Facilitation of 5-HT2A/2C-mediated neurotransmission in the ventromedial hypothalamic nucleus decreases anxiety in the elevated T-maze
| Autor: | Juliana Olivetti Guimarães Nascimento, Milena de Barros Viana, S. C. Poltronieri, E. S. da Silva, Hélio Zangrossi |
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| Rok vydání: | 2011 |
| Předmět: |
Male
Agonist medicine.medical_specialty Ketanserin medicine.drug_class Anxiety Motor Activity Open field Behavioral Neuroscience Serotonin Agents Escape Reaction Internal medicine Avoidance Learning Receptor Serotonin 5-HT2C medicine Animals Receptor Serotonin 5-HT2A Rats Wistar Maze Learning 5-HT receptor GABAA receptor T-maze Rats Endocrinology Ventromedial Hypothalamic Nucleus Hypothalamus Exploratory Behavior Serotonin Psychology medicine.drug |
| Zdroj: | Behavioural Brain Research. 216:692-698 |
| ISSN: | 0166-4328 |
| DOI: | 10.1016/j.bbr.2010.09.016 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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