ROLE OF ENDOTHELIN-1 ON THE ENHANCED CAROTID BODY ACTIVITY INDUCED BY CHRONIC INTERMITTENT HYPOXIA

Abstract

The systemic ventilatory and cardiovascular adjustments to hypoxia depend on the activation of peripheral chemoreceptors, mainly the carotid bodies (CBs). Intermittent hypoxia produces CB chemosensory excitation, which may participate in the pathogenesis of obstructive sleep apnea (OSA) (Narkiewicz et al., 1999). Recently, we found that chronic intermittent hypoxia (CIH) for four days enhances cat ventilatory and chemosensory responses to acute hypoxia (Rey et al., 2004). We hypothesized that the enhanced chemosensory response to hypoxia induced by CIH would be the result of an increased effect of excitatory modulators, like endothelin (ETs) peptides, and/or a decreased effect of inhibitory molecules within the CB. Thus, we studied the contribution of ETs on the enhanced chemosensory response to hypoxia in CIH-treated cats.