Effect of pinacidil (5.0 μM) on the contractile response to oxotremorine-M in smooth muscle from wild-type and M2muscarinic receptor KO mice
| Ileum | Trachea | Urinary Bladder | |
|---|---|---|---|
| Wild Type (n = 4) | |||
| E max(% control)4-a | 125 ± 11 | 80 ± 4.14-b | 107 ± 6.4 |
| EC50 Shift (fold4-c | 3.24-b | 4.14-b | 1.7 |
| (0.50 ± 0.059) | (0.62 ± 0.084) | (0.22 ± 0.070) | |
| M2 Receptor KO (n = 4) | |||
| E max (% control)4-b | 137 ± 3.84-b | 87 ± 4.4 | 111 ± 9.5 |
| EC50 Shift (fold)4-c | 2.24-a 4-b | 3.94-b | 1.5 |
| (0.35 ± 0.055) | (0.59 ± 0.070) | (0.19 ± 0.070) |
Mean values ± S.E.M. from four wild-type and four M2receptor knockout mice are shown.
↵4-a Denotes theEmax value of oxotremorine-M measured in the presence of pinacidil divided by that measured in its absence, expressed as a percentage.
↵4-b A significant effect of pinacicil relative to control. The probability values for these differences are as follows. Wild-type mice, effects of pinacidil on Emax in trachea, P = 0.016; EC50 shift in ileum and trachea, P = 0.0035 and 0.0052. M2 muscarinic receptor knockout mice, effects of pinacidil on Emax in ileum, P = 0.0022; EC50 shift in ileum and trachea, P = 0.0079 and 0.0035.
↵4-c Denotes the EC50value of oxotremorine-M measured in the presence of pinacidil divided by that measured in its absence. The values in parentheses beneath each estimate represent the mean log shift values ± S.E.M.