Hill equation parameter estimates for the in vivo effects of CPA analogs and R-PIA on heart rate in the rat
| α1-a | nH | pEC50 | |
|---|---|---|---|
| CPA | 205 ± 17.4 | 0.89 ± 0.29 | 8.45 ± 0.16 |
| (1600) | (0.06) | (0.08) | |
| 2′dCPA | 63 ± 12.2 | 1.31 ± 0.17 | 5.59 ± 0.05 |
| (930) | (0.62) | (0.09) | |
| 3′dCPA | 161 ± 14.4 | 1.09 ± 0.14 | 6.95 ± 0.09 |
| (1282) | (0.09) | (0.04) | |
| 5′dCPA | 273 ± 18.9 | 1.18 ± 0.04 | 7.30 ± 0.02 |
| (1920) | (0.89) | (0.11) | |
| 8MCPA | 130 ± 13.9 | 1.03 ± 0.14 | 6.39 ± 0.13 |
| (1018) | (0.64) | (0.05) | |
| 8ECPA | 123 ± 21.9 | 0.89 ± 0.12 | 5.97 ± 0.01 |
| (2938) | (0.16) | (0.00) | |
| 8PCPA | 111 ± 22.5 | 1.72 ± 0.41 | 6.40 ± 0.03 |
| (1011) | (0.90) | (0.08) | |
| 8BCPA | 54 ± 7.6 | 4.44 ± 0.57 | 6.15 ± 0.02 |
| (168) | (92.4) | (0.06) | |
| 8CPCPA | –1-b | –1-b | –1-b |
| R-PIA | 181 ± 21.5 | 2.26 ± 0.64 | 7.26 ± 0.04 |
| (2000) | (2.58) | (0.04) |
Parameter estimates (mean ± S.E, n = 6–7) for upper asymptote (α), Hill slope (nH) and midpoint location (pEC50) were obtained by nonlinear mixed-effect modeling as described under “Methods.” The variances (ω2) describing the interindividual parameter variation are shown in parentheses.