Giovanelli A, Fucile S, Mead A, Mattei E, Eusebi F, Sears M
Dipartimento Medicina Sperimentale Universitá dell' Aquila, Roma, Italy.
Biochem Biophys Res Commun. 1996 Mar 18;220(2):472-7. doi: 10.1006/bbrc.1996.0423.
Under confocal microscopy, calcium imaging of the isolated secretory ciliary epithelium, especially the inner layer, non-pigmented epithelium (NPE), revealed spontaneous calcium oscillations in multiple patterns. Oscillations induced by stimulation of the muscarinic receptor have an onset that coincides with synthesis and release of InsP3. Caffeine (5 mM) induced a calcium transient and blocked spontaneous and (0.1 mM) muscarine induced oscillations. Thapsigargin (1 microM) prevented a muscarinic response. Muscarine and caffeine induced transients have significantly greater amplitude in NPE than in PE (outer layer, pigmented epithelium). Calcium transients and frequencies of spontaneous oscillations are greater in NPE than PE. In NPE muscarine induced oscillations are observed with higher frequencies than the spontaneous ones: gamma-0.24 +/- 0.05Hz (8) versus 0.08 +/- 0.01Hz (18). These repetitive responses, spontaneous and receptor coupled, reflect intracellular coding of information. A calcium signal may contribute to the regulation of aqueous humor formation.
在共聚焦显微镜下，对分离出的分泌性睫状上皮，尤其是内层无色素上皮（NPE）进行钙成像，发现其存在多种模式的自发钙振荡。毒蕈碱受体刺激诱导的振荡起始与肌醇三磷酸（InsP3）的合成和释放同时发生。咖啡因（5 mM）诱导钙瞬变，并阻断自发振荡以及（0.1 mM）毒蕈碱诱导的振荡。毒胡萝卜素（1 microM）可阻止毒蕈碱反应。毒蕈碱和咖啡因诱导的瞬变在NPE中的幅度明显大于色素上皮（PE，外层）。NPE中的钙瞬变和自发振荡频率高于PE。在NPE中，观察到毒蕈碱诱导的振荡频率高于自发振荡频率：γ-0.24±0.05Hz（8次）对0.08±0.01Hz（18次）。这些自发的和受体偶联的重复反应反映了细胞内的信息编码。钙信号可能有助于调节房水生成。
