Subpopulations of nociceptors express kainate receptors. Acutely dissociated DRG neurons were plated on glass coverslips with grids. Each grid has unique lettering, which helped us to relocate the same field of view after Ca²⁺imaging followed by immunostaining with various markers. A, B, The area in the rectangle in Ais zoomed in B. A field is imaged, and kainate is applied to look for kainate receptor-mediated responses.Traces in B show that only thetop two cells had Ca²⁺ responses to 100 μm kainate. C, D, The same field of neurons in B costained with LA4 and VR1 is shown. The top two cells show VR1 expression (D), whereas the bottom two cells show LA4 expression (C).