Electrophysiologic study of the cortical collecting tubule of the rabbit

摘要: Electrophysiologic study of the cortical collecting tubule rabbit. Previous in vitro microperfusion studies have shown that under various circumstances transepithelial potential difference (PD) may be oriented either lumen-negative or lumen-positive. The present examines origin lumen-positive PD (1) tubules obtained from rabbits on a high sodium chloride diet and (2) with originally PDs which were made positive by substitution choline transport inhibition ouabain. In addition, another group given deoxycorticosterone acetate (DOCA), 5mg i.m., for 1 week perfused low perfusate (5 to 10mM). Chloride concentration collected fluid was measured used calculate whether passive equilibrium across tubules. PD, replacement methyl sulfate bath completely obliterated (+6.9 ± 1.0mV before -1.6 1.3 after substitution). Furosemide 10 -5 M -4 had no effect whereas acetazolamide (10 bath) produced significant decrease +9.3 1.2 mV +3.3 0.8 mV. Varying ambient pH 6.7 7.5 altering Pco 2 consistent effect. Finally, showed every studied there large between (mean = 25 6.5mV). Thus, all accomplished net against gradient excess predicted driving forces. It is concluded exhibits active certain responsible this sensitive but not furosemide. Etude electrophysiologique du canal collecteur lapin. Les etudes anterieures par ont montre que dans diverses circonstances la de potentiel transepitheliale comporte une positivite ou negativite luminale. Ce travail etudie l'origine luminale des collecteurs obtenus lapins soumis alimentation riche en sodium, et dont lumiere est initialement negative puis rendue au l'inhibition l'ouabaine. De plus, un autre groupe traites l'acetate desoxycorticosterone pendant semaine, ete perfuse avec solution pauvre chlore mM). La le liquide collecte mesuree utilisee pour determiner, calcul, possibilite d'un equilibre passif travers paroi tubulaire. Dans les electro-positive, CH 3 SO 4 bain abolit (+6,9 1,0mV avant 1,6 1,3 apres Le furosemide n'a pas d'effet sur alors l'acetazolamide bain) determine diminution significative +9,3 1,2 +3,3 0,8 modification ambiant 6,7 7,5 obtenue variations Pco2 net. Enfin l'etude l'equilibre montre, chaque etudie, importante entre d'equilibre (moyenne, 6,5mV). Donc tous accomplissent chlore, contre concentration, exces rapport ce qui peut etre calcule forces passives. Il conclu exerce actif qui, certaines conditions, responsable d'une electropositivite Cette sensible mais non