KHODABANDEH, S.; TALAEI, R.*; Univ. of Tarbiat Modarres, Tehran, IRAN and UMII, Montpellier, FRANCE; Univ. of Tarbiat Modarres, Tehran, IRAN : Immunocytochemical localization of Na/K-ATPase in the gut of the Zygopteran larvae (Odonata)

Damselflies (Zygopteran) are an interesting group of insects because their larvae are fully aquatic while the adults are terrestrial. Insects larvae living in freshwater are generally hyper-osmotic to their environment and in this condition, water tends to pass through the cuticle (in larvae stages), gill, and gut into insects. They are thus faced with a continuous osmotic inflow of water and with a continuous loss of ions. Na/K-ATPase is one of the most important ion-transporting enzymes enabling the use of ATP as a source of energy for ion transport with Na/K exchange pump across epithelial membranes. Immunolocalization of the Na/K-ATPase was performed through immunofluorescence light microscopy using a mouse monoclonal antibody IgGα5 raised against the α-subunit of the chicken Na/K-ATPase. Immunofluorescence microscopy showed consistent results within treatment groups. In thin sections, no specific fluorescence staining was observed in the cells of the foregut and the midgut regions. Na/K-ATPase was found in the malpighian tubule and hindgut epithelium. A consistently high immunoreactivity was observed in the lumen sides of the malpighian tubule cells. In rectal pads of hindgut a positive and strong fluorescence was found in basolateral sides of cells. These results suggest that: i)using of this antibody is a useful method for locating of Na/K-ATPase in the insects tissues; ii)the malpighian tubules and the rectal pads of hindgut are involved in osmotic hyper-regulation, thus zygopteran larvae are capable to producing a hypo-osmotic absorbate from the rectal lumen.