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N-ethylmaleimide-inhibited electrogenic K+ secretion in the ampulla of the frog semicircular canal.
J Physiol. 1993 Feb; 461:451-65.JP

Abstract

1. The mechanisms of K+ secretion into endolymph were studied on a preparation of isolated semicircular canal with different pharmacological inhibitors. Three periods of 5 or 30 min were performed, the first as control, the second in the presence of the drugs added to the apical or the basolateral bathing solution, and the third as recovery. Apical fluid was sampled at the beginning and the end of each period, transepithelial potential was recorded, Na+, K+, and Cl- concentrations, and K+ efflux, with 86Rb+ as a tracer, were measured and K+ fluxes were calculated. 2. When both sides of the epithelium were bathed with perilymph-like solution, the epithelium absorbed Na+, secreted K+, and generated a lumen positive potential. 3. The ATPases inhibitors, ouabain (10(-5) and 10(-3) M) and N-ethylmaleimide (10(-4) and 10(-3) M) inhibited the electrogenic K+ secretion when added to the basolateral fluid. N-ethylmaleimide (10(-3) M) applied to the apical fluid during a 5 min period decreased the K+ influx by 43% and the transepithelial potential by 66%. Other ATPase inhibitors, harmaline (10(-3) M), omeprazole (10(-4) M), vanadate (10(-4) M and 10(-3) M), N,N'-dicyclohexylcarbodiimide (DCC, 10(-5) M), 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl, 5 x 10(-6) M and 5 x 10(-5) M), and bafilomycin (10(-7) M) did not affect the K+ transport nor the transepithelial potential when they were added to the apical fluid. 4. The Na(+)-K(+)-Cl- co-transporter inhibitor, bumetanide, decreased both the transepithelial potential and the K+ transport when added to the basolateral solution but not to the apical one. At 10(-6) M, bumetanide maximally decreased the K+ influx by about 60%. 5. K+ channel blockers, quinine (10(-4) M), TEA (5 x 10(-3) M), added to the apical solution and barium (2 x 10(-3) M) added to either the apical or the basolateral solutions, did not affect the K+ transport and the transepithelial potential. 6. The carbonic anhydrase inhibitor acetazolamide (10(-3) M) added to both apical and basolateral solutions did not affect the K+ transport and the transepithelial potential. 7. It is concluded that, in the ampulla of the semicircular canal, a basolateral Na(+)-K(+)-Cl- co-transporter energized by the Na+, K(+)-ATPase was involved for 60% in the K+ secretion into endolymph. The electrogenic K+ transport would partly depend on a N-ethylmaleimide-sensitive protein possibly located at the apical plasma membrane or intracellularly.

Authors+Show Affiliations

Department of Physiology, Faculté Xavier Bichat, Université Paris 7, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8394425

Citation

Ferrary, E, et al. "N-ethylmaleimide-inhibited Electrogenic K+ Secretion in the Ampulla of the Frog Semicircular Canal." The Journal of Physiology, vol. 461, 1993, pp. 451-65.
Ferrary E, Bernard C, Oudar O, et al. N-ethylmaleimide-inhibited electrogenic K+ secretion in the ampulla of the frog semicircular canal. J Physiol (Lond). 1993;461:451-65.
Ferrary, E., Bernard, C., Oudar, O., Loiseau, A., Sterkers, O., & Amiel, C. (1993). N-ethylmaleimide-inhibited electrogenic K+ secretion in the ampulla of the frog semicircular canal. The Journal of Physiology, 461, 451-65.
Ferrary E, et al. N-ethylmaleimide-inhibited Electrogenic K+ Secretion in the Ampulla of the Frog Semicircular Canal. J Physiol (Lond). 1993;461:451-65. PubMed PMID: 8394425.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - N-ethylmaleimide-inhibited electrogenic K+ secretion in the ampulla of the frog semicircular canal. AU - Ferrary,E, AU - Bernard,C, AU - Oudar,O, AU - Loiseau,A, AU - Sterkers,O, AU - Amiel,C, PY - 1993/2/1/pubmed PY - 1993/2/1/medline PY - 1993/2/1/entrez SP - 451 EP - 65 JF - The Journal of physiology JO - J. Physiol. (Lond.) VL - 461 N2 - 1. The mechanisms of K+ secretion into endolymph were studied on a preparation of isolated semicircular canal with different pharmacological inhibitors. Three periods of 5 or 30 min were performed, the first as control, the second in the presence of the drugs added to the apical or the basolateral bathing solution, and the third as recovery. Apical fluid was sampled at the beginning and the end of each period, transepithelial potential was recorded, Na+, K+, and Cl- concentrations, and K+ efflux, with 86Rb+ as a tracer, were measured and K+ fluxes were calculated. 2. When both sides of the epithelium were bathed with perilymph-like solution, the epithelium absorbed Na+, secreted K+, and generated a lumen positive potential. 3. The ATPases inhibitors, ouabain (10(-5) and 10(-3) M) and N-ethylmaleimide (10(-4) and 10(-3) M) inhibited the electrogenic K+ secretion when added to the basolateral fluid. N-ethylmaleimide (10(-3) M) applied to the apical fluid during a 5 min period decreased the K+ influx by 43% and the transepithelial potential by 66%. Other ATPase inhibitors, harmaline (10(-3) M), omeprazole (10(-4) M), vanadate (10(-4) M and 10(-3) M), N,N'-dicyclohexylcarbodiimide (DCC, 10(-5) M), 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl, 5 x 10(-6) M and 5 x 10(-5) M), and bafilomycin (10(-7) M) did not affect the K+ transport nor the transepithelial potential when they were added to the apical fluid. 4. The Na(+)-K(+)-Cl- co-transporter inhibitor, bumetanide, decreased both the transepithelial potential and the K+ transport when added to the basolateral solution but not to the apical one. At 10(-6) M, bumetanide maximally decreased the K+ influx by about 60%. 5. K+ channel blockers, quinine (10(-4) M), TEA (5 x 10(-3) M), added to the apical solution and barium (2 x 10(-3) M) added to either the apical or the basolateral solutions, did not affect the K+ transport and the transepithelial potential. 6. The carbonic anhydrase inhibitor acetazolamide (10(-3) M) added to both apical and basolateral solutions did not affect the K+ transport and the transepithelial potential. 7. It is concluded that, in the ampulla of the semicircular canal, a basolateral Na(+)-K(+)-Cl- co-transporter energized by the Na+, K(+)-ATPase was involved for 60% in the K+ secretion into endolymph. The electrogenic K+ transport would partly depend on a N-ethylmaleimide-sensitive protein possibly located at the apical plasma membrane or intracellularly. SN - 0022-3751 UR - https://www.unboundmedicine.com/medline/citation/8394425/N_ethylmaleimide_inhibited_electrogenic_K+_secretion_in_the_ampulla_of_the_frog_semicircular_canal_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0022-3751&date=1993&volume=461&spage=451 DB - PRIME DP - Unbound Medicine ER -