Table 1

Equilibrium cannabinoid receptor binding in membranes from various rat brain regions

Region	K_D
Region	[³H]SR141716A	[³H]WIN 55212-2
	nM
Frontal cortex	0.305 ± 0.142	4.58 ± 1.39	a
Cerebellum	0.190 ± 0.008	4.67 ± 0.58	a
Hippocampus	0.367 ± 0.112	2.76 ± 0.25	a
Striatum	0.388 ± 0.083	3.44 ± 0.27	a
Sensomotor cortex	0.209 ± 0.018	2.89 ± 0.22	a
Thalamus	0.224 ± 0.011	4.21 ± 0.49	a
Colliculi	0.302 ± 0.057	9.19 ± 0.61	b
Brainstem	0.257 ± 0.042	4.84 ± 0.89	a
Amygdala	0.145 ± 0.017	2.58 ± 0.57	a
Hypothalamus	0.134 ± 0.012	3.02 ± 0.15	a

	B_max
	[³H]SR141716A		[³H]WIN 55212-2
	pmol/mg
Frontal cortex	5.29 ± 0.45	ab	4.02 ± 0.78	bc
Cerebellum	5.27 ± 0.33	ab	5.50 ± 0.54	ab
Hippocampus	5.60 ± 0.47	a	5.22 ± 0.32	ab
Striatum	6.85 ± 0.65	a	6.17 ± 0.57	a
Sensomotor cortex	2.61 ± 0.24	c	2.42 ± 0.34	ce
Thalamus	2.74 ± 0.30	c	1.23 ± 0.15	e
Colliculi	2.79 ± 0.30	c	1.85 ± 0.12	de
Brainstem	2.47 ± 0.43	c	2.14 ± 0.32	ce
Amygdala	3.25 ± 0.23	bc	3.79 ± 0.10	bc
Hypothalamus	2.48 ± 0.36	c	3.51 ± 0.34	bcd

Cannabinoid receptor [³H]SR141716A (antagonist) and [³H]WIN 55212-2 (agonist) binding were conducted as described under “Materials and Methods.” The data represent mean values ± S.E.M. from saturation binding analyses which were conducted in triplicate three or more times in membranes from each region of rat brain. By the Tukey-Kramer HSD test at P < .05, values within a given column that are not significantly different are denoted by the same single letter. For the K _D values of [³H]SR141716A binding, none of the values are significantly different.