Noradrenaline induces phosphorylation of ERK-2 in human peripheral blood mononuclear cells after induction of alpha(1)-adrenergic receptors

alpha(1)-Adrenergic receptors (ARs) are not expressed by peripheral blood m ononuclear cells (PBMCs) of healthy human individuals. However, in the pres ent study we show that alpha(1)-ARs can be induced in lymphocytes after cul turing with either the mitogen PHA or the glucocorticoid dexamethasone. Mor eover, incubation of these activated PBMCs with noradrenaline (NA) results in enhanced phosphorylation of ERK-2 a kinase involved in the activation of many immune functions. Similar induction of alpha(1)-AR mRNA with concomit ant NA-induced activation of ERK-2 occurs in monocytes after culture with L PS. Our results demonstrate that functional alpha(1)-ARs can be induced on PBMCs and that these alpha(1)-ARs mediate NA-induced activation of ERK-2. ( C) 2000 Elsevier Science B.V. All rights reserved.