Ebselen prevents the carotid body chemosensory potentiation and reverses the hypertension induced by intermittent hypoxia (873.1)

Abstract

Oxidative stress is associated with hypertension and enhanced carotid body (CB) chemosensory responses induced by chronic intermittent hypoxia (CIH), but the underlying mechanism is not fully understood. We tested if ONOO‐ is involved in the CB enhanced chemosensivity. Accordingly, we studied the effects of Ebselen, a specific ONOO‐ scavenger, on 3‐nitrotirosine immunoreactivity (3‐NT‐ir) in the CB, the chemosensory discharge and arterial blood pressure (BP) in rats exposed to CIH. Male Sprague‐Dawley rats were exposed to CIH (5% O2, 12 times/h, 8 h/day), BP was measured with telemetry and Ebselen was administrated using subcutaneous osmotic pumps (10 mg/Kg day). At the end of the experiments, CB chemosensory discharge was recording, and rats were perfused with parafolmaldehyde 4% for 3‐NT‐ir. CIH increased 3‐NT‐ir in the CB, enhanced the chemosensory responses to hypoxia, elevated BP during normoxia and potentiated the BP responses to hypoxia. Ebselen prevented the CIH‐induced CB chemosensory potentiation, and reversed the elevated BP and the potentiated pressor responses to hypoxia. Our results showed that 3‐NT formation caused by CIH, contributes to the CB chemosensory potentiation, and that ONOO‐ is involved in the CIH‐induced hypertension.Grant Funding Source: Supported by FONDECYT 1100405