Himpens B, Stalmans P, Gomez P, Malfait M, Vereecke J
Laboratory of Physiology, KULeuven, B-3000 Leuven, Belgium.
FASEB J. 1999;13 Suppl:S63-8. doi: 10.1096/fasebj.13.9001.s63.
The intercellular communication (IC) was investigated between cultured rat retinal pigment epithelial (RPE) cells isolated from Long-Evans (LE) or dystrophic Royal College of Surgeons (RCS) rats and grown in solutions containing normal and high glucose concentrations, or after modulation of protein kinase C (PKC). This was performed by studying the conduction of the free Ca2+-concentration ([Ca2+]i) wave elicited by mechanical stimulation and by analyzing the fluorescence recovery after photobleaching (FRAP). Mechanical stimulation of LE-RPE cells triggers Ca2+ influx, mediated by stretch-sensitive cation channels followed by intracellular Ca2+ release. A regenerative [Ca2+]i wave was found with a lower propagation rate in RCS-RPE cells. This rate could be increased by PKC down-regulation. Mechanical stimulation caused a [Ca2+]i increase in the mechanically stimulated (MS) cell followed after a delay by a [Ca2+]i rise in the adjacent cell layers. The intercellular [Ca2+]i wave propagation could be blocked by gap junction blockers such as halothane or PKC activation. An inhibition of the [Ca2+]i-wave propagation similar to that induced by halothane could be observed in cells grown in solutions containing 14 mM or higher concentrations of glucose. PKC down-regulated cells grown in glucose-rich medium did not develop this inhibitory effect on gap junction communication (GJC). FRAP experiments confirmed that the observed changes were consistent with a PKC-mediated inhibitory effect of high glucose concentrations on GJC.
研究了从长 Evans（LE）大鼠或营养不良的皇家外科学院（RCS）大鼠分离的培养大鼠视网膜色素上皮（RPE）细胞之间的细胞间通讯（IC），这些细胞在含有正常和高葡萄糖浓度的溶液中生长，或在蛋白激酶 C（PKC）调节后进行研究。这是通过研究机械刺激引发的游离 Ca2+浓度（[Ca2+]i）波的传导以及分析光漂白后的荧光恢复（FRAP）来进行的。对 LE-RPE 细胞的机械刺激触发 Ca2+内流，由拉伸敏感阳离子通道介导，随后是细胞内 Ca2+释放。在 RCS-RPE 细胞中发现了再生性[Ca2+]i 波，其传播速率较低。PKC 下调可提高该速率。机械刺激导致机械刺激（MS）细胞中的[Ca2+]i 增加，随后相邻细胞层中的[Ca2+]i 延迟升高。细胞间[Ca2+]i 波的传播可被间隙连接阻滞剂（如氟烷）或 PKC 激活阻断。在含有 14 mM 或更高浓度葡萄糖的溶液中生长的细胞中，可观察到类似于氟烷诱导的[Ca2+]i 波传播抑制。在富含葡萄糖的培养基中生长的 PKC 下调细胞对间隙连接通讯（GJC）没有产生这种抑制作用。FRAP 实验证实，观察到的变化与高葡萄糖浓度对 GJC 的 PKC 介导的抑制作用一致。
