Goligorsky M S, Loftus D J, Hruska K A
Am J Physiol. 1986 Nov;251(5 Pt 2):F938-44. doi: 10.1152/ajprenal.1986.251.5.F938.
The development of high quantal yield Ca2+-sensitive fluorescent indicators has made microspectrofluorometric monitoring of cytoplasmic calcium feasible. The detailed technique to monitor cytoplasmic calcium concentration in individual proximal tubular cells grown on glass cover slips is described. Manipulations of cytoplasmic calcium concentration by means of a Ca2+ ionophore or Ca2+-free medium resulted in corresponding changes of fura-2 fluorescence. Parathyroid hormone elicited a fivefold increase in cytoplasmic calcium concentration, with the subsequent complete recovery of this parameter in 3 min. This effect of parathyroid hormone was abolished by perfusion of the cells with Ca2+-free medium. Repeated pulses of parathyroid hormone spaced at an interval of 20 min, caused refractoriness of adenosine 3',5'-cyclic monophosphate response, whereas cytoplasmic calcium transients remained unaltered. When the frequency of the sequential pulses with parathyroid hormone was increased (5 min intervals), the amplitude of calcium transients was diminished, and the recovery of basal level of cytoplasmic calcium was incomplete and protracted. These observations may have application to disordered renal cell calcium metabolism in hyperparathyroid states.
高量子产率的钙离子敏感荧光指示剂的发展使得对细胞质钙进行显微分光荧光监测成为可能。本文描述了在玻璃盖玻片上生长的单个近端肾小管细胞中监测细胞质钙浓度的详细技术。通过钙离子载体或无钙培养基对细胞质钙浓度进行操作会导致fura-2荧光发生相应变化。甲状旁腺激素使细胞质钙浓度增加了五倍，随后在3分钟内该参数完全恢复。用无钙培养基灌注细胞可消除甲状旁腺激素的这种作用。以20分钟的间隔重复给予甲状旁腺激素脉冲，会导致腺苷3',5'-环磷酸单酯反应出现不应性，而细胞质钙瞬变保持不变。当甲状旁腺激素连续脉冲的频率增加（间隔5分钟）时，钙瞬变的幅度减小，细胞质钙基础水平的恢复不完全且延迟。这些观察结果可能适用于甲状旁腺功能亢进状态下紊乱的肾细胞钙代谢。
