ADRENOCEPTORS ON BLOOD-CELLS IN PATIENTS WITH PRIMARY HYPERTENSION - CORRELATION WITH BLOOD-PRESSURE AND RELATED VARIABLES

Objective: Alterations in platelet alpha2-adrenoceptor and mononuclear leucocyte beta2-adrenoceptor characteristics in primary hypertension have been extensively studied. The results of the reports have not bee n consistent, possibly because of the small number of subjects in most of the studies. We therefore studied the blood-cell adrenoceptor char acteristics in a relatively large group of primary hypertensive and no rmotensive subjects. Design: Platelet alpha2-adrenoceptor characterist ics were compared in 65 hypertensive and 51 normotensive subjects. Mon onuclear leucocyte beta2-adrenoceptor characteristics were compared in 72 hypertensives and 67 normotensives. Untreated hypertensive subject s were selected from the outpatient clinic and the normotensive contro ls were recruited by a newspaper announcement. Methods: Platelets and mononuclear leucocytes were isolated from blood samples obtained after at least 10 min supine rest. The alpha2- and beta2-adrenoceptor chara cteristics were determined with [H-3]-rauwolscine and [I-125]-(-)cyano pindolol, respectively. Correlations between the adrenoceptor characte ristics and clinical parameters of the subjects were studied. Results: No differences in alpha2- or beta2-adrenoceptor densities were observ ed between the two groups. However, a significantly lower equilibrium dissociation constant for [H-3]-rauwolscine was observed in the hypert ensive group. The correlations between the adrenoceptor characteristic s and clinical parameters were weak and mostly not statistically signi ficant. The results were compared with the most relevant studies in th e literature. Conclusions: From our study and the literature, we concl ude that blood-cell adrenoceptor characteristics are unchanged in prim ary hypertension.