodiazepine receptors in the ventromedial hypothalamic nucleus regulate both anxiety and panic-related defensive responses in the elevated T-maze

GABA/benzodiazepine receptors in the ventromedial hypothalamic nucleus regulate both anxiety and panic-related defensive responses in the elevated T-maze

Author Bueno, Cintia Heloina Google Scholar
Zangrossi, Helio Google Scholar
Viana, Milena de Barros Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract It has been shown that facilitation of GABA-mediated neurotransmission in the medial nucleus of the amygdala and the dorsal periaqueductal gray (dPAG) inhibits the escape, but not the inhibitory avoidance response generated in the elevated T-maze test of anxiety (ETM). These defensive behaviors have been associated with panic and generalized anxiety, respectively. Previous evidence indicates that the dorsomedial part of the ventromedial hypothalamus (VMHdm), which is interconnected with these two brain areas, is also part of the neurobiological substrate controlling escape behavior. in the present study, we investigated in male Wistar rats whether the intra-VMHdm injection of GABA-modulating drugs differently affect the two defensive tasks measured in the ETNI. the results showed that the microinjection of the benzodiazepine (BZD) receptor agonist midazolam (10, 20 and 40 nmol), the GABA(A) receptor agonist muscimol (2, 4 and 8 nmol) or the GABA(B) receptor agonist baclofen (2, 4 and 8 nmol) impaired inhibitory avoidance and escape performance, an anxiolytic and panicolytic-like effect, respectively. On the other hand, local administration of the BZD inverse agonist FG 7142 (20, 40 and 80 pmol) facilitated both behaviors, suggesting anxiogenic and panicogenic-like effects. These results were not due to motor alterations, since the drugs did not affect exploratory behavior in an open field. the data suggest that GABA(A)/BZD and GABAB receptors within the VMHdm are involved not only in the control of panic-related, but also of anxiety-related behaviors. (c) 2007 Elsevier Inc. All fights reserved.
Keywords ventromedial hypothalamus
GABA
elevated T-maze
escape
inhibitory avoidance
panic
generalized anxiety
Language English
Date 2007-09-14
Published in Brain Research Bulletin. Oxford: Pergamon-Elsevier B.V., v. 74, n. 1-3, p. 134-141, 2007.
ISSN 0361-9230 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 134-141
Origin http://dx.doi.org/10.1016/j.brainresbull.2007.06.003
Access rights Closed access
Type Article
Web of Science ID WOS:000249231300017
URI http://repositorio.unifesp.br/handle/11600/30041

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