Serotonin in the dorsal periaqueductal gray inhibits panic-like defensive behaviors in rats exposed to acute hypoxia
| Autor: | G.F. Da Silva, Mogens L. Glass, Norberto Garcia-Cairasco, T. de Oliveira Sergio, Ailton Spiacci, Hélio Zangrossi, Luiz Carlos Schenberg |
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| Rok vydání: | 2015 |
| Předmět: |
Male
Agonist Serotonin medicine.medical_specialty Microinjections medicine.drug_class Poison control RESPIRAÇÃO Periaqueductal gray chemistry.chemical_compound Serotonin Agents Internal medicine medicine Animals Periaqueductal Gray Rats Wistar GABA Modulators Hypoxia Defense Mechanisms Analysis of Variance Fluoxetine Alprazolam Dose-Response Relationship Drug 8-OH-DPAT General Neuroscience Panic disorder Panic medicine.disease Rats Endocrinology chemistry Anesthesia medicine.symptom Psychology medicine.drug |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| ISSN: | 0306-4522 |
| Popis: | It has been proposed that spontaneous panic attacks are the outcome of the misfiring of an evolved suffocation alarm system. Evidence gathered in the last years is suggestive that the dorsal periaqueductal gray (dPAG) in the midbrain harbors a hypoxia-sensitive suffocation alarm system. We here investigated whether facilitation of 5-HT-mediated neurotransmission within the dPAG changes panic-like defensive reactions expressed by male Wistar rats submitted to a hypoxia challenge (7% O2), as observed in other animal models of panic. Intra-dPAG injection of 5-HT (20 nmol), (±)-8-hydroxy-2-(di-n-propylamino) tetralin hydrobromide (8-OH-DPAT) (8 nmol), a 5-HT1A receptor agonist, or (±)-2,5-dimethoxy-4-iodo amphetamine hydrochloride (DOI) (16 nmol), a preferential 5-HT2A agonist, reduced the number of upward jumps directed to the border of the experimental chamber during hypoxia, interpreted as escape attempts, without affecting the rats' locomotion. These effects were similar to those caused by chronic, but not acute, intraperitoneal administration of the antidepressant fluoxetine (5-15 mg/kg), or acute systemic administration of the benzodiazepine receptor agonist alprazolam (1-4 mg/kg), both drugs clinically used in the treatment of panic disorder. Our findings strengthen the view that the dPAG is a key encephalic area involved in the defensive behaviors triggered by activation of the suffocation alarm system. They also support the use of hypoxia-evoked escape as a model of respiratory-type panic attacks. |
| Databáze: | OpenAIRE |
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