In vitro Activation of Human and Rat Lymphocyte and Macrophage Functions by Norepinephrine

Norepinephrine (NE) has been associated not only with increasing blood pressure, atherosclerosis, heart disease, and other life threatening conditions, but also with altering immune responses by influencing leukocyte functions. In the present study, we evaluated the in vitro effects of NE on rat thymic lymphocyte and human peripheral blood mononuclear cells (HPBMC) functions. We observed that NE marginally, but significantly (P < 0.01) enhanced (1.3-fold increase) proliferation of rat thymic lymphocytes at 10^-5 M, without altering HPBMC proliferation, as compared with untreated control. In addition, NE (10^-5 M) significantly (P < 0.01) enhanced nitric oxide production (2.9 + 0.095 nmol/well) (which reduced 20% cell viability), and stimulated (P < 0.01) TNF-α production (4 + 0.16 pg/ml) by rat macrophages. NE (10^-5 M) was also observed to induce 2-fold increase in mRNA signal of TNF-α, and stimulated that of IL-1 and IL-6 by HPBMC, as compared with untreated control. Taken together, these results indicated that NE was capable to activate in vitro rat and human lymphocyte and macrophage pro-inflammatory response.