{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,4,25]],"date-time":"2025-04-25T04:12:35Z","timestamp":1745554355568,"version":"3.40.4"},"reference-count":1,"publisher":"S. Karger AG","issue":"4","license":[{"start":{"date-parts":[[1998,1,1]],"date-time":"1998-01-01T00:00:00Z","timestamp":883612800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"},{"start":{"date-parts":[[1998,1,1]],"date-time":"1998-01-01T00:00:00Z","timestamp":883612800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmacology"],"published-print":{"date-parts":[[1998]]},"abstract":"Both contractile and relaxant responses to tetrapentylammonium ions (TPA<sup>+<\/sup>) were studied in rat isolated mesenteric artery. TPA<sup>+<\/sup> (5\u201310\u00a0\u00b5mol\/l) caused a sustained increase of muscle tension. The contractile effect of TPA<sup>+<\/sup> (10\u00a0\u00b5mol\/l) was dependent upon the presence of extracellular Ca<sup>2+<\/sup> but independent of the presence of endothelium. TPA<sup>+<\/sup> (10\u201350\u00a0\u00b5mol\/l) induced biphasic contraction, and the amplitude of peak and sustained tension decreased with increasing TPA<sup>+<\/sup> concentration. TPA<sup>+<\/sup> (100\u2013300\u00a0\u00b5mol\/l) only produced monophasic contraction. TPA<sup>+<\/sup> (50\u00a0\u00b5mol\/l) abolished the transient contraction induced by caffeine (10\u00a0mmol\/l) or phenylephrine (1\u00a0\u00b5mol\/l) in the absence of extracellular Ca<sup>2+<\/sup>. Nifedipine and verapamil concentration-dependently reduced the TPA<sup>+<\/sup>-induced contraction with respective IC<sub>50<\/sub> values of 1.34 \u00b1 0.24 and 9.46 \u00b1 1.36\u00a0nmol\/l, these values were similar to 1.35 \u00b1 0.21 and 16.07 \u00b1 1.71\u00a0nmol\/l, respectively, for the inhibitory effects of nifedipine and verapamil on the high K<sup>+<\/sup> (60\u00a0mmol\/l)-induced contraction. TPA<sup>+<\/sup> (>10 \u00b5mol\/l) concentration-dependently reduced the phenylephrine (1\u00a0\u00b5mol\/l)-, U46619 (30\u00a0nmol\/l)-, endothelin I (10\u00a0nmol\/l)- and high K<sup>+<\/sup> (60\u00a0mmol\/l)-induced sustained tension with respective IC<sub>50<\/sub> values of 53.7 \u00b1 9.5, 31.9 \u00b1 5.3, 30.9 \u00b1 3.4 and 20.9 \u00b1 2.8\u00a0\u00b5mol\/l. The present results indicate that TPA<sup>+<\/sup> at low concentrations could contract the arterial smooth muscle probably through promoting Ca<sup>2+<\/sup> influx. At higher concentrations (>20\u00a0\u00b5mol\/l), TPA<sup>+<\/sup> relaxes arterial smooth muscle probably through inhibition of both nifedipine-sensitive Ca<sup>+<\/sup> channels and internal Ca<sup>2+<\/sup> release. TPA<sup>+<\/sup>, unlike other quaternary ammonium ions, could therefore act at multiple sites in arterial smooth muscle.<\/jats:p>","DOI":"10.1159\/000028241","type":"journal-article","created":{"date-parts":[[2003,4,15]],"date-time":"2003-04-15T09:24:25Z","timestamp":1050398665000},"page":"188-195","source":"Crossref","is-referenced-by-count":2,"title":["Contractile and Relaxant Effects of Tetrapentylammonium Ions in Rat Isolated Mesenteric Artery"],"prefix":"10.1159","volume":"57","author":[{"given":"K.H.","family":"Kwok","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"N.W.K.","family":"Chan","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C.W.","family":"Lau","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu","family":"Huang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[1998,9,17]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","DOI":"10.1016\/0306-4522(88)90033-4"}],"container-title":["Pharmacology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/28241","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/28241","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,24]],"date-time":"2025-04-24T04:14:48Z","timestamp":1745468088000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000028241"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1998]]},"references-count":1,"journal-issue":{"issue":"4","published-online":{"date-parts":[[1998,10,1]]}},"URL":"https:\/\/doi.org\/10.1159\/000028241","archive":["Portico"],"relation":{},"ISSN":["0031-7012","1423-0313"],"issn-type":[{"type":"print","value":"0031-7012"},{"type":"electronic","value":"1423-0313"}],"subject":[],"published":{"date-parts":[[1998]]}}}