Mendelowitz D, Kunze D L
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030.
Neurosci Lett. 1991 Nov 11;132(2):217-21. doi: 10.1016/0304-3940(91)90305-d.
This study describes a preparation that will enable us to study, using voltage clamp techniques, ionic currents from dissociated cardiovascular neurons that have retained their anatomical and functional identity of the intact animal. To identify dispersed preganglionic cardiac motoneurons various fluorescent dyes (rhodamine, fluorogold, microspheres, bizbenzimide and dextrans) were examined to determine which can be absorbed by preganglionic cardiac motorneuron nerve terminals (without surgical penetration of cardiac tissue), transported retrogradely to their soma in the medulla and retained during dissociation of the neurons. Rhodamine fulfilled these criteria. Dissociated preganglionic cardiac motorneurons had resting membrane potentials of -52.4 +/- 3 mV and input resistances of 236 +/- 71 M omega (mean +/- S.E.M., n = 10). Depolarizing voltage steps to -50 mV or above evoked a tetrodotoxin (TTX) sensitive inward sodium current followed by a biphasic outward current.
本研究描述了一种制备方法，该方法将使我们能够利用电压钳技术研究来自已解离的心血管神经元的离子电流，这些神经元保留了完整动物的解剖学和功能特性。为了识别分散的节前心脏运动神经元，研究人员检查了各种荧光染料（罗丹明、荧光金、微球、双苯甲酰亚胺和葡聚糖），以确定哪些染料可以被节前心脏运动神经元的神经末梢吸收（无需手术穿透心脏组织），逆行运输到它们在延髓的胞体，并在神经元解离过程中保留下来。罗丹明符合这些标准。解离后的节前心脏运动神经元的静息膜电位为-52.4±3mV，输入电阻为236±71MΩ（平均值±标准误，n = 10）。去极化电压阶跃至-50mV或更高会诱发一种对河豚毒素（TTX）敏感的内向钠电流，随后是双相外向电流。
