Facilitation of 5-HT2A/2C-mediated neurotransmission in the ventromedial hypothalamic nucleus decreases anxiety in the elevated T-maze

Autor(es)

da Silva, E. S. ^[1] ; Poltronieri, S. C. ^[2] ; Nascimento, J. O. G. ^[3] ; Zangrossi, Jr., H. ^[4] ; Vianaa, M. B. ^[1]

Afiliação do(s) autor(es)

^[1] Fed Univ Sao Paulo UNIFESP, Dept Biosci, Santos - Brazil

^[2] Ctr Univ Votuporanga UNIFEV, Votuporanga - Brazil

^[3] Fed Univ Sao Paulo UNIFESP, Dept Psychiat, Sao Paulo - Brazil

^[4] Univ Sao Paulo, Dept Pharmacol, BR-14049 Ribeirao Preto - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Behavioural Brain Research; v. 216, n. 2, p. 692-698, JAN 20 2011.
• Citações Web of Science: 11

Resumo

Previous evidence has shown that facilitation of GABA/benzodiazepine-mediated neurotransmission in the ventromedial hypothalamus (VMH) inhibits both escape and inhibitory avoidance responses generated in the elevated T-maze test of anxiety (ETM). These defensive behaviors have been associated with panic and generalized anxiety, respectively. Aside from GABA/benzodiazepine receptors, the VMH also contains a significant number of serotonin (5-HT) receptors, including 1A, 2A and 2C subtypes. The purpose of the present study was to investigate the effect of the activation of 5-HT(1A) and 5-HT(2A/2C) receptors in the VMH on defensive behavioral responses in rats submitted to the ETM. For that, male Wistar rats were treated intra-VMH with the 5-HT(1A) agonist 8-OH-DPAT, with the 5-HT(2A/2C) agonist DOI, with the 5-HT(2C) selective agonist MK-212, or with the 5-HT(2A/2C) antagonist ketanserin and 10 min after were submitted to the ETM. Results showed that both DOI and MK-212 significantly decreased avoidance measurements, an anxiolytic-like effect, without altering escape. 8-OH-DPAT and ketanserin were without effect, although the last drug attenuated the effects of DOI. None of the drugs altered locomotor activity in an open field. These results suggest that 5-HT(2A/2C) receptors of the VMH are involved in the regulation of inhibitory avoidance and might be of relevance to the physiopathology of generalized anxiety. (C) 2010 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 08/58815-1 - Efeito da administracao cronica de corticosterona sobre medidas de ansiedade e memoria e sobre a neurogenese hipocampal
• Beneficiário: Milena de Barros Viana
• Modalidade de apoio: Auxílio à Pesquisa - Regular