Skin epithelial transport and structural relationships in naturally metamorphosing Pelobates syriacus.
The onset of active Na(+) transport and activated Cl(-) conductance (G(Cl)) across the skin epithelium of Pelobates syriacus was investigated during natural ontogenetic development. Structural features, including band three and Peanut lectin bindings were tested in parallel and structure-function relationships were attempted. The 22 specimens studied were divided into two tadpole, three juvenile, and two adult stages, corresponding to the Taylor-Kollros standard table, in accordance with external morphology of their developmental stage. Onset of transepithelial electrical potential and drop in conductance occurred abruptly, coinciding with metamorphosis climax of tadpoles into juveniles at about stage XXI of development. Amiloride-sensitive Na(+) transport occurred a little later at stage XXIII, followed by the appearance of activated Cl(-) conductance, G(Cl). Parallel structural examination showed that skin MR cells occurred upon metamorphosis, as the tadpole integument transformed into the adult epithelium and could be associated with the occurrence of activated G(Cl). It was not related temporally with the appearance of band three protein in MR cells. Our findings support the association of G(Cl) with MR cells, whereas band three may only be a corollary of G(Cl) and not necessarily essential for its manifestation.
Katz
Uri
U
Department of Biology, Technion, Israel Institute of Technology Haifa, Israel. bir02uk@tx.technion.ac.il
Rozman
Alexander
A
Gabbay
Shosh
S
D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte; D001001:Anura / Q000378:metabolism*; D001693:Biological Transport, Active; D001835:Body Weight; D002712:Chlorides / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D005712:Galvanic Skin Response; D007150:Immunohistochemistry; D017136:Ion Transport; D007814:Larva; D008675:Metamorphosis, Biological; D019887:Peanut Agglutinin; D012867:Skin / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
D001457:Anion Exchange Protein 1, Erythrocyte; D002712:Chlorides; D019887:Peanut Agglutinin; D012964:Sodium