{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,23]],"date-time":"2025-10-23T11:13:34Z","timestamp":1761218014994},"reference-count":0,"publisher":"American Physiological Society","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Cell Physiology"],"published-print":{"date-parts":[[1991,12,1]]},"abstract":"<jats:p> Pigmented ciliary epithelial cells were studied using the whole cell voltage-clamp technique. Depolarizing steps from a holding potential of -80 mV resulted in a small initial inward current followed by a large outward current. Prolonged depolarizing voltage steps revealed inactivating and noninactivating components of outward current. Outward current was sensitive to the level of Ca2+ in the pipette and was increased by the calcium ionophore A23187; it was blocked by tetraethylammonium (TEA+), quinine, and 4-aminopyridine (4-AP). 4-AP blocked 70% of the outward current with a Ki of 7 x 10(-5) M, and part of the remaining current was abolished by Ni2+. Ni2+ caused a reduction in outward current by blocking IK(Ca) indirectly via decreasing Ca2+ entry through T-type Ca2+ channels. Separating Ni(2+)-sensitive from -insensitive outward conductance gives components that correspond notionally to IK(Ca) and IK(V), respectively. On this basis IK(Ca) represents approximately 28% of K+ outward current. Charybdotoxin blocked 26% of the outward conductance at very depolarized voltage steps as calculated from the slope of the current-voltage curve in this region. It is concluded that there are two major components to the outward current: IK(V), an inactivating voltage-sensitive K+ current, and IK(Ca), which is dependent on the entry of Ca2+ through T-type Ca2+ channels and comprises approximately a quarter of the total K+ outward current under the conditions described. Because of their relative voltage-activation properties, IK(Ca) will be the more important in terms of K+ transport and the secretion of aqueous humor by the ciliary epithelium. <\/jats:p>","DOI":"10.1152\/ajpcell.1991.261.6.c1055","type":"journal-article","created":{"date-parts":[[2017,12,24]],"date-time":"2017-12-24T13:24:43Z","timestamp":1514121883000},"page":"C1055-C1062","source":"Crossref","is-referenced-by-count":11,"title":["Two outward K+ currents in bovine pigmented ciliary epithelial cells: IK(Ca) and IK(V)"],"prefix":"10.1152","volume":"261","author":[{"given":"T. J.","family":"Jacob","sequence":"first","affiliation":[{"name":"Department of Physiology, University of Wales, Cardiff, United Kingdom."}],"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.1991.261.6.C1055","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T19:46:25Z","timestamp":1718653585000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.physiology.org\/doi\/10.1152\/ajpcell.1991.261.6.C1055"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1991,12,1]]},"references-count":0,"journal-issue":{"issue":"6","published-print":{"date-parts":[[1991,12,1]]}},"alternative-id":["10.1152\/ajpcell.1991.261.6.C1055"],"URL":"https:\/\/doi.org\/10.1152\/ajpcell.1991.261.6.c1055","relation":{},"ISSN":["0363-6143","1522-1563"],"issn-type":[{"value":"0363-6143","type":"print"},{"value":"1522-1563","type":"electronic"}],"subject":[],"published":{"date-parts":[[1991,12,1]]}}}