A light microscopic study of the action of sodium orthovanadate on the gills of fresh-water and sea-water eels (Anguilla anguillaL.)

Gills of fresh-water and sea-water eels were perfused at a constant pressure with physiological Ringer containing 10−6M sodium orthovanadate and examined by light microscopy. The secondary gill filaments were markedly vasoconstricted in both freshwater and sea-water fish although the peripheral blood route around the secondary filaments was unaffected. The central venous space in the primary filament was largely unaffected. Significant constriction of both afferent and efferent arteries on the primary filament occurred. We conclude that orthovanadate vasoconstricts eel gills mainly at the level of the secondary filaments. The study also emphasizes that chloride cells are located on both the primary and secondary filaments of fresh-water gills but solely on the primary filaments of sea-water gills.