Cellular localization of epithelial Ca2+ channel TRPV6 along the male excurrent duct. (A) RT-PCR detection of mRNA for TRPV6 in the rat efferent duct and the different regions of epididymis, including the initial segment and caput, corpus, and cauda epididymides. No TRPV5 mRNA was detected in these tissues (except in the kidney, which was used as a positive control). RT+, PCR products with RNA sample templates; RT−, no RNA template control. GAPDH, glyceraldehyde 3-phosphate dehydrogenase. (B–G) Immunoperoxidase detection of TRPV6 protein (brown) in the rat efferent duct (B), initial segment (C), caput (D), corpus (E), and cauda epididymides (F). Negative control for immunohistochemistry without primary antibody showed no brown immunoperoxidase product (G). Arrows indicate the vesicle-like structures in the luminal content; the asterisk in C indicates a halo cell. L, lumen; I, interstitial tissue. Bar, 20 µm. (H) Western blot detection of TRPV6 protein (∼83 kD, arrow) using the same antibody in total homogenates as indicated. MW, molecular weight. (I and J) Specificity of the TRPV6 antibody was confirmed by the absence of immunoprecipitation after immunopeptide preabsorption.
