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. 1968 Mar;195(2):317–330. doi: 10.1113/jphysiol.1968.sp008460

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

P J Bentley
PMCID: PMC1351665  PMID: 5647323

Abstract

1 Amiloride inhibits Na transport and short-circuit current (SCC) across the toad bladder. It is 1000 times more active at the mucosal than serosal surface. The lowest effective concentration was 10-7 M.

2. The inhibition was non-competitive with the sodium on the mucosal side of the bladder.

3. Vasopressin, cyclic adenosine monophosphate (AMP) and aldosterone increased Na transport and SCC across the bladder and these effects were inhibited by amiloride.

4. The antagonism of amiloride for vasopressin was non-competitive.

5. Amphotericin B also increases Na transport across the bladder but its action was not changed by amiloride.

6. Amiloride was without effects on SCC and diffusion potentials in bladders metabolically inhibited with CN- and iodoacetic acid (IAA).

7. Neither plasma albumin, Ca2+ nor adenosine triphosphate (ATP) altered the effects of amiloride.

8. The only structural analogue of amiloride found to reduce SCC similarly was guanidine which was 1000 times less active. Pyrazine and a substituted pyrazine analogue were without effect. Neither guanidine nor the substituted pyrazine compound were competitive with amiloride.

9. Amiloride had no effect on the osmotic permeability of the toad bladder either in the presence or absence of vasopressin.

10. Na transport across the toad colon was also reduced by 10-5 M amiloride at the mucosal surface.

11. The possible mechanism of action of amiloride is discussed.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. BENTLEY P. J. The effects of neurohypophysial extracts on the water transfer across the wall of the isolated urinary bladder of the toad Bufo marinus. J Endocrinol. 1958 Sep;17(3):201–209. doi: 10.1677/joe.0.0170201. [DOI] [PubMed] [Google Scholar]
  2. BONTING S. L., CANADY M. R. NA-K ACTIVATED ADENOSINE TRIPHOSPHATASE AND SODIUM TRANSPORT IN TOAD BLADDER. Am J Physiol. 1964 Nov;207:1005–1009. doi: 10.1152/ajplegacy.1964.207.5.1005. [DOI] [PubMed] [Google Scholar]
  3. Baer J. E., Jones C. B., Spitzer S. A., Russo H. F. The potassium-sparing and natriuretic activity of N-amidino-3,5-diamino-6-chloropyrazinecarboxamide hydrochloride dihydrate (amiloride hydrochloride). J Pharmacol Exp Ther. 1967 Aug;157(2):472–485. [PubMed] [Google Scholar]
  4. CRABBE J. Stimulation of active sodium transport by the isolated toad bladder with aldosterone in vitro. J Clin Invest. 1961 Nov;40:2103–2110. doi: 10.1172/JCI104436. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Cofré G., Crabbé J. Active sodium transport by the colon of Bufo marinus: stimulation by aldosterone and antidiuretic hormone. J Physiol. 1967 Jan;188(2):177–190. doi: 10.1113/jphysiol.1967.sp008132. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Crabbé J., De Weer P. Action of aldosterone and vasopressin on the active transport of sodium by the isolated toad bladder. J Physiol. 1965 Oct;180(3):560–568. doi: 10.1113/jphysiol.1965.sp007717. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. FRAZIER H. S., DEMPSEY E. F., LEAF A. Movement of sodium across the mucosal surface of the isolated toad bladder and its modification by vasopressin. J Gen Physiol. 1962 Jan;45:529–543. doi: 10.1085/jgp.45.3.529. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Herrera F. C. Action of ouabain on sodium transport in the toad urinary bladder. Am J Physiol. 1966 May;210(5):980–986. doi: 10.1152/ajplegacy.1966.210.5.980. [DOI] [PubMed] [Google Scholar]
  9. KELLER A. R. A HISTOCHEMICAL STUDY OF THE TOAD URINARY BLADDER. Anat Rec. 1963 Nov;147:367–377. doi: 10.1002/ar.1091470308. [DOI] [PubMed] [Google Scholar]
  10. Kao C. Y., Nishiyama A. Actions of saxitoxin on peripheral neuromuscular systems. J Physiol. 1965 Sep;180(1):50–66. [PMC free article] [PubMed] [Google Scholar]
  11. LEAF A., ANDERSON J., PAGE L. B. Active sodium transport by the isolated toad bladder. J Gen Physiol. 1958 Mar 20;41(4):657–668. doi: 10.1085/jgp.41.4.657. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. LICHTENSTEIN N. S., LEAF A. EFFECT OF AMPHOTERICIN B ON THE PERMEABILITY OF THE TOAD BLADDER. J Clin Invest. 1965 Aug;44:1328–1342. doi: 10.1172/JCI105238. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Leaf A. Transepithelial transport and its hormonal control in toad bladder. Ergeb Physiol. 1965;56:216–263. [PubMed] [Google Scholar]
  14. NARAHASHI T., MOORE J. W., SCOTT W. R. TETRODOTOXIN BLOCKAGE OF SODIUM CONDUCTANCE INCREASE IN LOBSTER GIANT AXONS. J Gen Physiol. 1964 May;47:965–974. doi: 10.1085/jgp.47.5.965. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. ORLOFF J., HANDLER J. S. The similarity of effects of vasopressin, adenosine-3',5'-phosphate (cyclic AMP) and theophylline on the toad bladder. J Clin Invest. 1962 Apr;41:702–709. doi: 10.1172/JCI104528. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. PORTER G. A., EDELMAN I. S. THE ACTION OF ALDOSTERONE AND RELATED CORTICOSTEROIDS ON SODIUM TRANSPORT ACROSS THE TOAD BLADDER. J Clin Invest. 1964 Apr;43:611–620. doi: 10.1172/JCI104946. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. SKOU J. C. ENZYMATIC BASIS FOR ACTIVE TRANSPORT OF NA+ AND K+ ACROSS CELL MEMBRANE. Physiol Rev. 1965 Jul;45:596–617. doi: 10.1152/physrev.1965.45.3.596. [DOI] [PubMed] [Google Scholar]
  18. USSING H. H., ZERAHN K. Active transport of sodium as the source of electric current in the short-circuited isolated frog skin. Acta Physiol Scand. 1951 Aug 25;23(2-3):110–127. doi: 10.1111/j.1748-1716.1951.tb00800.x. [DOI] [PubMed] [Google Scholar]

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