{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T20:07:34Z","timestamp":1791144454635,"version":"4.1.0"},"reference-count":0,"publisher":"American Physiological Society","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Cell Physiology"],"published-print":{"date-parts":[[1987,2,1]]},"abstract":"<jats:p> Ca2+-activated K+ channels with estimated single channel conductances of 127 +\/- 2 pS were identified in the apical cell membrane of clone A3 of cultured medullary thick ascending limb (MTAL) cells. Both Ba2+ and the scorpion toxin, charybdotoxin (CTX), are slow blockers of the channels. An application of 0.1 microM Ba2+ to the intracellular face caused a 50% reduction in fractional open time (fv). Ba2+ block is both concentration and voltage dependent. Concentrations of CTX as low as 2 nM in the extracellular solution caused a significant reduction in fv. Tetraethylammonium (TEA) and quinine are fast blockers of Ca2+-activated K+ channels in MTAL cells. TEA, 400 microM, in the extracellular solution caused a voltage-dependent reduction in channel amplitude, whereas it takes 10 mM in the intracellular solution to reduce channel amplitude by 30%. Micromolar amounts of quinine applied to the intracellular face caused the channels to flicker rapidly between open and blocked states. These results suggest that K+ channels in MTAL cells are homologous to those found in muscle cells, and that these blocking agents may be used to probe the nature of K+ conductances in several nephron segments. <\/jats:p>","DOI":"10.1152\/ajpcell.1987.252.2.c128","type":"journal-article","created":{"date-parts":[[2017,12,24]],"date-time":"2017-12-24T09:39:02Z","timestamp":1514108342000},"page":"C128-C137","source":"Crossref","is-referenced-by-count":75,"title":["Blocking agents of Ca2+-activated K+ channels in cultured medullary thick ascending limb cells"],"prefix":"10.1152","volume":"252","author":[{"given":"S. E.","family":"Guggino","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"W. B.","family":"Guggino","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"N.","family":"Green","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"B.","family":"Sacktor","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","container-title":["American Journal of Physiology-Cell Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.physiology.org\/doi\/pdf\/10.1152\/ajpcell.1987.252.2.C128","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T19:51:19Z","timestamp":1718653879000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.physiology.org\/doi\/10.1152\/ajpcell.1987.252.2.C128"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1987,2,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1987,2,1]]}},"alternative-id":["10.1152\/ajpcell.1987.252.2.C128"],"URL":"https:\/\/doi.org\/10.1152\/ajpcell.1987.252.2.c128","relation":{},"ISSN":["0363-6143","1522-1563"],"issn-type":[{"value":"0363-6143","type":"print"},{"value":"1522-1563","type":"electronic"}],"subject":[],"published":{"date-parts":[[1987,2,1]]}}}