title: Microtubules in the "chloride cell" of the gill and disruptive effects of colchicine on the salt balance of the sea water adapted Mugil capito.
abstract: Electron-microscopic examination of the gill of the grey mullet, Mugil capito adapted to sea water, reveals the presence of numerous microtubules in the apical region of the mitochondria-rich cells. No microtubules are found in other types of epithelial cell. Exposure of the fish to colchicine  (10(-4)M) for four hours induces a 20% increase of plasma Na and Cl. Colchicine leaves the water permeability of the gill unchanged but Cl and Na exchange fluxes are inhibited by 30-50% and the gill potential pattern is altered. Salt gain replaces salt excretion across the gill. The K dependent Na and Cl efflux components, independent of the gill potential shift produced by K, are totally inhibited by colchicine. Exposure to lumicolchicine is not followed by a significant change of these Na and Cl efflux-components and potential pattern. The possibility that microtubules intervene in the salt excretion process across the chloride cells is discussed.
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism*; D003078:Colchicine / Q000494:pharmacology* / Q000528:radiation effects; D005399:Fishes / Q000378:metabolism*; D005618:Fresh Water; D005880:Gills / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008870:Microtubules / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D011188:Potassium / Q000494:pharmacology; D012623:Seawater; D012964:Sodium / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D002712:Chlorides; D012964:Sodium; D011188:Potassium; D003078:Colchicine