Acceleration by stannous ion of the evoked release of transmitter from motor nerve endings in the frog

Abstract

Stannous ion (Sn 2+, 30μM) increased the amplitude of endplate potential (EEP) in the frog sartorius muscle, although the amplitude of miniature endplate potential (MEPP) or acetylcholine potential evoked by iontophoretic application of acetylcholine was unchanged. Sn 2+ (10–100 μM) dose-dependently increased the quantal content of the EPP. MEPP frequency was not altered by 30 μM Sn 2+. These findings indicate that Sn 2+ may increase the EPP as a result of acceleration of the transmitter release evoked by nerve impulses.