Platelet alpha 2 adrenoceptors in Parkinson's disease: decreased number in untreated patients and recovery after treatment.
[3H]-yohimbine binding sites were quantified in platelets from Parkinsonians with no clinical signs of dysautonomia. Never-treated Parkinsonians had a lower specific binding than control subjects. This alteration was associated with decreased epinephrine-induced platelet aggregation. Treatment with dopaminergic agents induced a significant increment of [3H]-yohimbine binding sites. These results show that Parkinson's disease is associated with a reduced number of peripheral alpha 2 adrenoceptors and that dopaminergic agents induce partial recovery.
D000368:Aged; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D001971:Bromocriptine / Q000627:therapeutic use; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood* / Q000188:drug therapy; D010974:Platelet Aggregation / Q000187:drug effects; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000378:metabolism*; D015016:Yohimbine / Q000097:blood
D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D001971:Bromocriptine; D007980:Levodopa