REVERSAL OF GUANETHIDINE BLOCKADE OF SYMPATHETIC NERVE TERMINALS BY TETRAETHYLAMMONIUM AND 4‐AMINOPYRIDINE

Abstract

The effect of tetraethylammonium (TEA) and 4‐aminopyridine (4‐AP) on the inhibitory effect of guanethidine on noradrenaline (NA) release was investigated in the perfused spleen of the cat. Guanethidine blocked the release of NA evoked by nerve stimulation. TEA and 4‐AP readily reversed this inhibitory effect, and the NA output was nearly doubled after repeated stimulation of the nerves. On subsequent perfusion with Krebs solution without TEA or 4‐AP, the inhibitory effect of guanethidine reappeared The reversal of guanethidine blockade of sympathetic nerves by TEA and 4‐AP is discussed.