Figure 2. Representative competitive displacement of3H-QNB by neuromuscular relaxants in membranes prepared from Chinese hamster ovary cells expressing the M2muscarinic receptor.3H-QNB (0.18 nM; 3.6 x Kdof M2receptor) was incubated with increasing concentrations of neuromuscular relaxants. Pancuronium had the highest affinity for the M2muscarinic receptor compared with rocuronium, mivacurium, pipecuronium, and doxacurium (top), and succinylcholine, atracurium, and gallamine (bottom).