Diaspirin Crosslinked Hemoglobin (DCLHb^TM): Control of Pressor Effect with Anti-Hypertensive Agents

Abstract

Diaspirin crosslinked hemoglobin (DCLHb TM) administration elevates mean arterial pressure (MAP). The purpose of this study was to determine whether commonly used antihypertensive agents could control this pressor effect in rats. Awake rats were injected intravenously (iv) with 280 mg/kg of DCLHb. Fifteen minutes later when MAP was 25–30% above baseline and heart rate (HR) was reciprocally decreased, prazosin (2 mg/kg;an alpha adrenergic blocker), nitroglycerine (NTG; 10–150 mcg/min; a nitrovasodilator), nicardipine (0.204–0.08 mg/hr; a calcium channel blocker) or labetalol (5 mg/kg; an alpha/beta adrenergic blocker) was administered iv. All four classes of antihypertensive agents promptly restored MAP to baseline. Coincident with the return of MAP to baseline, HR was restored to baseline in prazosin and NTG treated animals, however, bradycardia persisted in those animals treated with nicardipine and labetalol, most likely due to the negative chronotropic properties of these agents. We conclude that the pressor effect of DCLHb can be readily controlled with at least four different classes of commonly used antihypertensive agents.