MEASUREMENTS OF CATECHOLAMINE-MEDIATED APOPTOSIS OF IMMUNOCOMPETENT CELLS BY CAPILLARY ELECTROPHORESIS

Single cell analysis with capillary electrophoresis, a technique capab le of detecting zeptomole quantities (10(-21) mole) of neurochemical s pecies, has been used to demonstrate that lymphocytes are capable of a ctive synthesis of dopamine and norepinephrine. Exposure of lymphocyte s to catecholamines at concentrations as low as 10 nM leads to decreas ed proliferation and differentiation, e.g. interferon-gamma (IFN-gamma ), interleukin-4 (IL-4) and immunoglobulin (Ig). In addition, both inh ibition of dopamine uptake with nomifensine and inhibition of packing of catecholamines into vesicles with tetrabenazine, results in signifi cantly lower levels of dopamine and norepinephrine (p < 0.01 and p < 0 .05, respectively). The catecholamine-dependent inhibition of T-and B- lymphocyte activity is mediated via an induction of a Bcl-2/Bax and Fa s/FasL involved apoptosis. These findings indicate a novel mechanism f or regulation of lymphocyte activity in the central nervous system, wh ereby elevated regional levels of catecholamines might lead to the imm unoprivilege of the brain.