Validation of a method to measure the uptake of [3H]dopamine by human platelets.
We have assessed the validity of using platelet-rich plasma (PRP) to measure dopamine uptake by platelets. In addition, we report on a pilot study comparing [3H]dopamine uptake by PRP from psychotic patients to that by PRP from healthy volunteers. Uptake of radiolabelled dopamine by PRP was related to the concentration of [3H]dopamine added and correlated with platelet number. [3H]dopamine uptake by PRP was not altered by varying pH (6.8 to 8.0) or by the time PRP was incubated prior to the addition of the radiolabelled dopamine. 11.7 +/- 0.34% (mean +/- SEM) of [3H]dopamine added to plasma was precipitated by polyethylene glycol (PEG) and appeared to be associated with a large molecular mass component of plasma. The amount of PEG precipitable [3H]dopamine did not correlate with dopamine uptake (r = 0.02) or differ between patients and controls. Uptake of [3H]dopamine by PRP from 52 volunteers (26 M, 26 F; age, 18-75 yr), expressed as the area under the dopamine uptake curve up to 60 min in arbitrary units, ranged from 72-285 for males and 59-455 for females. Comparing [3H]dopamine uptake by PRP from 15 psychotic patients to these sex-specific reference ranges 9 of 13 PRP from schizophrenic patients had [3H]dopamine uptake outside the normative values whereas the two non-schizophrenic patients did not differ from normal. Dopamine uptake by PRP may be useful in the study of diseases with altered dopaminergic activity in the CNS.
Dean
B
B
Mental Health Research Institute of Victoria, Parkville, Australia.
Kulkarni
J
J
Copolov
D L
DL
D000293:Adolescent; D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D003866:Depressive Disorder / Q000378:metabolism; D004298:Dopamine / Q000097:blood / Q000378:metabolism*; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010976:Platelet Count; D012016:Reference Values; D012559:Schizophrenia / Q000378:metabolism*; D013997:Time Factors
D004298:Dopamine