Abstract
Erabutoxin B, a toxic protein obtained from venom of Laticauda semifasciata, exerted a blocking effect on frog nerve-muscle preparation. This toxin reduced the irritability of the muscle cell and decreased tension developing in response to direct stimulation. By indirect stimulation, the ‘effective time’ was linear to the concentration of erabutoxin B in the range of 10-5 to 10-6. In microelectrode study, both the action potential and endplate potential were found diminished by erabutoxin B. The resting membrane potential was not affected. The effective membrane resistance was decreased. The action of erabutoxin B was considered to be a summation of blocking at the presynaptic site and direct action on the muscle cell membrane.
