Ventilatory Responses to Histotoxic Chemostimulation in Hypoxia Adapted Rats

Abstract

Rats adapted to prolonged hypobaric hypoxia present a blunted hypoxic ventilatory response (HVR) when stimulated by steady state (Wach et al, 1989) or transient acute hypoxia (Lagneaux & Lecomte, 1991) The origin of this post-acclimatization blunted HVR remains controversial Central or peripheral mechanisms, alone or in association must be investigated. In large animals, the site of inhibition can be detected by comparison between simultaneous recordings of carotid sinus nerve activity and ventilatory responses to the hypoxic stimulus. This technique is difficult to manage in the rat and an alternative approach must be used to identify the site of the blunted mechanism: glomic chemosensitivity or transduction at central level