Control of the Production of Oxygen Intermediates of Human Polymorphonuclear Leukocytes and Monocytes by B-Adrenergic Receptors

Abstract

The control by R-adrenergic receptors of the production of oxygen radicals by zymosan-stimulated human polymorphonuclear leukocytes (PMN) and monocytes (Mψ) was studied in vitro by means of chemiluminescence. In addition we asked whether PMN Mpsi; exhibit differential sensitivity to β-adrenergic stimulation. Eor β-adrenergic stimulation we applied fenoterol ranging from 10⁻⁹ to 10 M × 2.7. We found a dose-dependent suppression of the production of oxygen radicals, the ID50 being approximately 10⁻⁶ M both for PMN and Mpsi;. By assessment of lactic dehydrogenase release a cytotoxic effect of the drug could be ruled out. When incubated together with the β-adrenergic antagonist propranolol at 10⁻⁶ and 10⁻⁷ M the suppressive effect of fenoterol could be reversed in dose-dependency. Preincubation with fenoterol revealed that the inhibitory action on Mpsi; persisted, in contrast, no such suppression could be verified with PMN. Our findings indicate the control of the production of oxygen intermediates of human PMN and Mpsi; by β-adrenergic stimulation. Furthermore, selective functional modulation of resting PMN and Mpsi; by β-adrenoceptors is suggested. These effects may be of importance in vivo, in particular since fenoterol was applied in pharmacological doses.