Table 4.
Thermodynamics of antagonist dissociation
| 25°C | 37°C | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Antagonist | n | l−1 (s−1) | n | l−1 (s−1) | Q10 | Ea‡ (kJ mol−1) | ΔH‡ (kJ mol−1) | ΔS‡ (kJ mol−1 K−1) | ΔG‡25°C (kJ mol−1) | ΔG‡37°C (kJ mol−1) |
| (+)-Tubocurarine | 8 | 6 ± 1 | 7 | 31 ± 8 | 4.0 ± 0.4 | 106 ± 8 | 104 ± 8 | 0.25 ± 0.3 | 29 ± 0.6 | 26 ± 0.6 |
| Pancuronium | 12 | 2 ± 1 | 6 | 13 ± 4 | 4.5 ± 0.6 | 116 ± 10 | 113 ± 10 | 0.27 ± 0.4 | 31 ± 0.7 | 28 ± 0.8 |
| Cisatracurium | 15 | 34 ± 6 | 5 | 139 ± 16 | 3.2 ± 0.2 | 90 ± 6 | 88 ± 6 | 0.21 ± 0.3 | 24 ± 0.5 | 22 ± 0.3 |
n, number of experiments; l−1, dissociation rate constant; other symbols as in Table 3. Data for (+)-tubocurarine, pancuronium and cisatracurium at 25°C were previously published (Demazumder & Dilger, 2001; Wenningmann & Dilger, 2001). l−1 values were significantly different among the antagonists at both temperatures (P < 0.0001). Q10, Ea‡ and ΔH‡ were the same for (+)-tubocurarine and pancuronium, but these values were significantly different from those for cisatracurium (P < 0.01); ΔG‡ values at 25°C were significantly different from those at 37°C for all antagonists (P < 0.0001).