Decreased number of alpha-adrenergic receptors in platelets of patients on maintenance haemodialysis.

In patients on maintenance haemodialysis the number of platelet alpha 2-adrenergic receptors, as assessed by 3H-yohimbine binding, was significantly lower than that in healthy volunteers. Responses to alpha 1-adrenergic receptor stimulation, determined by increases in systolic blood pressure produced by intravenous injections of phenylephrine, were also diminished in chronic haemodialysis patients. Thus, reduced sympathetic activity often observed during chronic haemodialysis treatment may be due to reduced number and/or sensitivity of alpha 1- and alpha 2-adrenergic receptors.