Transmitter Release During Repetitive Stimulation: Selective Changes Produced by Sr 2+ and Ba 2+

Abstract
The addition of Sr 2+ or Ba 2+ to the solution bathing the frog neuromuscular junction leads to an increased release of transmitter by each nerve impulse during and following repetitive stimulation. The mechanisms by which Sr 2+ and Ba 2+ increase release are not the same. Each ion appears to act selectively on a different process involved in transmitter release.