Effects of Cl- channel blockers on beta-adrenoceptor-mediated decreases in resting potential and intracellular Cl- activity in guinea-pig heart.
In order to find a more specific blocker of the cardiac Cl- channel, we examined the effects of anthracene-9-carboxylic acid (9AC) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) on the beta-adrenoceptor-mediated decreases in resting potential and intracellular chloride ion activity (aiCl) in guinea-pig papillary muscles by using Cl- ion selective microelectrodes. 9AC (1 mM) significantly inhibited the isoproterenol (1 microM)-induced decreases in resting potential and aiCl in quiescent preparations. However, 1 mM DIDS did not significantly affect the changes in aiCl and resting potential during beta-adrenergic stimulation. Thus, in cardiac cells, 9AC is a more potent blocker of the Cl- channels activated by beta-adrenergic stimulation than DIDS.
Shida
S
S
Department of Pharmacology, Hokkaido University School of Medicine, Sapporo, Japan.
Nakaya
H
H
Kanno
M
M
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000873:Anthracenes / Q000494:pharmacology*; D018118:Chloride Channels; D002712:Chlorides / Q000378:metabolism*; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins / Q000037:antagonists & inhibitors*; D009206:Myocardium / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*
D000873:Anthracenes; D018118:Chloride Channels; D002712:Chlorides; D008565:Membrane Proteins; D011943:Receptors, Adrenergic, beta; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; C010030:9-anthroic acid; D007545:Isoproterenol; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid