MOLECULAR ANALYSIS OF IH CURRENT IN THE NERVOUS SYSTEM

称为I/h的超极化激活阳离子通道是一种缓慢的内向电流，对Na+和K+都具有渗透性。它已被发现在不同的细胞类型在不同的物种，并有助于显着的静息膜电位，神经元放电模式，过度超极化的限制。虽然这股电流的重要生理功能已被充分证明，但仍有许多问题没有得到解答。这些通道的分子组分最近已被鉴定，并且属于称为HCN基因家族的密切相关的基因家族。该建议的主要重点是了解已识别的HCN通道、可能的额外亚基和天然电流之间的关系。通过RNA酶保护测定和原位杂交确定的HCN通道的表达模式将首先与天然电流的表达进行比较。同源/异源HCN通道的生物物理和药理学特性将使用异源表达系统进行系统研究，并与天然电流进行比较。不同HCN通道之间的异聚化也将使用免疫共沉淀进行研究。天然通道需要辅助亚基的假设将进一步探讨。这项研究是必要的，以进一步探讨机制产生的通道多样性，并确定该通道的生理和病理功能的贡献。

The hyperpolarization-activated cation channel called I/h is a slow inward current and permeable to both Na+ and K+. It has been found in a diverse group of cell types in various species and contributes significantly to the resting membrane potential, neuronal firing patterns, and the limitation of excessive hyperpolarization. Although well documented and important physiological functions are known for this current, many unanswered questions remain. The molecular components of these channels have been identified recently and belong to a closely related gene family called the HCN gene family. The major focus of this proposal is to understand the relationships between the identified HCN channels, possible additional subunits, and the native currents. The expression patterns of HCN channels determined by RNase protection assays and in situ hybridization will first be compared to the expression of the native current. The biophysical and pharmacological properties of homo/heteromeric HCN channels will be studied systematically using heterologous expression systems and compared to that of the native currents. The heteromerization among different HCN channels will also be investigated using coimmunopreciptation. The hypothesis that native channels requires an auxiliary subunit will be further explored. This study is essential to further investigate the mechanism generating channel diversity and to determine the contribution of this channel to physiological and pathological function.