[Disulfide bonds in the cholinoreceptors of frog sympathetic ganglion neurons].

The effect of dithiotreitol (disulfide bonds reducing agent) and potassium ferricyanide (oxidative agent) on the nicotinic and muscarinic receptors of frog's sympathetic ganglion neurons were studied using intracellular electrodes. Dithiotreitol inhibited the responses evoked by carbachol, suberildicholine and 5-methylfurmethide. Ferricyanide if applied after dithiotreitol increased the inhibited responses to suberildicholine and decreased those to 5-methylfurmethide. Using protectors it was shown that both acetylcholine and tetramethylammonium protected nicotinic and muscarinic receptors from the action of dithiotreitol, the acetylcholine was more effective than tetramethylammonium in the case of nicotinic receptor. It was suggested that there are disulfide bonds in the active centres of nicotinic and muscarinic receptors located in the anionic centres as well as outside of those centres.