Acute blood pressure elevation during repetitive hypocapnic and eucapnic hypoxia in rats

Fletcher. Acute blood pressure elevation during repetitive hypocapnic and eucapnic hypoxia in rats. J. Appl. Physiol. 82(4): 1071–1078, 1997.—Using a rat model, we investigated whether episodic eucapnic hypoxia was a more potent stimu-lus to acute blood pressure (BP) elevation and bradycardia than episodic hypocapnic hypoxia. We also investigated the role of sympathetic and parasympathetic nervous system in this cardiovascular response. Sprague-Dawley (SD) and Wistar Kyoto (WKY) rats were exposed to repetitive 30-s cycles of hypocapnic or eucapnic hypoxia before and after intravenous injection of the a1-adrenergic blocker prazosin, a2-adrenergic blocker yohimbine, or atropine. Eucapnic hyp-oxia caused a threefold elevation in systolic BP from baseline (83.5 6 3.5 mmHg in WKY, 70.6 6 4.6 mmHg in SD) an