{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,16]],"date-time":"2026-03-16T10:42:38Z","timestamp":1773657758502,"version":"3.50.1"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"3","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1984,3,15]]},"abstract":"<jats:p>The role of changes in cytoplasmic free calcium, [Ca2+]i, in the responses to platelet-activating factor (PAF) was studied in human platelets loaded with the fluorescent calcium indicator, quin2. In the presence of 1 mM external calcium, PAF raised [Ca2+]i 8-10-fold in a few seconds to peak near 1 microM. [Ca2+]i then declined over several minutes towards the basal level. In the absence of external calcium there was a much smaller increase in [Ca2+]i of similar pattern. These findings suggest that PAF increases [Ca2+]i partly by discharge of internal Ca2+, but mainly by stimulated influx. Blockade of cyclo-oxygenase with aspirin only slightly reduced the [Ca2+]i changes, indicating that thromboxane A2 is not a major mediator of the calcium movements. In control conditions PAF could stimulate shape-change, aggregation and secretion. Aggregation and secretion were roughly halved by blockade of cyclo-oxygenase. Shape-change and secretion still occurred under conditions where the [Ca2+]i rise was small or suppressed, indicating a role for intracellular activators other than Ca2+. The possible involvement of products of phosphoinositide breakdown is discussed.<\/jats:p>","DOI":"10.1042\/bj2180819","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T20:41:04Z","timestamp":1439239264000},"page":"819-827","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":148,"title":["Stimulus-response coupling in human platelets. Changes evoked by platelet-activating factor in cytoplasmic free calcium monitored with the fluorescent calcium indicator quin2"],"prefix":"10.1042","volume":"218","author":[{"given":"T J","family":"Hallam","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A","family":"Sanchez","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"T J","family":"Rink","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/218\/3\/819\/581597\/bj2180819.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/218\/3\/819\/581597\/bj2180819.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,25]],"date-time":"2021-11-25T13:49:54Z","timestamp":1637848194000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/218\/3\/819\/16024\/Stimulus-response-coupling-in-human-platelets"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1984,3,15]]},"references-count":0,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1984,3,15]]}},"URL":"https:\/\/doi.org\/10.1042\/bj2180819","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[1984,3,15]]}}}