{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,8]],"date-time":"2026-03-08T23:40:28Z","timestamp":1773013228920,"version":"3.50.1"},"reference-count":0,"publisher":"American Physiological Society","issue":"5","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Cell Physiology"],"published-print":{"date-parts":[[1993,11,1]]},"abstract":"<jats:p> Single-channel recording techniques were used to identify and characterize the K+ channel activated by Ca(2+)-mediated secretory agonists in T84 cells. Carbachol (CCh; 100 microM) and taurodeoxycholate (TDC; 0.75 mM) stimulated oscillatory outward K+ currents. With K gluconate in bath and pipette, cell-attached single-channel K+ currents stimulated by CCh and ionomycin (2 microM) were inwardly rectified and reversed at 0 mV. The single-channel chord conductance was 32 pS at -90 mV and 14 pS at +90 mV. Similar properties were observed in excised inside-out patches in symmetric K+, permitting further characterization of channel properties. Partial substitution of bath or pipette K+ with Na+ gave a K(+)-to-Na+ selectivity ratio of 5.5:1. Channel activity increased with increasing bath Ca2+ concentration in the physiological range of 50-800 nM. Maximal channel activity occurred at intracellular pH 7.2 and decreased at more acidic or alkaline pH values. Extracellular charybdotoxin (CTX; 50 nM) blocked inward but not outward currents. Extracellular tetraethylammonium (TEA; 10 mM) reduced single-channel amplitude at all voltages. No apparent block of the channel was observed with extracellular Ba2+ (1 mM), apamin (1 microM), 4-aminopyridine (4-AP; 4 mM), quinine (500 microM), or glyburide (10 microM). Cytosolic quinine and 4-AP blocked both inward and outward currents, whereas Ba2+ blocked only outward currents. Apamin, CTX, TEA, and glyburide did not affect channel activity. The agonist activation and pharmacological profile of this inwardly rectified K+ channel indicate that it is responsible for the increase in basolateral K+ conductance stimulated by Ca(2+)-mediated agonists in T84 cells. <\/jats:p>","DOI":"10.1152\/ajpcell.1993.265.5.c1271","type":"journal-article","created":{"date-parts":[[2017,12,24]],"date-time":"2017-12-24T14:47:42Z","timestamp":1514126862000},"page":"C1271-C1280","source":"Crossref","is-referenced-by-count":58,"title":["Calcium-mediated agonists activate an inwardly rectified K+ channel in colonic secretory cells"],"prefix":"10.1152","volume":"265","author":[{"given":"D. C.","family":"Devor","sequence":"first","affiliation":[{"name":"Department of Physiology and Biophysics, University of Alabama atBirmingham 35294."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R. A.","family":"Frizzell","sequence":"additional","affiliation":[{"name":"Department of Physiology and Biophysics, University of Alabama atBirmingham 35294."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"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.1993.265.5.C1271","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T19:42:52Z","timestamp":1718653372000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.physiology.org\/doi\/10.1152\/ajpcell.1993.265.5.C1271"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1993,11,1]]},"references-count":0,"journal-issue":{"issue":"5","published-print":{"date-parts":[[1993,11,1]]}},"alternative-id":["10.1152\/ajpcell.1993.265.5.C1271"],"URL":"https:\/\/doi.org\/10.1152\/ajpcell.1993.265.5.c1271","relation":{},"ISSN":["0363-6143","1522-1563"],"issn-type":[{"value":"0363-6143","type":"print"},{"value":"1522-1563","type":"electronic"}],"subject":[],"published":{"date-parts":[[1993,11,1]]}}}