| Abstract: | The authors analyzed the density of beta 2-adrenoreceptors, their affinity for catecholamines and activity of peripheral lymphocyte adenylate cyclase in healthy donors and patients with frequent ventricular premature contraction (VPC) in their pretreatment state and during short-term ethmosine or allapinine therapy. The density of beta 2-adrenoreceptors was increased by 43%, whereas guanylimidodiphosphate- or forskolin-induced stimulation of adenylate cyclase was decreased in the lymphocytes of VPC patients as compared to those of healthy donors. Ethmosine therapy failed to produce any changes in the density and affinity of the receptors for catecholamines. Allapinine caused a 47% reduction in beta 2-adrenoreceptor density and a 10(2)-10(3)-fold decrease in receptor affinity for 1-isoproterenol. After discontinuation of allapinine, the changes in beta 2-adrenoreceptor density and affinity for catecholamines remained on days 3 and 7, respectively. The clinical effect of both ethmosine and allapinine was accompanied by an increase in lymphocyte adenylate cyclase activity. |
