Table 3

Competition binding assay results using the antagonist radioligand and assuming two populations of binding sites

AgonistsKiKiHKiL% H of All Sites
nM nM nM
(R)-Epinephrine361  ± 3827.5  ± 4.6659  ± 12520  ± 9
(R)-Norepinephrine1,650  ± 3300.44  ± 0.064,400  ± 42030  ± 5
(S)-Norepinephrine7,130  ± 801,000  ± 43017,200  ± 50031  ± 2
UK-14,30413.0  ± 0.570.68  ± 0.0236.9  ± 1.0041  ± 2
p-Aminoclonidine20.7  ± 0.665.5  ± 0.23118  ± 3255  ± 6

Two-site models were statistically significantly superior (p < 0.05), compared with one-site fits for the agonists listed in this table but not for the other agonists included in Table 2.

    • H, high-affinity agonist binding sites; L, low-affinity agonist binding sites.