TABLE 2

Analysis of modulation of the ρ1 receptor by steroids

The table summarizes the results of fitting the steroid conc.-Popen response data from ρ1 wild-type and I307Q mutant receptors to eq. 2. The experiments were conducted in the presence of GABA, and L was calculated as (1−Popen,GABA)/Popen,GABA. The number of binding sites for steroids was constrained to five, and the maximal Popen for GABA was assumed to be 0.999.

ReceptorSteroidKC (μM)c
ρ1 wild-type3α5βP2.85 ± 0.621.25 ± 0.02
3α5βPS51.1 ± 25.32.34 ± 0.89
β-Estradiol16.4 ± 4.81.47 ± 0.07
5αTHDOC38.2 ± 28.60.58 ± 0.07
ρ1(I307Q)3α5βP20.5 ± 15.10.55 ± 0.05
5αTHDOC28.6 ± 26.10.49 ± 0.08