DeFazio T, Walsh J P
Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles 90089-0191, USA.
Neurosci Lett. 1996 Apr 12;208(1):29-32. doi: 10.1016/0304-3940(96)12543-x.
Calcium channels play an important role in generating the complex electrophysiology of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNc). To directly study these calcium currents in dendritically intact neurons, two issues needed to be addressed: the identity of the neuron (DAergic versus non-DAergic) and control of putative dendritic calcium conductances. A measure of the anomalous rectifier (Ih) was used to identify DAergic neurons. Both groups of neurons produced large (approximately 1 nA), sustained inward currents that persisted as 'plateau currents' for hundreds of milliseconds after the termination of the depolarizing voltage clamp step. We conclude that intact DAergic neurons can be identified under conditions optimal for recording calcium currents (i.e. Cs+ internal solution), but powerful dendritic currents limit rigorous biophysical analysis.
钙通道在黑质致密部（SNc）多巴胺能（DAergic）神经元复杂的电生理活动产生过程中发挥着重要作用。为了直接研究树突完整的神经元中的这些钙电流，需要解决两个问题：神经元的身份（多巴胺能与非多巴胺能）以及对假定的树突钙电导的控制。使用反常整流（Ih）的测量方法来识别多巴胺能神经元。两组神经元均产生了大的（约1 nA）持续性内向电流，在去极化电压钳制步骤终止后，该电流作为“平台电流”持续数百毫秒。我们得出结论，在记录钙电流的最佳条件下（即Cs +内部溶液）可以识别完整的多巴胺能神经元，但强大的树突电流限制了严格的生物物理分析。
