Table 3. Comparison of inotropic response to β-adrenergic stimulation of left ventricle papillary muscles of healthy or diabetic rats, pretreated or not with atorvastatin.
| Isoproterenol | Healthy untreated (n = 8) | Healthy statin (n = 8) | Diabetic untreated rats (n = 8) | Diabetic statin (n = 8) | ||||
|---|---|---|---|---|---|---|---|---|
| Vmax | AF/s | Vmax | AF/s | Vmax | AF/s | Vmax | AF/s | |
| maxEff (% baseline value) | 181±11* | 184±22* | 194±30* | 177±22* | 128±7* | 112±15*† | 174±27*‡ | 158±34*†‡ |
| C50 (μM) | 0.16±0.15 | 0.20±0.15 | 0.91±1.14 | 0.81±1.15 | 0.07±0.06 | 0.07±0.05 | 0.09±0.08 | 0.28±0.34 |
Data are mean ± SD
*: p<0.05 versus untreated healthy group
†: p<0.05 between statin and untreated rats in each group healthy or diabetic rats
‡: p<0.05 between healthy statin rats and diabetic statin rats. Vmax = maximal unloading isotonic shortening velocity; AF/s = active force normalized per cross-sectional area during isometric contraction; maxEff = maximal effect of isoproterenol on AF as percentage of baseline value; C50 = concentration of isoproterenol producing 50% of maxEff.