Fig. 5. Neuromuscular blocking agents' ability to block vagal nerve stimulation (VNS)–induced bradycardia by M2 muscarinic receptor antagonism expressed as a percentage of baseline induced bradycardia. (  A ) Within clinically relevant doses, pancuronium potently attenuated vagal nerve–induced bradycardia (#  P < 0.05 compared with baseline; n = 3), and mivacurium also attenuated vagal nerved induced bradycardia, but only at very large doses (#  P < 0.05 compared with baseline; n = 6), whereas vecuronium was without effect at all concentrations evaluated (  P > 0.05; n = 6). (  B ) Gallamine potently inhibited vagal nerve induced bradycardia within clinically relevant concentrations (#  P < 0.05 compared with baseline; n = 6). Rocuronium was without effect except at supraclinical concentrations (#  P < 0.05 compared with baseline; n = 10). (  C ) Within clinically relevant doses, rapacuronium potently inhibited vagal nerve–induced bradycardia (n = 9), whereas cisatracurium was without effect (#  P < 0.05 compared with baseline; n = 6). ↓= Human intubating dose.