Osmoregulation In The Antarctic Teleost Histiodraco Velifer

In the Antarctic summer, Histiodraco velifer, a bentic species, migrates in search of food from a dense and salted environment to the more diluted water of the melting ice of the surface, its osmoregulatory mechanisms need therefore a constant and accurate adaptation. Two ion transport systems were studied by immunohistochemistry, the Na+-K+-Cl- cotransport and the Na+/K(+)ATPase. The enzymes presence in the cells of urinary bladder and gills was correlated to the density of mitochondria revealed by the antibody to the inner mitochondrial membrane (AMA). Na+/K(+)ATPase positivity was localised at the baso lateral sides of the cells. A Na+/K+/Cl- cotransporter protein was also immunolocalised in the same cells that also showed immunopositivity for the antibody against the mitochondrail inner membrane. Two osmoregulatory peptides, somatostatin and prolactin, were also localised in the interlamellar space of the gills and in the urinary bladder epithelium.