NGF-induced reduction of an outward-rectifying TRPM7-like current in rat CA1 hippocampal neurons

Transient receptor potential melastatin 7 (TRPM7) channels are widely expressed in the nervous system; however, their function and regulation are largely unknown. This study aimed to explore whether the current mediated by TRPM7-like channels in rat CA1 hippocampal neurons could be modulated by nerve growth factor (NGF). Using whole-cell patch clamp techniques, we identified an outward-rectifying TRPM7-like current in hippocampal neurons freshly isolated from postnatal (10-day-old) rats. The outward component of this current was reversibly reduced by NGF in dose- and time-dependent manners, and this effect was substantially blocked by K252a, an inhibitor of TrkA. In addition, NGF-induced reduction of the TRPM7-like current was abolished by U73122, a phopholipase C inhibitor. In light of the abundance of NGF in hippocampus that express both TrkA and TRPM7, these results suggest that the function of TRPM7-like channels in hippocampal neurons may be regulated by NGF.