Figure 9

The influence of tBHP on allosteric regulation of M3 muscarinic receptors expressed in CHO cells is illustrated. a The dissociation of [³H]MS was measured by incubating CHO-M3 cell membranes with 1 nM [³H]MS for 1 hour before adding an excess of atropine (10 μM) to block the forward binding reaction. The off rate was measured in the absence (circles) and presence (triangles) of 10 μM gallamine in control (open symbols) or tBHP-exposed (2 mM 90 min) cells (closed symbols). Dissociation rate constants are listed in Table 1. b Similar responses in CHO cells expressing human M2 muscarinic receptors are shown. M2 receptors were examined because they typically display a more pronounced allosteric effect.