The action of dantrolene sodium on the lobster neuromuscular junction

Abstract

1. At a concentration of 2.3 to 3.1 × 10 −5 M, dantrolene Na increased the frequency of stimulation required to elicit a visible muscle contraction from 7 stimuli/sec to a minimum of 25 stimuli/sec. 2. At the same concentration, dantrolene Na had no effect on the following pre- and post-synaptic parameters at the neuromuscular junction of the lobster: excitatory synaptic conductance, excitatory reversal potential, excitatory miniature end plate potential amplitude, excitatory quantal content per fiber, excitatory MEPP frequency, inhibitory synaptic conductance, or inhibitory reversal potential. 3. Resting input conductance was slightly, but consistently increased by dantrolene Na.