Mori K, Hashimoto H, Hasegawa H, Nakashima M
Eur J Pharmacol. 1979 Apr 15;55(2):189-97. doi: 10.1016/0014-2999(79)90391-1.
The influence of the bath temperature on the responsiveness to sympathomimetic amines was studied with isolated guinea pig and rat atria. In electrically driven guinea pig left atria, the dose-response curve for the positive inotropic effect of isoproterenol (ISO) was shifted to the left by lowering the temperature from 36 to 24 degrees C. The positive inotropic effect of phenylephrine (PHE) in lower concentrations was attenuated by lowering the temperature. Phentolamine markedly inhibited the PHE response at 36 and 32 degrees C, whereas it produced no inhibition at 24 degrees C. Similar changes were observed with rat left atria. In guinea pig left atria, propranolol inhibited the response to PHE more effectively at 24 degrees C than 32 degrees C. With guinea pig and rat atria the dose--response curve for the positive inotropic effect of PHE in the presence of phentolamine was shifted to the left by lowering the temperature. The results suggest that lowering the temperature of the bath solution diminished the positive inotropic effect of PHE mediated by alpha-adrenoceptors and potentiated that mediated by beta-adrenoceptors.
利用豚鼠和大鼠离体心房研究了浴温对拟交感胺反应性的影响。在电驱动的豚鼠左心房中，将温度从36℃降至24℃可使异丙肾上腺素（ISO）正性肌力作用的剂量反应曲线左移。降低温度可减弱低浓度去氧肾上腺素（PHE）的正性肌力作用。酚妥拉明在36℃和32℃时显著抑制PHE反应，但在24℃时无抑制作用。在大鼠左心房也观察到类似变化。在豚鼠左心房中，普萘洛尔在24℃时比在32℃时更有效地抑制对PHE的反应。对于豚鼠和大鼠心房，降低温度可使酚妥拉明存在时PHE正性肌力作用的剂量反应曲线左移。结果表明，降低浴液温度可减弱由α-肾上腺素能受体介导的PHE正性肌力作用，并增强由β-肾上腺素能受体介导的该作用。
