Furukawa M, Enomoto K, Kato H, Ishida T, Maeno T
Department of Radiology, Shimane Medical University, Japan.
Cell Biochem Funct. 1992 Dec;10(4):225-32. doi: 10.1002/cbf.290100403.
Effects of hyperthermia on the intracellular calcium concentration (Cai) of an established mouse breast cancer cell line, MMT060562, were studied using fura-2 fluorescence microscopy and the whole-cell clamp technique. A sudden change of temperature from 37 to 45 degrees C induced a transient increase in the fluorescence ratio permeability of the cell membrane and inward current. Deletion of extracellular calcium abolished the fluorescence ratio response to the rise in temperature. Cai of some cells increased after hyperthermia treatment at 44-48 degrees C for 20 min, but the average increase of Cai was negligible. After hyperthermia treatment, spontaneous oscillation of Cai, chemical responses to ATP and bradykinin and the mechanically-induced spreading response diminished. However, the mechanically induced increase of Cai within the stimulated cell remained even after hyperthermia treatment. Suppression of the ATP-induced Cai response recovered to about half the original level within 12 h. Blockage of protein synthesis with cycloheximide (100 microM) had no effect on the recovery. The D-myo-inositol 1,4,5-triphosphate (IP3)-dependent increase of Cai remained intact even after hyperthermia treatment. It is concluded that hyperthermia treatment increases both the permeability of the cell membrane and Cai, but decreases the sensitivity of cells to ATP and bradykinin, presumably due to modification of the signal transduction mechanism.
采用fura - 2荧光显微镜和全细胞膜片钳技术，研究了热疗对已建立的小鼠乳腺癌细胞系MMT060562细胞内钙浓度（Cai）的影响。温度从37℃突然升至45℃会导致细胞膜荧光比率通透性和内向电流短暂增加。去除细胞外钙可消除温度升高引起的荧光比率反应。在44 - 48℃热疗20分钟后，部分细胞的Cai升高，但Cai的平均升高可忽略不计。热疗后，Cai的自发振荡、对ATP和缓激肽的化学反应以及机械诱导的铺展反应减弱。然而，即使在热疗后，刺激细胞内机械诱导的Cai增加仍然存在。ATP诱导的Cai反应抑制在12小时内恢复到约原始水平的一半。用环己酰亚胺（100 microM）阻断蛋白质合成对恢复没有影响。即使在热疗后，依赖D - 肌醇1,4,5 - 三磷酸（IP3）的Cai增加仍保持完整。结论是，热疗增加了细胞膜通透性和Cai，但降低了细胞对ATP和缓激肽的敏感性，推测是由于信号转导机制的改变。
