{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T03:24:30Z","timestamp":1777433070261,"version":"3.51.4"},"reference-count":15,"publisher":"S. Karger AG","issue":"5","license":[{"start":{"date-parts":[[2003,1,1]],"date-time":"2003-01-01T00:00:00Z","timestamp":1041379200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"},{"start":{"date-parts":[[2003,1,1]],"date-time":"2003-01-01T00:00:00Z","timestamp":1041379200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Neuroendocrinology"],"published-print":{"date-parts":[[2003]]},"abstract":"The frequency of spontaneous action potentials (SAP) is important in the regulation of hormone secretion. The decrease in K<sup>+<\/sup> conductance is known as a primary mechanism for increasing SAP frequency. To investigate the nature of K<sup>+<\/sup> channels that contribute to the frequency regulation of the SAP in rat clonal pituitary GH<sub>3<\/sub> cells, the effect of various K<sup>+<\/sup> channel blockers on the SAP and membrane currents were recorded using the patch-clamp technique. A classical inward rectifying K<sup>+<\/sup> channel blocker, Cs<sup>+<\/sup> (5 m<i>M<\/i>), caused an increase in firing frequency and depolarization in after-hyperpolarization (AHP) voltage. An <i>ether-a-go-go<\/i><i>(erg)<\/i> type K<sup>+<\/sup> channel blocker, E-4031 (5 \u00b5<i>M<\/i>), caused no significant effect on the SAP. Tetraethylammonium (TEA, 10 m<i>M<\/i>) decreased firing frequency and increased the duration of SAP. These effects were not changed by the presence of high concentration of Ca<sup>2+<\/sup> buffer (10 m<i>M<\/i> EGTA or BAPTA) in pipette solutions. In voltage-clamp experiments, Cs<sup>+<\/sup> and E-4031 did not affect outwardly rectifying K<sup>+<\/sup> currents, but significantly inhibited inwardly rectifying K<sup>+<\/sup> currents recorded in isotonic K<sup>+<\/sup> solution. However, the kinetics of Cs<sup>+<\/sup>-sensitive current and E-4031-sensitive current were distinctive: the time to peak was more immediate and the decay rate was slower in Cs<sup>+<\/sup>-sensitive current than in E-4031-sensitive current. These results imply that Cs<sup>+<\/sup> and E-4031 inhibit the distinct components of inwardly rectifying K<sup>+<\/sup> currents, and that the contribution of the Cs<sup>+<\/sup>-sensitive current can be immediate on repolarization and can last more effectively over pacemaking potential range than E-4031-sensitive current.<\/jats:p>","DOI":"10.1159\/000074447","type":"journal-article","created":{"date-parts":[[2003,12,19]],"date-time":"2003-12-19T09:25:47Z","timestamp":1071825947000},"page":"260-269","source":"Crossref","is-referenced-by-count":8,"title":["Role of K<sup>+<\/sup> Channels in Frequency Regulation of Spontaneous Action Potentials in Rat Pituitary GH<sub>3 <\/sub>Cells"],"prefix":"10.1159","volume":"78","author":[{"given":"Suk-Ho","family":"Lee","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eun Hae","family":"Lee","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shin Young","family":"Ryu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hyewhon","family":"Rhim","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hye-Jung","family":"Baek","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wonil","family":"Lim","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Won-Kyung","family":"Ho","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2003,12,8]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.274.11.7508"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.1038\/42815"},{"key":"ref3","doi-asserted-by":"publisher","DOI":"10.1038\/43072"},{"key":"ref4","doi-asserted-by":"publisher","DOI":"10.1038\/31960"},{"key":"ref5","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7793.1999.0401p.x"},{"key":"ref6","doi-asserted-by":"publisher","DOI":"10.1007\/s004240050356"},{"key":"ref7","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.physiol.48.1.515"},{"key":"ref8","doi-asserted-by":"publisher","DOI":"10.1016\/0306-4522(80)90117-7"},{"key":"ref9","doi-asserted-by":"publisher","DOI":"10.1159\/000054378"},{"key":"ref10","doi-asserted-by":"publisher","DOI":"10.1085\/jgp.67.6.621"},{"key":"ref11","doi-asserted-by":"publisher","DOI":"10.1016\/0014-5793(95)00527-G"},{"key":"ref12","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2826.2000.00447.x"},{"key":"ref13","doi-asserted-by":"publisher","DOI":"10.1210\/me.14.6.863"},{"key":"ref14","doi-asserted-by":"publisher","DOI":"10.1016\/S0006-8993(98)00964-0"},{"key":"ref15","doi-asserted-by":"publisher","DOI":"10.1085\/jgp.94.5.789"}],"container-title":["Neuroendocrinology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/74447","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/74447","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,24]],"date-time":"2025-04-24T03:53:00Z","timestamp":1745466780000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000074447"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2003]]},"references-count":15,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2003,11,1]]}},"URL":"https:\/\/doi.org\/10.1159\/000074447","archive":["Portico"],"relation":{},"ISSN":["0028-3835","1423-0194"],"issn-type":[{"value":"0028-3835","type":"print"},{"value":"1423-0194","type":"electronic"}],"subject":[],"published":{"date-parts":[[2003]]}}}