1982 Volume 32 Issue 5 Pages 727-740
The facilitatory action of tetraethylammonium (TEA) on endplate potentials (EPPs) and its depression by streptomycin (SM) were analyzed by recording EPPs from curarized frog muscles using conventional microelectrode techniques. The fractional release of transmitter was estimated from the early tetanic rundown of EPP during short train stimuli. To explain the marked facilitatory effect of TEA, on the fractional release and the antagonistic interaction of SM thereupon, it was postulated that to increase the evoked transmitter release, two molecules of TEA react with two sites in a still unidentified Casensitive component X of the transmitter-releasing mechanism. SM depresses the evoked transmitter release by competing with TEA for the occupancy of one of the two TEA sites. The equations derived from the present assumptions agreed reasonably well with the experimental results.
