Neuroblastoma membranes inhibit isoproterenol-stimulated rise of cAMP in glioma cells.

Abstract

C6 glioma cells respond to beta-adrenergic agonists (isoproterenol) with a transient rise in intracellular cyclic adenosine monophosphate level. This beta-responsiveness of C6 cells is inhibited by the presence of a plasma membrane fraction, which has a five- to six-fold purification of membrane markers, showed a greater inhibition of beta-responsiveness in C6 cells than any other subcellular fractions of B104 cells. The inhibitory effector(s) is apparently associated with integral membrane structure(s) since ionic extraction and treatment with chelating agents did not remove the effect from the particulate membrane fraction. The effector is probably proteinaceous in nature as judged by its susceptibility to inactivation by heat and protease treatment. The data indicate that neither adenylate cyclase nor phosphodiesterase enzyme is likely to be directly involved in mediating the beta-nonresponsiveness of C6 cells.