Meeting Abstract
7.11 Jan. 4 Ultrastructure and osmoregulatory function of the kidney in the Acipenser persicus at larval stage KHODABANDEH, Saber; TAGHIZADEH, Zahra; ABTAHI, Behroz*; CHARMANTIER, Guy; CHARMANTIER-DAURES, Mireille; Univ. of Tarbiat Modarres, Tehran, IRAN; Univ. of Montpellier II, France; Univ. of Montpellier II, France surp78@gmail.com
In freshwater fishes, the maintenance of blood osmolality and ion concentrations different from those of the external medium is based on active ion uptake (mainly Na+ and Cl-) by a Na+,K+ exchange pump. This pump is immunopositive for Na+,K+-ATPase. Ultrastructure of the cells and the localization of mitochondria rich cells were examined in the kidney of Iranian sturgeon, Acipenser persicus. Investigations were conducted through light and electron microscopy and through immunofluorescence for the Na+,K+-ATPase enzyme detection. Ultrastructuraly, the glomerular cells (podocytes) possess distinctive pedicels that extend to the basal membrane. Tight junctions are not observed, but desmosome-like junctions and large lateral channels are visible between the cells. The proximal tubule cells possess apical microvilli and basolateral membrane infoldings associated with mitochondria. The arrangement of apical microvilli is usually disturbed by the formation of cytoplasmic extrusions and globular vesicles which become detached and pass into the lumen. No immunofluorescence of Na+,K+-ATPase was detected in the glomerular cells. A week immunostaining was observed in the proximal tubule cells. A storage immunostaining of Na+,K+-ATPase was observed in the epithelial cells of the distal tubule and in the some cells of the bladder. In all immunostained cells, the basolateral region showed a much higher fluorescence. In conclusion, the tubule epithelial cells of kidney present morphological and enzymatic features of the osmoregulatory cells, particularly distal tubule cells. The kidney of the A. persicus , thus possesses active ion exchange capabilities and beside of their implication in excretion high participate in osmoregulation at larval stage.
