ISSN:
1432-1424
Keywords:
amiloride
;
methylisobutyl amiloride
;
ethylisopropyl amiloride
;
Ca-activated K+ channels
;
inhibition
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary The effect of the K+-sparing diuretic amiloride and two of its hydrophobic analogs, methylisobutyl amiloride (MIA) and ethylisopropyl amiloride (EIPA), on Ca-activated K+ channels from renal microvillus membrane vesicles incorporated into planar lipid bilayers was investigated. Amiloride did not inhibit currents through Ca-activated K+ channels. MIA and EIPA, however, inhibited channel currents when added to both the internal and external solutions in concentrations between 10 and 250 μM. Furthermore, when dose-response data for channel inhibition were examined using Hill plots, Hill numbers of ≈ 1.5 were found for both blockers from both sides, suggesting that the mechanism of block involves multiple inhibitory binding sites. A simple kinetic scheme is proposed that can account for the results.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00231884
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