Simulation of dendritic L-type ca channels' warm-up phenomenon in spinal motoneurons

In this study a computer-based model was developed to simulate the warm-up property of the low-voltage activated (LVA) L-type calcium channels. The LVA L-type calcium channel is one of two channels that mediate persistent inward currents in spinal alpha (a) motoneurons and plays an important role in integrating & modulating motor firing behaviors. This study was prompted by experimental observations that showed nonlinear and hysteretic behaviors of the LVA L-type calcium channel in a membrane patch, indicating that these nonlinear properties are part of the channel behavior. In this work, we introduce a new model for the LVA L-type calcium channel that incorporated the warm-up property. The new model has successfully reproduced experimental recordings from the membrane patch and from the whole cell. Our work provides a more accurate model of the LVA L-type calcium channel that could be used to reexamine the dendritic distribution of these channels on a-motoneurons.