DIAZEPAM DECREASES THE RESPONSE TO THE ELECTRICAL-STIMULATION OF THE NERVE-SKIN PREPARATION OF THE TOAD CAUDIVERBERA-CAUDIVERBERA

1. The effect of diazepam was examined in the nerve skin preparation o f the toad Caudiverbera caudiverbera. 2. Nerve stimulation was followe d immediately by a transient increase in short-circuit current (SCC) a nd in the potential difference (PD), which consisted of a rapid and th en a slow component. 3. Diazepam concentrations from 5.0 x 10(-5)M to 5.1 x 10(-4)M caused a dose-dependent block of both components to a 30 % of their control values and also reduced the stimulatory responses t o noradrenaline in this preparation. 4. Diazepam antagonized the potas sium blocking effect of barium. 5. These results, based on electrophys iological and pharmacological evidence, are consistent with a calcium and sodium blocking effect of diazepam on the nerve skin junction of C . caudiverbera.