Down‐regulation of β‐adrenergic receptors induced by mitogen activation of intracellular signaling events in lymphocytes

Abstract

The expression of β‐adrenergic receptors on murine lymphocytes stimulated with concanavalin A was studied. A decrease in β‐adrenoceptor number on T lymphocytes and a diminished response to specific agonist stimulation at the peak of proliferation was found. The blockade of cell proliferation by tyrosine kinases or protein kinase C inhibitors reversed the decrease in β‐adrenoceptor number. PMA plus ionophore or interleukin‐2 but not PMA alone were able to induce β‐adrenoceptor downregulation accompanying cellular proliferation. These results showed that the intracellular signals triggered during lymphocyte activation are involved in β‐adrenoceptor down‐regulation and it would represent the loss of a mechanism that exerts negative neuroimmune control of cellular proliferation.