Contribution of endothelin-1 to the enhanced carotid body chemosensory responses induced by chronic intermittent hypoxia

Rey, S; Del Rio R.; Iturriaga R.

Abstract

Chronic intermittent hypoxia (CIH) enhances carotid body (CB) chemosensory responses to acute hypoxia. We tested the hypothesis that endothelin-1 (ET-1), an excitatory modulator of CB chemoreception may contribute to the enhanced CB chemosensory responses in cats exposed to cyclic hypoxic episodes repeated during 8 h for 4 days. Accordingly, we measured the ET-1 immunoreactivity (ET-ir) in the CB and plasma. Using a perfused CB preparation, we studied the effects of exogenous ET-1 and bosentan, a non-selective endothelin receptor type A and B antagonist, on the frequency of chemosensory discharges (f{hook} x) during normoxia, mild and severe hypoxia. We found that CIH increased ET-ir in the CB by ∼10-fold leaving ET-1 plasma levels unchanged. Application of ET-1 to control and CIH-treated CBs produced long-lasting dose-dependent increases in f{hook} x, although the dose-response curve showed a rightward-shift in the CIH-treated CBs. CIH increased baseline f{hook} x and hypoxic chemosensory responses, which were reduced by 50 μM bosentan in CBs from CIH-treated cats. Present results suggest that a local increase of ET-1 in the CB may contribute to the enhanced chemosensory responses induced by CIH predominantly through a vasomotor mechanism. © 2006 Elsevier B.V. All rights reserved.

Más información

Título según WOS: Contribution of endothelin-1 to the enhanced carotid body chemosensory responses induced by chronic intermittent hypoxia
Título según SCOPUS: Contribution of endothelin-1 to the enhanced carotid body chemosensory responses induced by chronic intermittent hypoxia
Título de la Revista: BRAIN RESEARCH
Volumen: 1086
Número: 1
Editorial: Elsevier
Fecha de publicación: 2006
Página de inicio: 152
Página final: 159
Idioma: English
URL: http://linkinghub.elsevier.com/retrieve/pii/S0006899306004987
DOI:

10.1016/j.brainres.2006.02.082

Notas: ISI, SCOPUS