The development of a method to measure [3H] dopamine uptake by washed platelets provides no evidence for circulating inhibitors of platelet dopamine uptake in schizophrenia.
Altered [3H] dopamine uptake by platelet-rich plasma (PRP) has been reported in some subjects with schizophrenia (Rotman et al 1980; Dean et al 1990). As platelet dopamine uptake was measured using PRP, it was not possible to determine if the changes in schizophrenia were intrinsic to the platelet or due to plasma factors. Furthermore, the constraints of plasma as a medium for platelet suspension has hindered the study of the physiological requirements of platelet dopamine uptake. A method is now reported that allows platelets to be suspended in a controlled medium while preserving the dopamine uptake mechanism of the platelet. Dopamine uptake by platelets in a controlled medium was dependent on temperature, energy, sodium, and chloride. Furthermore, plasma from subjects with schizophrenia and schizophreniform disorder did not significantly alter [3H] dopamine uptake by platelets compared to the effect of plasma from control subjects. Hence, these data provide no evidence for a circulating inhibitor of platelet [3H] dopamine uptake in plasma from subjects with schizophrenia.
Mental Health Research Institute of Victoria, Royal Park Psychiatric Hospital, Parkville, Australia.
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Sundram
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Dean
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Copolov
D001792:Blood Platelets / Q000378:metabolism*; D004298:Dopamine / Q000097:blood* / Q000493:pharmacokinetics; D006801:Humans; D066298:In Vitro Techniques; D012559:Schizophrenia / Q000097:blood*; D014316:Tritium
D014316:Tritium; D004298:Dopamine