Electrical response of glioma cells to acetylcholine.

A bromodeoxyuridine resistant mutant of rat gliom line C6 grown in the presence of N6,02'-dibutyryl adenosine-3':5'-cyclic monophosphate, although inexcitable by electrical current, responds to iontophoretic application of acetylcholine by slow hyperpolarization. The sensitivity to acetylcholine is strongly reduced by excessive amounts of acetylcholine. The hyperpolarization response is inhibited by atropine or alpha-bungarotoxin, but not by D-tubocurarine. In the absence of acetylcholine some cells display spontaneous hyperpolarizations at regular intervals. The membrane resting potential is decreased if the concentration of external K+ is raised.