Plasma catecholamine modulation of alpha 2 adrenoreceptor agonist affinity and sensitivity in normotensive and hypertensive human platelets.

摘要: We measured alpha 2-adrenoreceptor density as well affinity for and sensitivity to agonist on intact platelets of normotensive hypertensive subjects before after physiological increases in plasma catecholamines. In normotensives, posture-induced rises catecholamines correlated with reduced fewer high state receptors. Platelet aggregation inhibition adenylate cyclase by L-epinephrine also was reduced. Hypertensive had similar upright posture, but showed no change receptor or sensitivity. No platelet number occurred these studies. vitro incubation revealed that from hypertensives slower desensitization than those normotensives. Binding studies at different temperatures varying sodium concentrations found thermodynamic sodium-dependent differences between groups. These demonstrate exhibit a defect the ability desensitize 2-adrenoreceptor.