Involvement of Autonomic Nervous System in Antiarrhythmic Effect of Intermittent Hypobaric Hypoxia.

We studied the involvement of the autonomic nervous system in the antiarrhythmic effect of intermittent hypobaric hypoxia modeled by daily placing the rats into an altitude chamber at 405 mm Hg (5000 m above sea level). The antiarrhythmic effect of hypoxia was observed on the model of acute coronary occlusion/reperfusion in vivo, but not during simulation of total ischemia/reperfusion of the isolated myocardium. Intravenous injection of ganglionic blocker hexamethonium (30 mg/kg) 15 min prior to in vivo coronary occlusion modeling abolished the antiarrhythmic effect of intermittent hypobaric hypoxia, which suggests that this effect is mediated via activation of the autonomic nervous system.