Ishii T, Shimo Y
Naunyn Schmiedebergs Arch Pharmacol. 1986 Mar;332(3):219-23. doi: 10.1007/BF00504857.
Isolated tracheal strip-chain preparation of the guinea-pig was used to study the effect of temperature on carbachol-induced contraction. The preparation was suspended in the organ bath containing Krebs bicarbonate solution for isometric tension recording. A decrease of bath temperature from 37 degrees C to 20 degrees C (cooling) caused a transient increase in tension and thereafter inhibited the contractile response of the trachea caused by carbachol (30 nmol/l-3 mumol/l). Isosmotic potassium chloride (KCl, 64.7 mmol/l)-induced contraction or calcium chloride (CaCl2, 0.1--3 mmol/l)-induced contraction in K+-depolarized muscle was markedly inhibited by cooling. Verapamil in concentrations of 1 mumol/l or greater, which markedly depressed the CaCl2-induced contraction, caused partial depression of the contractile response to carbachol. On the other hand, carbachol-induced contraction of the trachea which was incubated with K+-rich, verapamil (3 mumol/l) containing Krebs solution and with Ca2+-free, EGTA (0.4 mmol/l) containing Krebs solution were both augmented at 20 degrees C. From these observations, it is concluded that decreased responsiveness of the guinea-pig airway smooth muscle to carbachol with lowered temperature may be due to an inhibition of Ca2+ influx through voltage-dependent Ca2+ channels which involves part of the contraction.
采用豚鼠离体气管条链制备物研究温度对卡巴胆碱诱导收缩的影响。将制备物悬挂于含有 Krebs 碳酸氢盐溶液的器官浴中进行等长张力记录。浴温从 37℃降至 20℃(冷却)会导致张力短暂升高,随后抑制卡巴胆碱(30 nmol/l - 3 μmol/l)引起的气管收缩反应。冷却可显著抑制等渗氯化钾(KCl,64.7 mmol/l)诱导的收缩或钾离子去极化肌肉中氯化钙(CaCl2,0.1 - 3 mmol/l)诱导的收缩。浓度为 1 μmol/l 或更高的维拉帕米可显著抑制氯化钙诱导的收缩,导致对卡巴胆碱收缩反应的部分抑制。另一方面,在含有高钾、维拉帕米(3 μmol/l)的 Krebs 溶液以及不含钙、含乙二醇双四乙酸(EGTA,0.4 mmol/l)的 Krebs 溶液中孵育的气管,其卡巴胆碱诱导的收缩在 20℃时均增强。从这些观察结果得出结论,豚鼠气道平滑肌对卡巴胆碱的反应性随温度降低而降低可能是由于抑制了通过电压依赖性钙通道的钙离子内流,而这涉及部分收缩过程。