Functional and phenotypic changes in polymorphonuclear neutrophils induced by catecholamines

Purpose. To elucidate differential functional and phenotypic changes in response to relevant catecholamines, the generation of oxidative free radicals by PMN, and changes in the expression of L-selectin and Mac-1 on the surface of PMN were examined in the presence of epinephrine, norepinephrine and dopamine in physiological and pharmacological concentrations. Materials and methods. Human polymorphonuclear neutrophils were obtained from healthy donors and pretreated with 0.5 nM or 500 nM epinephrine; 1.18 nM or 1180 nM norepinephrine; or 0.26 nM or 261 nM dopamine, followed by stimulation with FMLP. Stimulated neutrophils were incubated with antibiodies against CD 11 b or CD 62 l and assessed by flow cytometry. Additional probes were assessed by flow cytometry for the generation of oxidative free radicals. Results. All catecholamines in high concentration inhibited the suppression of CD 62 l expression and CD 11 b upregulation following stimulation with FMLP. A high concentration of epinephrine suppresses generation of oxidative free radicals. Conclusions. The effect of catecholamines on the expression of CD 62 l explains the increased expression of L-selection on PMN observed after trauma. The suppression of CD 11 b reduces leukocyte adherence and consecutive abnormalities in microvascular flow. Epinephrine inhibits the generation of oxidative free radicals by PMN with potentially detrimental effects with respect to bacterial clearance.