Effect of frusemide on Cl- channel in rat peritoneal mast cells

Abstract

Frusemide can be used as an antiasthma drug and appears to inhibit the release (conditioned by activation of Cl -channels) of mast cell proinflammatory mediators. We studied the cause of the effects of frusemide, checking its action on Cl -channels.The patch-clamp technique was used to study single-channel currents, and differences in electrical potential of the cellular membrane of rat peritoneal mast cells were measured.In inside-out configuration, outwardly-rectifying Cl -channels were identified whose conductance was 2.4/1.7 pS at positive and negative voltages. The results of this study suggest that frusemide can inhibit mast cell Cl -channels only via an indirect mechanism, which probably involves an inhibition of a Na + -K + -2Cl -symport.

Plasmodium falciparum likely encodes the principal anion channel on infected human erythrocytes

“…First, although a number of transporters in other systems are inhibited by furosemide, its affinity for other transporters varies over a wide range, with published inhibitory concentration (IC 50 ) values from nano-to millimolar. [20][21][22] Second, the data in Figure 1D were adequately fitted by the Michaelis-Menten equation (solid line), implicating a 1:1 stoichiometry of furosemide binding to PSAC and further supporting the overwhelming predominance of a single ion channel type.…”

An Anion Channel in Guinea Pig Gallbladder Epithelial Cells Is Highly Permeable to HCO−3

“…The patch-clamp technique and data analysis were applied as reported (25,29). We used microelectrodes with a resistance of 14 -18 M⍀.…”

Specific Inhibition of the Plasmodial Surface Anion Channel by Dantrolene

“…For example, furosemide inhibits multiple co-and counter-transporters and a diverse collection of ion channels (44,41,30,39). NPPB, although primarily used for its effects on anion channels, is also known to inhibit Ca ϩϩ channels, K ϩ channels, gap junctions, and cyclooxygenase (15,20,48,5).…”