Correlation between lymphocyte beta 2-adrenoceptor density and mean arterial blood pressure: elevated...

In 41 normotensive volunteers (diastolic pressure, less than 90 mm Hg) the beta 2-adrenoceptor density in lymphocytes was determined by (+/-)-125 iodocyanopindolol (ICYP) binding and compared with that in nine patients with borderline hypertension (diastolic pressure, 90-95 mm Hg) and 45 patients with established essential hypertension (diastolic pressure, greater than 95 mm Hg). The mean number of beta 2-adrenoceptors for controls was 774 +/- 49 (range, 300-1,500) ICYP binding sites/cell. In borderline hypertension it was significantly higher, with 1,037 +/- 22 (range, 950-1,150) sites/cell, and increased further in patients with essential hypertension to 1,424 +/- 72 (range, 700-2,700) sites/cell. The KD values for ICYP, however, were nearly the same in all groups (approximately 50 pM). Calculation of the data of all 95 subjects resulted in a significant positive correlation between beta 2-adrenoceptor density and mean arterial blood pressure (r = 0.637; p less than 0.001). Since the properties of beta 2-adrenoceptors in human lymphocytes resemble those in other tissues, the hypothesis is presented that the increased density of beta 2-adrenoceptors may reflect sympathetic hyperactivity in essential hypertension, which might contribute (perhaps via enhanced release of endogenous noradrenaline through stimulation of presynaptic beta 2-adrenoceptors by adrenaline) to the elevation of blood pressure.