The reversibility of the respiratory inhibition in gills and the ultrastructural changes in chloride cells from the rotenone-poisoned marine teleost, Gadus callarias L

Abstract

The fine structure of chloride cells from untreated and rotenone-treated fish ( Gadus callarias)) has been studied. The micrographs of untreated cells show a dense population of microvesicles in the apical portion of these cells. It is assumed that these microvesicles, probably containing ions, disintegrate behind the apical plasma membrane, creating a granular cytoplasm. The folding of the apical cytoplasm is correlated with the excretory activity of the chloride cells. The granular apical cytoplasm seems to coincide with the site of a silverchloride precipitate found in the salt-water-adapted Fundulus heteroclitus [26]. Channels converging to the apical cavity have tight junctions at their lumenal ends. This indicates that they do not function as secretory ducts. The ultrastructure of the rotenone-treated cells suggests a mechanism associating respiratory inhibition in gill filaments with a concomitantly reduced ion transport. It has been found that fish gills are able to recover from a respiratory inhibition of up to 50 per cent on exposure of the fish to rotenone-free water for 1 hr after the period of poisoning. An heterogenous population of mitochondria is observed in cells of recovered gills. Folding of the apical membrane is observed only occasionally.