Amiloride: a potent inhibitor of sodium transport across the toad bladder

摘要: 1 Amiloride inhibits Na transport and short-circuit current (SCC) across the toad bladder. It is 1000 times more active at mucosal than serosal surface. The lowest effective concentration was 10−7 M. 2. inhibition non-competitive with sodium on side of bladder. 3. Vasopressin, cyclic adenosine monophosphate (AMP) aldosterone increased SCC bladder these effects were inhibited by amiloride. 4. antagonism amiloride for vasopressin non-competitive. 5. Amphotericin B also increases but its action not changed amiloride. 6. without diffusion potentials in bladders metabolically CN− iodoacetic acid (IAA). 7. Neither plasma albumin, Ca2+ nor triphosphate (ATP) altered amiloride. 8. only structural analogue found to reduce similarly guanidine which less active. Pyrazine a substituted pyrazine effect. compound competitive amiloride. 9. had no effect osmotic permeability either presence or absence vasopressin. 10. colon reduced 10−5 M surface. 11. possible mechanism discussed.