POSTER link: IMI Stakeholder Forum 2019
It has been demonstrated that sensory neurons possess electrical activity in response to capsaicin already after few hours in vitro; however, in the case of purified neurons, this activity is largely reduced after 1 day in vitro. This cannot be explained by a lack in the capsaicin receptor TRPV1, whose presence has been proved by calcium-imaging experiment.
Perforated patch-clamp experiments showed no major differences in membrane depolarization between purified and non-purified neurons. However, although perforated patch-clamp is considered less invasive than the traditional patch-clamp, the small pores generated from amphotericin may still alter the intracellular concentrations of ions important for neuronal excitability.
The ability of purified neurons to be activated by capsaicin during the first 24 hours only after plating suggests their dependence on non-neuronal cells for the expression of proteins which may be required to preserve their excitability. All these data combined lead to the hypothesis that non-neuronal cells, such as Schwann cells and satellite glial cells, play an active role in establishing the excitability of sensory neurons under physiological and pathological conditions, such as chronic pain. Future studies, which include conditioned medium experiments and the use of permeable membrane for cell culture, will be addressed in order to identify proteins that are dysregulated in purified sensory neurons, and their relationship with non-neuronal cells.