Progesterone Protects against Hypoxic Ventilatory Depression in Male Rats
It has been suggested that a high level of progesterone facilitates the increase in ventilation during hypoxia in animals as well as in humans (1,2). Recently, Bayliss et al. reported that progesterone stimulates respiration through a central mechanism in anesthetized cat (3). However, there have been few studies concerning the mechanisms of action of progesterone on the ventilatory response to hypoxia. In this study, we sought to determine the effects of progesterone on hypoxic ventilatory depression as well as stimulation. We hypothesized that administration of progesterone, chlormadinone acetate (CMA), may protect the deterioration of respiratory function during hypoxia. To elucidate the possible site(s) of drug action, we also compared the ventilatory response to hypoxia before and after bilateral sectioning of the carotid sinus nerves, with or without administration of progesterone in the rat.
KeywordsVentilatory Response Peripheral Chemoreceptor Hypoxic Ventilatory Response Carotid Sinus Nerve Systemic Hypoxia
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