MAP kinase activation by mu opioid receptor in cord blood CD34(+)CD38(-) cells.

Objective: Opioid receptor expression and function traditionally have been studied in neuronal cells and recently in mature lymphoid cells; however, little is known about their possible functions in hematopoietic stem cells (CD34(+) cells). We studied the expression of the mu receptor on CD34(+) cells and assessed the signal transduction cascade it induces.

Materials And Methods: Mu-receptor expression on cord blood (CB) and peripheral blood (PB) CD34(+) cells was studied by microarrays, immunostaining, and fluorescence-activated cell sorting analysis.