Finally, in the spinal cord, we identified 22 cell types, again split into inhibitory (GABAergic or glycinergic) and glutamatergic (VGLUT2) in good agreement with an independent experiment focused on the dorsal horn (Häring et al., 2018) (Table S2). In addition, here we identified central canal neurons (SCINH11), known as cerebrospinal fluid-contacting neurons, which expressed transcription factors Gata2 and Gata3 (Figure S7) (Petracca et al., 2016). They also specifically expressed polycystin-like genes (Pkd1l2 and Pkd2l1), which encode a mechanosensory protein complex that detects fluid flow, and Espn, which encodes an actin bundling protein with a major role mediating sensory transduction in mechanosensory cells. Thus, central canal neurons are likely specialized cells that monitor cerebrospinal fluid flow.
