Investigating the Role of RhoA in the Development of Nerve Cell Electrical Excitability

Electrophysiology patch-clamping is a technique for measuring the electrical excitability of nerve cells. We are using this as a tool to study how new nerve cells develop. Stem cells have the ability to become other types of cells, including nerve cells. PC12 cells can be used to study this transition because, when cultured with Nerve Growth Factor (NGF), they become more nerve-like in at least three ways. (1) They stop dividing. (2) They grow long processes similar to axons and dendrites. (3) They become more electrically excitable. Previous research showed that if, prior to addition of NGF, PC12 cells are transfected with DNA which up-regulates the protein RhoA, the up-regulated RhoA prevents NGF from causing the first two changes. In our experiment, we used patch clamp techniques to study the third change. We found that up-regulating RhoA, perhaps surprisingly, did not prevent the increase in excitability caused by NGF, indicating that a different signaling molecule or pathway is involved with this change. In this talk, we will describe the techniques used to measure the cells electrical excitability, and we'll discuss possible future experiments to further study the signaling pathways in this important transition.