5-HT1A, but not 5-HT2 and 5-HT7, receptors in the nucleus raphe magnus modulate hypoxia-induced hyperpnoea
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Data
2008-08-01
Autores
Nucci, T. B.
Branco, L. G. S.
Gargaglioni, L. H. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Blackwell Publishing
Resumo
Aim: In the present study, we assessed the role of 5-hydroxytryptamine (5-HT) receptors (5-HT1A, 5-HT2 and 5-HT7) in the nucleus raphe magnus (NRM) on the ventilatory and thermoregulatory responses to hypoxia.Methods: To this end, pulmonary ventilation (V-E) and body temperature (T-b) of male Wistar rats were measured in conscious rats, before and after a 0.1 mu L microinjection of WAY-100635 (5-HT1A receptor antagonist, 3 mu g 0.1 mu L-1, 56 mM), ketanserin (5-HT2 receptor antagonist, 2 mu g 0.1 mu L-1, 36 mM) and SB269970 (5-HT7 receptor antagonist, 4 mu g 0.1 mu L-1, 103 mM) into the NRM, followed by 60 min of severe hypoxia exposure (7% O-2).Results: Intra-NMR microinjection of vehicle (control rats) or 5-HT antagonists did not affect V-E or T-b during normoxic conditions. Exposure of rats to 7% O-2 evoked a typical hypoxia-induced anapyrexia after vehicle microinjections, which was not affected by microinjection of WAY-100635, SB269970 or ketanserin. The hypoxia-induced hyperpnoea was not affected by SB269970 and ketanserin intra-NMR. However, the treatment with WAY-100635 intra-NRM attenuated the hypoxia-induced hyperpnoea.Conclusion: These data suggest that 5-HT acting on 5-HT1A receptors in the NRM increases the hypoxic ventilatory response.
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Palavras-chave
Hypoxia, hypoxic ventilatory response, Raphe, Serotonin, Temperature, Ventilation
Como citar
Acta Physiologica. Oxford: Blackwell Publishing, v. 193, n. 4, p. 403-414, 2008.