Effect of sodium nitroprusside on the biophase concentration of C-tubocurarine at the neuromuscular junction

D-Tubocurarine (DTC) at an intravenous dose of 250 mu g/kg, or at an intra-arterial dose of 25 mu g/kg, produced about a 50% block on the twitch tension of the indirectly stimulated tibialis anterior muscle of anaesthetized cats. Results indicate that the biophase concentration of DTC at the veuromuscular junction may be decreased as a consequence of the vasodilation induced by sodium nitroprusside leading to a reduced transport of the blocker to the site of action.