Han Y, Jacoby R A, Wu S M
Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, 6565 Fannin, NC 205, Houston, TX 77030, USA.
Brain Res. 2000 Sep 1;875(1-2):175-86. doi: 10.1016/s0006-8993(00)02614-7.
Although isolated retinal cell preparations have been used widely to study retinal function in lower vertebrates, dissociated cells from primate retina have not been developed for routine physiological experiments. In this study, we demonstrated the feasibility of obtaining viable and identifiable dissociated cells from the primate retina. In addition, we characterized voltage-dependent membrane currents in each type of primate retinal cell with the whole-cell patch-clamp technique. Multiple types of ionic conductance with distinctive current profiles were recorded in various types of primate retinal neurons. Photoreceptors exhibited an inward I(H) activated by membrane hyperpolarization and an outward current activated at depolarized potentials. Two types of potassium currents (transient potassium current, I(K(A)), and delayed rectifier potassium current, I(K(V))) were recorded from bipolar cells. I(K(A)) dominated the current response in putative midget bipolar cells, and I(K(V)) was mainly associated with putative rod bipolar cells. L-type calcium currents (I(Ca)) were observed in primate bipolar cells with axon terminals, but not in axotomized bipolar cells. Large voltage-dependent sodium currents (I(Na)) were only recorded from ganglion cells. Muller cells exhibited I(K(V)) and large potassium inward rectifier current (I(K(IR))), and occasionally a small I(Na). Neurons with electrophysiological signatures of amacrine cells and horizontal cells were also studied even though their morphological features were lost during cell dissociation. By using both morphological and physiological criteria outlined in this report, it is possible to use the dissociated retinal cell preparation as an in vitro system for physiological, biochemical and pharmacological studies of the primate visual system.
尽管分离的视网膜细胞制剂已被广泛用于研究低等脊椎动物的视网膜功能，但灵长类动物视网膜的解离细胞尚未用于常规生理实验。在本研究中，我们证明了从灵长类动物视网膜获得存活且可识别的解离细胞的可行性。此外，我们用全细胞膜片钳技术对每种灵长类动物视网膜细胞的电压依赖性膜电流进行了表征。在各种灵长类动物视网膜神经元中记录到了具有独特电流特征的多种离子电导。光感受器表现出由膜超极化激活的内向I(H)电流和在去极化电位时激活的外向电流。从双极细胞记录到了两种类型的钾电流（瞬时钾电流，I(K(A))，和延迟整流钾电流，I(K(V))）。I(K(A))在假定的侏儒双极细胞的电流反应中占主导地位，而I(K(V))主要与假定的视杆双极细胞相关。在有轴突终末的灵长类双极细胞中观察到了L型钙电流（I(Ca)），但在轴突切断的双极细胞中未观察到。仅从神经节细胞记录到了大的电压依赖性钠电流（I(Na)）。米勒细胞表现出I(K(V))和大的钾内向整流电流（I(K(IR))），偶尔还有小的I(Na)。即使在细胞解离过程中失去了形态特征，也对具有无长突细胞和水平细胞电生理特征的神经元进行了研究。通过使用本报告中概述的形态学和生理学标准，有可能将解离的视网膜细胞制剂用作灵长类视觉系统生理、生化和药理学研究的体外系统。
