The neuromuscular blocking effect of trimetaphan alone and in combination with different non-depolarizing muscle relaxants in the rat.

The effect of trimetaphan alone and in combination with pancuronium, tubocurarine or metocurine (dimethyl tubocurarine) has been examined on the rat phrenic nerve diaphragm preparation. Trimetaphan alone produced neuromuscular blockade in an all-or-none fashion once a concentration of between 2.39 X 10(-4) and 3.00 X 10(-4) M had been exceeded. Concentrations of trimetaphan below this threshold produced a dose-dependent potentiation of all three non-depolarizing relaxants studied. This potentiation was equal for tubocurarine and metocurine, but less for pancuronium.