Choroid plexus (CP) epithelia main function consists in producing and regulating cerebrospinal fluid (CSF). Such regulation is achieved through transepithelial solute transport via plasma membrane ion channels and transporters. Interestingly, steroids and specially progesterone has been shown to exert potent neuroprotective action. Since fluid secretion in CP is under control of ion channels and transporters, we aim to explore whether progesterone can modulate Transient Receptor Potential channel activity directly in an unconventional manner meaning a rapid non-genomic way. The outcome of this research may be of interest for treatment of CSF malfunctions such as traumatic brain injury.