T B Nucci1, L G S Branco, L H Gargaglioni. 1. Department of Physiology, Medicine School of Ribeirao Preto, University of São Paulo, São Paulo, Brazil.
Abstract
AIM: In the present study, we assessed the role of 5-hydroxytryptamine (5-HT) receptors (5-HT(1A), 5-HT(2) and 5-HT(7)) 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 microL microinjection of WAY-100635 (5-HT(1A) receptor antagonist, 3 microg 0.1 microL(-1), 56 mm), ketanserin (5-HT(2) receptor antagonist, 2 microg 0.1 microL(-1), 36 mm) and SB269970 (5-HT(7) receptor antagonist, 4 microg 0.1 microL(-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-HT(1A) receptors in the NRM increases the hypoxic ventilatory response.
AIM: In the present study, we assessed the role of 5-hydroxytryptamine (5-HT) receptors (5-HT(1A), 5-HT(2) and 5-HT(7)) 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 microL microinjection of WAY-100635 (5-HT(1A) receptor antagonist, 3 microg 0.1 microL(-1), 56 mm), ketanserin (5-HT(2) receptor antagonist, 2 microg 0.1 microL(-1), 36 mm) and SB269970 (5-HT(7) receptor antagonist, 4 microg 0.1 microL(-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 ratsto 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-HT(1A) receptors in the NRM increases the hypoxic ventilatory response.
Authors: Olga Dergacheva; Kathleen J Griffioen; Robert A Neff; David Mendelowitz Journal: Respir Physiol Neurobiol Date: 2010-05-07 Impact factor: 1.931
Authors: Stephen Hickner; Najaah Hussain; Mariana Angoa-Perez; Dina M Francescutti; Donald M Kuhn; Jason H Mateika Journal: J Appl Physiol (1985) Date: 2013-12-12
Authors: Andrea E Corcoran; Kathryn G Commons; Yuanming Wu; Jeffrey C Smith; Michael B Harris; George B Richerson Journal: J Neurosci Date: 2014-01-01 Impact factor: 6.167
Authors: Vanessa de Souza Moreno; Kênia C Bícego; Raphael E Szawka; Janete A Anselmo-Franci; Luciane H Gargaglioni Journal: Pflugers Arch Date: 2009-10-21 Impact factor: 3.657