Fig. 9. 5-HT_1Hel receptor immunoreactivity in identified Helisoma ciliary cells. Nomarski differential interference contrast (DIC) images (left panels) and corresponding fluorescence micrographs (right panels) of tissue explants containing identified ciliary cells that were processed for 5-HT_1Hel immunoreactivity. Arrows indicate the apical surface of the ciliary cells. (A) Immunopositive pedal ciliary cell. (B) Immunoreactivity in multiple dorsolateral ciliary cells. (C) Immunoreactivity restricted to the non-ciliary epithelial cells (asterisks) surrounding an unstained single ciliary cell. (D) A control explant containing pedal ciliary cells was exposed to preimmune serum instead of primary antibody. Scale bars, 10 µm.