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Facilitation of 5-HT(2A/2C)-mediated neurotransmission in the ventromedial hypothalamic nucleus decreases anxiety in the elevated T-maze.
Behav Brain Res. 2011 Jan 20; 216(2):692-8.BB

Abstract

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.

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Authors+Show Affiliations

da Silva ES
Department of Biosciences, Federal University of São Paulo, Santos, Brazil.
Poltronieri SC
No affiliation info available
Nascimento JO
No affiliation info available
Zangrossi H
No affiliation info available
Viana MB
No affiliation info available

MeSH

AnimalsAnxietyAvoidance LearningEscape ReactionExploratory BehaviorMaleMaze LearningMotor ActivityRatsRats, WistarReceptor, Serotonin, 5-HT2AReceptor, Serotonin, 5-HT2CSerotonin AgentsVentromedial Hypothalamic Nucleus

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20883726

Citation

da Silva, E S., et al. "Facilitation of 5-HT(2A/2C)-mediated Neurotransmission in the Ventromedial Hypothalamic Nucleus Decreases Anxiety in the Elevated T-maze." Behavioural Brain Research, vol. 216, no. 2, 2011, pp. 692-8.
da Silva ES, Poltronieri SC, Nascimento JO, et al. Facilitation of 5-HT(2A/2C)-mediated neurotransmission in the ventromedial hypothalamic nucleus decreases anxiety in the elevated T-maze. Behav Brain Res. 2011;216(2):692-8.
da Silva, E. S., Poltronieri, S. C., Nascimento, J. O., Zangrossi, H., & Viana, M. B. (2011). Facilitation of 5-HT(2A/2C)-mediated neurotransmission in the ventromedial hypothalamic nucleus decreases anxiety in the elevated T-maze. Behavioural Brain Research, 216(2), 692-8. https://doi.org/10.1016/j.bbr.2010.09.016
da Silva ES, et al. Facilitation of 5-HT(2A/2C)-mediated Neurotransmission in the Ventromedial Hypothalamic Nucleus Decreases Anxiety in the Elevated T-maze. Behav Brain Res. 2011 Jan 20;216(2):692-8. PubMed PMID: 20883726.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Facilitation of 5-HT(2A/2C)-mediated neurotransmission in the ventromedial hypothalamic nucleus decreases anxiety in the elevated T-maze. AU - da Silva,E S, AU - Poltronieri,S C, AU - Nascimento,J O G, AU - Zangrossi,H,Jr AU - Viana,M B, Y1 - 2010/09/29/ PY - 2010/08/20/received PY - 2010/09/10/revised PY - 2010/09/16/accepted PY - 2010/10/2/entrez PY - 2010/10/5/pubmed PY - 2011/3/23/medline SP - 692 EP - 8 JF - Behavioural brain research JO - Behav Brain Res VL - 216 IS - 2 N2 - 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. SN - 1872-7549 UR - https://www.unboundmedicine.com/medline/citation/20883726/Facilitation_of_5_HT_2A/2C__mediated_neurotransmission_in_the_ventromedial_hypothalamic_nucleus_decreases_anxiety_in_the_elevated_T_maze_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0166-4328(10)00639-X DB - PRIME DP - Unbound Medicine ER -