TABLE 2.

Dissociation rates of the agonist radioligand [¹²⁵I]I-AB-MECA from WT and mutant receptors in the absence and presence of allosteric modulators

	Control	+ HMA (100 μM)	+DU124183 (10 μM)	+VUF5455 (10 μM)
WT	0.064 ± 0.007	0.028 ± 0.004	0.029 ± 0.005	0.025 ± 0.004
N30A1.50	0.160 ± 0.036	0.083 ± 0.028	0.148 ± 0.028	0.159 ± 0.024
D58N2.50	0.122 ± 0.017	0.064 ± 0.019	0.133 ± 0.026	0.122 ± 0.025
T94A3.36	0.062 ± 0.008	0.038 ± 0.006	0.041 ± 0.004	0.034 ± 0.007
H95A3.37	0.112 ± 0.011	0.070 ± 0.019	0.067 ± 0.021	0.055 ± 0.021
D107N3.49	0.028 ± 0.006	0.014 ± 0.004	0.030 ± 0.003	0.013 ± 0.005
K152AEL2	0.052 ± 0.005	0.028 ± 0.008	0.029 ± 0.009	0.027 ± 0.011
F182A5.43	0.079 ± 0.010	0.085 ± 0.014	0.079 ± 0.012	0.074 ± 0.016
W243A6.48	0.051 ± 0.008	0.027 ± 0.009	0.029 ± 0.002	0.031 ± 0.007
L244A6.49	0.120 ± 0.020	0.068 ± 0.007	0.068 ± 0.008	0.062 ± 0.006
S247A6.52	0.067 ± 0.006	0.035 ± 0.009	0.037 ± 0.008	0.035 ± 0.010
N274A7.45	0.085 ± 0.010	0.076 ± 0.019	0.079 ± 0.015	0.083 ± 0.013

The dissociation rates of [¹²⁵I]I-AB-MECA from N30A^1.50 and H95A^3.37 were determined at 4°C (to slow the dissociation rate to measurable levels), whereas WT and other mutant receptors were measured at 25°C. The concentration of [¹²⁵I]I-AB-MECA was 0.5 nM. Results were expressed as means ± S.E. from at least three experiments