Abstract
OBJECTIVE: To study the effect of pantoprazole on neuromuscular transmission and its interactions with vecuronium at the neuromuscular junction (NMJ). MATERIALS AND METHODS: Effect of pantoprazole on neuromuscular transmission (2 muM - 16 mM) and reversal of neuromuscular blockade by pantoprazole and vecuronium with neostigmine (3.3 muM), 3,4-diaminopyridine (0.25 mM), KCl (6 mM), and CaCl(2) (10 mM) were studied by the indirect and direct stimulated preparation of rat phrenic nerve hemidiaphragm. Cumulative reponse curves (CRC) of vecuronium (1 muM to 32 muM) were studied in the absence and presence of 32 muM, 64 muM, and 128 muM pantoprazole. Time for head drop by vecuronium infusion was recorded in the absence and presence of acute and chronic administration of pantoprazole (1.9 mg/kg) in rabbits. RESULTS: Pantoprazole potentiated the basal contractile twitch responses at a lower concentration followed by neuromuscular blockade at a higher concentration. The neuromuscular blockade was not reversed by neostigmine (3.3 muM), 3,4-diaminopyridine (0.25 mM), KCl (6 mM), and CaCl(2) (10 mM). Pantoprazole potentiated the vecuronium-induced neuromuscular blockade. It decreased the total time for complete blockade in rat phrenic nerve hemidiaphragm preparation (P < 0.05) and decreased the time for the head drop in rabbits with vecuronium infusion (P < 0.0001). CONCLUSION: Pantoprazole has a direct neuromuscular blocking action. It has the potential to interact with vecuronium.