Table 3.
Estimates of pentobarbital affinity at activation and block sites
| Kd1 (mm) | Kd2 (mm) | Kblock (mm) | Popen tail | |
|---|---|---|---|---|
| Independent model | ||||
| α1β3 | 22 ± 7 | 8 ± 3 | 0·7 ± 0·1 | 0·67 ± 0·12 |
| α1c1 | 231 ± 34 | 38 ± 5 | 0·7 ± 0·1 | 0·86 ± 0·02 |
| Coupled model | ||||
| α1β3 | 19 ± 5 | 8 ± 3 | 0·8 ± 0·1 | 0·66 ± 0·02 |
| α1c1 | 324 ± 39 | 40 ± 6 | 0·7 ± 0·1 | 0·85 ± 0·03 |
This table presents parameter estimates for the affinity of pentobarbital at the activation (Kd1=koff,1/kon,1 and Kd2=koff,2/kon,2) and block sites (Kblock=kb-/kb+) in α1β3 and αc1 receptors (see Fig. 12). Data are means ±s.e.m., calculated from the best fitting parameter values for data from 8 cells (α1c1) or 4 cells (α1β3). Data from each each cell comprised responses to 2–4 different concentrations of pentobarbital. The final column (Popen tail) gives the calculated maximal probability that channels are open at the peak of the largest tail currents for comparison to the values obtained from single-channel analyses.