Somatostatin 14, prolactin, atrial natriuretic peptide, galanin and urotens
in II were found using immunohistochemistry in the urinary bladders of the
Antarctic fishes Trematomus bernacchii (Nototheniidae) and Chionodraca hama
tus (Channichthyidae) caught in the Ross Sea. The urinary bladders of the t
wo species showed a different histology in the epithelial layer. In T. bern
acchii the epithelium comprises a single type of columnar cells, while in C
. hamatus the columnar cells are restricted to the ventral portion of the b
ladder, and the dorso-lateral region is lined by cuboidal cells. No differe
nce in the intensity of the immunostaining was observed in the two cell typ
es; the only variation was a different distribution of the immunoreactions,
which were present in the whole cytoplasm in the cuboidal cells and restri
cted to the apical and/or basal portion of the columnar cells.