Distribution and development of rodlet cells in the gills and pseudobranch of the bass, Dicentrachus labrax (L)

Abstract

Rodlet cells in various stages of development were found in large numbers in the bass gill and pseudobranch. In the gill, rodlet cells were found in the epithelium at the base of the secondary lamellae and on the filament between adjacent lamellae, whilst in the pseudobranch they were found over the whole area of the secondary lamellae as well as in the filament epithelium.During early development, rodlet cells are characterised by their amorphous cell inclusions, prominent supranuclear Golgi complex and network of granular endoplasmic reticulum. Later, with formation of a fibrous border the arrangement of the cell organelles undergoes reorganisation; the endoplasmic reticulum becomes distended, numerous vesicles appear and the mitochondria aggregate in the apical region of the cell. One of the most striking features is the development of club‐shaped sacs containing electron dense cores, which are orientated towards the open apex of the cell.Various staining properties of rodlet cells for light and electron microscopy were compared with those of mucous cells found in the same tissues. Possible functions of the cell are discussed.