Effect of neuropeptideY on the T-type Ca^<2+> channel current

t型Ca^<2+>通道在调节神经元和非神经元可兴奋性细胞的兴奋性中起关键作用。神经肽y （neuropeptideY， NPY）是中枢和周围神经系统中表达最丰富的神经肽之一，其分布与t型Ca^<2+>通道的分布密切相关，提示其与t型Ca^<2+>通道存在功能相互作用。本研究的目的是探讨功能相互作用。在本研究的前半部分，我使用未分化的NG108-15细胞，证实了t型Ca^<2+>通道电流的表达。我发现使用Ba^<2+>作为电荷载体的全细胞膜片钳技术，低剂量的NPY显著增强了t型Ca^<2+>通道电流。NPY处理使I-V关系发生负向转变。使用NPY受体亚型选择性激动剂/拮抗剂进行的实验表明，Y_1和Y_2受体共同参与了电流的增强。与此一致，RT-PCR分析显示了Y_1和Y_2受体mrna的表达。在后半部分，为了研究ng108 -15细胞中所显示的功能相互作用，在脑准备中，我建立了海马切片培养系统，报道了表达蛋白质的海马切片。我用片膜片钳技术检测了CA1锥体神经元中表达的电压依赖性通道电流。需要进一步的工作来得出NPY对电压依赖性通道电流影响的结论。

T-type Ca^<2+> channel plays pivotal roles in regulating the excitability of the neurons and non-neuronal excitable cells. The neuropeptideY (NPY) is one of the most abundantly expressed neuropeptides in the central and peripheral nervous systems, and its distribution correlates well with that of T-type Ca^<2+> channel, suggesting a functional interaction with it. The aim of this study was to investigate the functional interaction. In the former half of this study, I used the undifferentiated NG108-15 cells, in which the expression of the T-type Ca^<2+> channel current was confirmed. I found that low doses of NPY significantly augmented the T-type Ca^<2+> channel current with whole cell patch-clamp technique using Ba^<2+> as the charge carrier. The NPY treatment shifted the I-V relationship negatively. Experiments using NPY receptor subtype-selective agonist/antagonists revealed that both Y_1 and Y_2 receptors additively involved in the augmentation of the current. Consistently, RT-PCR analysis showed the expressions of mRNAs for Y_1 and Y_2 receptors. In the later half, to investigate the functional interaction, which was shown in the NG 108-15 cells, in the brain preparation, I set up culture system of hippocampal slice, which was reported to express the proteins. I examined the voltage-dependent channel currents expressed in the CA1 pyramidal neurons with slice patch-clamp technique. Further work is needed to obtain the conclusion of the NPY's effect on the voltage-dependent channel currents.