Exposure of rodents to 30 min of restraint stress did not significantly affect the maximal binding site density [Bmax; t (6) = 1.10, p > 0.05; Table 2] or the binding affinity of [3H]CP55940 for the CB1 receptor [Kd; t (6) = 1.27, p > 0.05; Table 2]. Similarly, there was no effect of restraint stress on the maximal stimulation of CB1 receptor mediated GTPγS binding [t (6) = 0.53, p > 0.05; Table 2], but there was a trend for stress to increase the EC50 of WIN 55212-2, suggestive of reduced agonist sensitivity of the CB1 receptor to induce GTP exchange [t (6) = 1.94, p = 0.10; Table 2].
