Table 3

Correlation between pK_b values of antagonists at the presynaptic α₂-autoreceptors in human neocortex and pK_d values at previously subclassified α₂ sites

Previously Subclassified α₂-Site	r(P Value)	Slope	No. of Antagonists
A. Native α₂ radioligand binding sites
α_2A, HT29 cells^3-a	0.97 (0.0000)	1.06	9
α_2B, neonatal rat lung^3-a	0.45 (0.2274)	0.39	9
α_2C, OK cells^3-a	0.88 (0.0016)	1.00	9
α_2D, bovine pineal gland^3-b	0.85 (0.0068)	0.86	8
B. Radioligand binding sites in COS cells transfected with α₂ genes
α_2A, human α2-C10^3-c	0.96 (0.0028)	1.12	6
α_2B, human α2-C2^3-c	0.44 (0.3812)	0.35	6
α_2C, human α2-C4^3-c	0.59 (0.2208)	0.54	6
α_2D, rat α2-RG20^3-d	0.78 (0.0354)	0.67	7
C. Other presynaptic α₂-autoreceptors
α_2A, rabbit brain cortex^3-e	0.90 (0.0023)	0.95	8
α_2A, rabbit atria^3-f	0.93 (0.0003)	0.91	9
α_2A, human kidney^3-e	0.98 (0.0001)	1.05	7
α_2A, pig brain cortex^g	0.95 (0.0012)	1.20	7
α_2D, guinea-pig brain cortex^3-e	0.81 (0.0150)	0.95	8
α_2D, guinea-pig atria^3-e	0.84 (0.0046)	0.89	9
α_2D, guinea-pig uretra^3-e	0.90 (0.0023)	1.04	8
α_2D, mouse brain cortex^h	0.79 (0.0113)	0.82	9

Shown are correlation coefficients (r), P values indicating the significance of the difference between r and 0, and slopes of the regression “pK_d at previously subclassified α₂ sites” on “pK_b at α₂-autoreceptors in human neocortex.” pK_b values at α₂-autoreceptors in human neocortex are from Table 2.pK_d values at previously subclassified α₂ sites are from the references quoted.

↵3-a Blaxall et al. (1991).
↵3-b Simonneaux et al. (1991).
↵3-c Bylund et al. (1992).
↵3-d O'Rourke et al. (1994).
↵3-e Trendelenburg et al. (1997).
↵3-f Limberger et al. (1995a).
^g,h Limberger et al. (1995b).