Characterization of the Synaptosomal Dopamine Uptake in Studies with Postmortem Human Brain
Investigations in the neurochemical pathology of the cerebral dopaminergic systems in humans do not involve studies of the high-affinity DA uptake. This is possibly based on the relative rapid decline of DA uptake during postmortem storage in situ as well as its drastic decrease by tissue freezing in liquid nitrogen (below 20 % of controls). Therefore, binding studies with 3H cocaine were recently proposed as a reliable probe for the DA uptake complex (Pimoule et al., 1983). On the other hand, we investigated the kinetic parameter of the synaptosomal high-affinity DA uptake (Hetey and Quiring, 1980; 3H DA: 0.02 – 0.1 µm in the incubation buffer, Lineweaver-Burk analysis of 37° – 0°C values). The DA uptake was measured after freezing of brain pieces in the presence of dimethylsulfoxide (DMSO), after postmortem storage in situ and in some postmortem brain of schizophrenia patients.