A central issue in developmental neurobiology concerns what factors are involved in the differentiation of ion channels in developing neurons. This issue will be studied in migrating neurons that form the enteric nervous system in the moth, Manduca. This system is uniquely suited for such studies since the developmental fates of these neurons are well characterized, there are only 300 neurons in this system and these are easily accessible for electrophysiological recording and experimental manipulation in the embryo. In addition, these neurons can be removed from the embryo and studied in culture. Intracellular and patch clamp recordings will be performed on identified neurons during and after their migration in situ and in culture to study the expression and development of voltage dependent potassium, calcium dependent potassium, sodium and calcium currents. These studies will lead in the future to molecular and genetic analyses of channel gene expression.