The efflux of nor-epinephrine from platelets in essential hypertension

The precise role of sympathetic nervous system in initiation and/or maintenance of essential hypertension is unclear even today. Platelets have been used as a suitable model for studying neuronal turnover of biogenic amines. The present study comprised of hypertensive subjects (23) and normotensive controls (10). Hypertensive subjects exhibited significantly enhanced norepinephrine efflux from platelets at both 30 minutes and 60 minutes (p less than 0.001). The percent norepinephrine efflux from platelets correlated with diastolic (r = 0.66 and 0.76) and mean arterial blood pressure (r = 0.54 and 0.65) but not with systolic blood pressure. The norepinephrine efflux rate (K) similarly correlated with diastolic and mean arterial blood pressure in hypertensive subjects studied. From the above findings it appears that operative sympathetic nervous system activity is enhanced in essential hypertension. The enhanced efflux of norepinephrine from platelets may also indicate activated state of platelets in hypertension. Both could be important in genesis and complications of essential hypertension.