Active [3H]-dopamine uptake displayed by native lymphocyte suspensions is mainly due to contaminating platelets.
Kinetic and pharmacologic properties of specific [3H]-dopamine uptake by native human lymphocytes were investigated. Our results suggest that uptake of [3H]-dopamine measured with lymphocytes after separation over Ficoll-Paque or Percoll is mainly caused by platelets which are always part of freshly prepared lymphocyte suspensions. The investigations were extended to well-defined cell lines in order to compare the pharmacological properties of native and immortalized cells regarding the uptake of [3H]-dopamine without any influence of contaminating cells such as platelets. Using the human neuroblastoma cell line IMR32 we demonstrate a GBR-12909 and cocaine-sensitive specific uptake of dopamine, whereas dopamine uptake in platelets is performed by an imipramine-sensitive serotonin transporter. Blood-derived stable cell lines (MOLT-3 and EBV-transformed B-lymphocytes) exhibited no [3H]-dopamine uptake. The view that specific [3H]-dopamine uptake on native human lymphocytes is mainly caused by platelets and not specific for lymphocytes is supported by the finding that homogenous B- and T-lymphoblastoids (MOLT-3 and EBV-transformed B-lymphocytes) exhibited no comparable uptake.
Krieger
K
K
Department of Psychiatry, University of Düsseldorf, Germany.
Klimke
A
A
Henning
U
U
D001792:Blood Platelets / Q000378:metabolism*; D002461:Cell Line, Transformed; D002469:Cell Separation; D004298:Dopamine / Q000378:metabolism*; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D014316:Tritium
D014316:Tritium; D004298:Dopamine