TABLE 1

Affinity values and percentage of binding sites for α1-adrenoceptor antagonists in SMG-C10 cells and submandibular glands The values are mean ± S.E.; n, number of separate SMG-C10 cell cultures or glands from individual animals. Binding data were analyzed using a nonlinear least-squares curve-fitting program. Ki, affinity in nanomolar concentration of drugs for inhibiting specific [3H]prazosin binding; nH, Hill coefficient. Affinity values from binding data that fit best to a two-site binding model are expressed as KiH (high-affinity binding site) and KiL (low-affinity binding site). % High, percentage of high-affinity binding sites; % Low, percentage of low-affinity binding sites.


Drug

Ki

nH

KiH

% High

KiL

% Low

n
SMG-C10 cells
   Prazosin 0.31 ± 0.1 —0.98 ± 0.2 4
   WB-4101a —0.63 ± 0.1 0.44 ± 0.1 35 ± 6 15 ± 4 65 ± 10 3
   5-methylurapidila —0.53 ± 0.1 1.9 ± 0.4 40 ± 8 100 ± 30 60 ± 10 8
   BMY-7378 81 ± 20 —0.83 ± 0.1 4
Submandibular gland
   Prazosin 0.78 ± 0.2 —0.78 ± 0.2 4
   WB-4101 0.76 ± 0.1 —0.83 ± 0.1 6
   5-methylurapidila —0.63 ± 0.1 3.2 ± 0.8 76 ± 10 170 ± 50 24 ± 4 8
   BMY-7378
110 ± 20
—0.80 ± 0.1




4
  • a Competition binding curve fit best to a two-site binding model (P < 0.05) using the F test