HAMSTER PULMONARY ENDOCRINE-CELLS WITH NEURAL CELL-ADHESION MOLECULE (NCAM) IMMUNOSTAINING

Pulmonary endocrine cells of Syrian golden hamster were stained for ne ural cell adhesion molecule (NCAM) with indirect fluorescent immunosta ining and observed with a confocal laser scanning microscope equipped with an argon laser. Sections 100 mu m thick of hamster lung fixed wit h phosphate-buffered 4% paraformaldehyde were prepared. The sections w ere incubated with rat monoclonal antibody against NCAM, followed by f luorescence-labeled antibody against rat immunoglobulin. Some were dou bly immunostained for NCAM and one of the following endocrine markers: neuron-specific enolase, calcitonin gene-related peptide and serotoni n. Expression of NCAM in the hamster airway epithelium was seen in cel l nests resembling neuroepithelial bodies (NEBs). NCAM. immunostaining was positive at the lateral cell borders between the cells composing the nest, but negative at the border with the adjacent, presumably non -endocrine cells. Double immunostaining confirmed that the grouped cel ls with NCAM immunoreactivity were of an endocrine nature, but that si ngle endocrine cells did not show NCAM immunoreactivity. An electron m icroscopic study with NCAM immunostaining confirmed the light microsco pic study. These suggest that NCAM expression could be important for t he morphogenesis of NEBs. A confocal laser microscope was used to make three-dimensional images of NEBs after NCAM immunostaining and the sp atial interaction between NEBs and the surrounding microenvironment wa s studied.