TABLE 1

Binding properties of HA-tagged α1-AR subtypes expressed in HEK293 cells

α1-AR subtypes with N-terminal HA tags were stably expressed in HEK293 cells, membranes were harvested, and saturation of specific 125IBE binding measured as described under Materials and Methods. Bmax and KD values were calculated by nonlinear regression of saturation curves, and pKI values for inhibition of binding by NE, prazosin, (+)-niguldipine, and BMY7378 were determined. Values are presented as mean ± S.E.M. of three experiments performed in duplicate.

Subtypes expressed pKI
Bmax KD NE Prazosin (+)-Niguldipine BMY7378
fmol/mg pM
HA-α1A 1364 ± 193 45 ± 12 4.9 ± 0.12 9.0 ± 0.15 9.3 ± 0.04 6.0 ± 0.08
HA-α1B 16165 ± 1050 38 ± 13 5.0 ± 0.09 9.3 ± 0.09 6.9 ± 0.04 6.1 ± 0.09
HA-α1D 331 ± 10 59 ± 14 5.5 ± 0.14 9.4 ± 0.27 6.9 ± 0.35 8.3 ± 0.19