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Carbonic anhydrase in the rabbit epididymis
Abstracts
831
EF9
EF 10 CARBONIC ANHYDRASEIN THE RABBITEPIDIDYMIS. THE STRUCTURKOF THK EPITHELIUM Na+ CHANNEL E. Ekstedt,Y. Ridderstrale*, A. Jansson and OF PIG KIDNEY.C. Frelin,P. Barbry,0. ChasL. Plaen, Depts of Anatomyand Histologyand sande and M. Lazdunski,Centre de Biochimie of *AnimalPhysiology,SwedishUniv. of Agri- du CNRS, Part Valrose, 06034 Nice Cedex, culturalSciences,S-750 07 Uppsala,Sweden. France. The distributionof carbonic anhydrase (CA) The pharmacological propertiesof the epithewas studiedusing a cobaltprecipitation method. In all seomentsof the epididvmal duct some cells showedstrongcytiplasmic stain- The best amilorideanalogwas phenamil. Pheing. In the terminalsegmentthe basal cells namil was tritiated at a high radioactive also had cytoplasmicactivity.The majority specificactivityand used to titrate the of the cells in the middle segment were in- binding sites in intactand solubilized mempharmacological protenselystainedin theirapicalpart (includ- brane preparations.JThe ing the stereocilia). They also had many va- perties of the [ H] phenamil binding sites cuoles with membrane CA activityand small were found to $e identical to those of the intenselystainedgranulesassociatedto the epithelium N$ channel. A two step purificasites was vacuoles. The epididymis is activein the tion of the [ H] phenamil binding absorptionof both particulatematerial and set up and reSulted in a 1100 fold purificafluid as well as acidification of the luminal tion of the Na channel with a yield of 15%. experiments into liposomes of fluid.The participation of CA in acidifica- Reconstitution tion and bicarbonate resorption is well the purified material indicate #at the puriknown. Vacuoles and granules were common fied f H) phenamil receptor is able t$ catawhere absorptionof particulate materialoc- lyze the electrogenic transport of Na , The properties of the transpor$ curred,and the findingof CA in these sites phar~cological to those of the native Na may indicate a function for the enzymein are identical this process. channel.
EF 11 THE TIGHT JUNCTION: A REGULATING UNIT OF TRANSTRT IN LEAKY EPITHELIA?M2 Fromm, C.E. Palant , U. Hegel,C.J. Bentfel Clin. Physiol., Fr. yniv. Berlin,FRG; UCLA Sch. Med., CA, USA; ECU GreenvilleSch. Med., NC, USA.
El?12 FUNCTION+AND $lORPHOLOGY OF THB PARIETAL CELL AFTER H , K -ATPaseBLOCKADEBY OMEPRAZOLE. J. Fryklund,H.F. Helander,B. Elanderand B. Wallmark, Hlssle GastrointestinalResearch Laboratories, S-431 83 Molndal,Sweden.
Epithelialtight junctions (TJ) are mostly The substituted benzimidazoleomeprazole considered as rather staticstructuresin- (omef inhibits gastric acid secretion by capableof functionaladaptation. However,as block$de+of the gastricprotonpump enzyme an experimentalapproach to alter the TJ, the H , K -ATPase.Rabbitswere given ome (10 Necturusgallbladders were mountedin Ussing- and 100 rrmol/kgs.c.) as a singledose or chambersand were exposedto mcosal protami- once daily for one week. Both doses increased the pH of the gastriccontentwhich indicates ne 6 ,uM. This resulted in (i) increased epiinhibitionof acid secretion. Secretagoguethelial resistance, (ii) decreased cation which is related selectivity, (iii) increased net water ab- induced oxygen consumption, (iv) no changes in apical membrane to acid secret n, and the rate of uptake of sorption, (AP)as well as voltage and fractional resistance,and (v) the w$ak Qase t8C-aminopyrine increased depth and strand number of TJ the H , K -ATPaseactivitywere inhibited in freeze fractures.All changeswere completed the gastricgland preparationsisolatedfrom within 10 min and were fully reversible. We the oxynticmucosaof the ome-treatedanisuggestthat protaminealtersTJ ultrastruc-mals. Light microscopyanalysisof biopsies ture and barrier functionthroughcellular showedthat the ome treatment increased the events involvingthe cytoskeleton.Apparent- volume density of the acid c~par~ents in ly, TJ are able to vary their structureand the gastricmucosa.After the treatment with permeabilityalso due to more physiologicome, no changescouldbe seen neitherin the concentration of the parietal cells nor in stiqi@i osmotic gradient, the H+, K -ATRase. [Ca 1) an!le&s may affecttransport%Z ky epithelia. It is unknownso far whether these stimuliact via a commonmechanism.
831
EF9
EF 10 CARBONIC ANHYDRASEIN THE RABBITEPIDIDYMIS. THE STRUCTURKOF THK EPITHELIUM Na+ CHANNEL E. Ekstedt,Y. Ridderstrale*, A. Jansson and OF PIG KIDNEY.C. Frelin,P. Barbry,0. ChasL. Plaen, Depts of Anatomyand Histologyand sande and M. Lazdunski,Centre de Biochimie of *AnimalPhysiology,SwedishUniv. of Agri- du CNRS, Part Valrose, 06034 Nice Cedex, culturalSciences,S-750 07 Uppsala,Sweden. France. The distributionof carbonic anhydrase (CA) The pharmacological propertiesof the epithewas studiedusing a cobaltprecipitation method. In all seomentsof the epididvmal duct some cells showedstrongcytiplasmic stain- The best amilorideanalogwas phenamil. Pheing. In the terminalsegmentthe basal cells namil was tritiated at a high radioactive also had cytoplasmicactivity.The majority specificactivityand used to titrate the of the cells in the middle segment were in- binding sites in intactand solubilized mempharmacological protenselystainedin theirapicalpart (includ- brane preparations.JThe ing the stereocilia). They also had many va- perties of the [ H] phenamil binding sites cuoles with membrane CA activityand small were found to $e identical to those of the intenselystainedgranulesassociatedto the epithelium N$ channel. A two step purificasites was vacuoles. The epididymis is activein the tion of the [ H] phenamil binding absorptionof both particulatematerial and set up and reSulted in a 1100 fold purificafluid as well as acidification of the luminal tion of the Na channel with a yield of 15%. experiments into liposomes of fluid.The participation of CA in acidifica- Reconstitution tion and bicarbonate resorption is well the purified material indicate #at the puriknown. Vacuoles and granules were common fied f H) phenamil receptor is able t$ catawhere absorptionof particulate materialoc- lyze the electrogenic transport of Na , The properties of the transpor$ curred,and the findingof CA in these sites phar~cological to those of the native Na may indicate a function for the enzymein are identical this process. channel.
EF 11 THE TIGHT JUNCTION: A REGULATING UNIT OF TRANSTRT IN LEAKY EPITHELIA?M2 Fromm, C.E. Palant , U. Hegel,C.J. Bentfel Clin. Physiol., Fr. yniv. Berlin,FRG; UCLA Sch. Med., CA, USA; ECU GreenvilleSch. Med., NC, USA.
El?12 FUNCTION+AND $lORPHOLOGY OF THB PARIETAL CELL AFTER H , K -ATPaseBLOCKADEBY OMEPRAZOLE. J. Fryklund,H.F. Helander,B. Elanderand B. Wallmark, Hlssle GastrointestinalResearch Laboratories, S-431 83 Molndal,Sweden.
Epithelialtight junctions (TJ) are mostly The substituted benzimidazoleomeprazole considered as rather staticstructuresin- (omef inhibits gastric acid secretion by capableof functionaladaptation. However,as block$de+of the gastricprotonpump enzyme an experimentalapproach to alter the TJ, the H , K -ATPase.Rabbitswere given ome (10 Necturusgallbladders were mountedin Ussing- and 100 rrmol/kgs.c.) as a singledose or chambersand were exposedto mcosal protami- once daily for one week. Both doses increased the pH of the gastriccontentwhich indicates ne 6 ,uM. This resulted in (i) increased epiinhibitionof acid secretion. Secretagoguethelial resistance, (ii) decreased cation which is related selectivity, (iii) increased net water ab- induced oxygen consumption, (iv) no changes in apical membrane to acid secret n, and the rate of uptake of sorption, (AP)as well as voltage and fractional resistance,and (v) the w$ak Qase t8C-aminopyrine increased depth and strand number of TJ the H , K -ATPaseactivitywere inhibited in freeze fractures.All changeswere completed the gastricgland preparationsisolatedfrom within 10 min and were fully reversible. We the oxynticmucosaof the ome-treatedanisuggestthat protaminealtersTJ ultrastruc-mals. Light microscopyanalysisof biopsies ture and barrier functionthroughcellular showedthat the ome treatment increased the events involvingthe cytoskeleton.Apparent- volume density of the acid c~par~ents in ly, TJ are able to vary their structureand the gastricmucosa.After the treatment with permeabilityalso due to more physiologicome, no changescouldbe seen neitherin the concentration of the parietal cells nor in stiqi@i osmotic gradient, the H+, K -ATRase. [Ca 1) an!le&s may affecttransport%Z ky epithelia. It is unknownso far whether these stimuliact via a commonmechanism.