Receptor Function and Ion Transport in Turkey Erythrocytes

Abstract

Publisher Summary This chapter focuses on the identification of the β-adrenergic receptor in the turkey erythrocyte and examination of activation of adenylate cyclase, generation of cyclic adenosine monophosphate (cAMP) and enhanced ion transport in these cells because of the interaction of β-adrenergic catecholamines with the receptor. It further discusses the regulation by guanine nucleotides. Guanine nucleotides modulate the response of adenylate cyclase to catecholamines in avian erythrocytes and in a variety of other hormonally responsive tissues. In general, the guanine nucleotides augment the response to hormones in adenylate cyclase systems. In the turkey erythrocyte plasma membrane, 5’-guanylylimidodiphosphate [Gpp(NH)p) markedly enhances catecholamine-stimulated adenylate cyclase activity. The chapter then reviews the effects of β-adrenergic catecholamines on ion transport. It summarizes the effects of ouabain on ion transport and cAMP in turkey erythrocytes. In turkey erythrocytes, the refractoriness to cAMP and its relief by ouabain reflect an ouabain-inhibitable depletion or inactivation of a substance that is required for the effect of the cyclic nucleotide or an ouabain-inhibitable accumulation or activation of a substance that reduces the effect of cAMP. The observations that both ouabain and cAMP alter ion fluxes in turkey erythrocytes and that ouabain can potentiate and prolong the effect of cAMP. This suggests that the mechanism through which these two agents exert their effects at some point can share a common biochemical pathway.