Modulation of lymphocyte adrenergic receptors and transformation responses by therapeutic drugs

Lymphocyte transformation responses and adrenergic receptor (adrenoceptor) binding have been studied in the presence of therapeutic drugs. Chloroquine, propranolol and trifluoperazine were the most potent drugs investigated, inhibiting lymphocyte responses and the binding of adrenergic antagonists at 10(-5)M. Drugs such as salicylate and chlorpropamide, with little affinity for adrenoceptors but with a high capacity for binding to albumin, inhibited lymphocyte transformation at 10(-3)M; probably by displacing protein-bound ligands with an affinity for adrenoceptors. Metronidazole and allopurinol had no significant effect on lymphocyte transformation, or on adrenoceptor antagonist binding at 10(-3)M. Adrenoceptor affinity or receptor numbers and lymphocyte responses were increased by non-inhibitory concentrations of most drugs. We conclude that most drugs modify lymphocyte responses by interacting directly or indirectly with adrenoceptors. This modulation of adrenoceptors may have important implications, relating to the induction and control of asthma by drugs.