<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Japp, Alan G</style></author><author><style face="normal" font="default" size="100%">Cruden, Nicholas L</style></author><author><style face="normal" font="default" size="100%">Amer, David A B</style></author><author><style face="normal" font="default" size="100%">Li, Vivienne K Y</style></author><author><style face="normal" font="default" size="100%">Goudie, Ewan B</style></author><author><style face="normal" font="default" size="100%">Johnston, Neil R</style></author><author><style face="normal" font="default" size="100%">Sharma, Sushma</style></author><author><style face="normal" font="default" size="100%">Neilson, Ilene</style></author><author><style face="normal" font="default" size="100%">Webb, David J</style></author><author><style face="normal" font="default" size="100%">Megson, Ian L</style></author><author><style face="normal" font="default" size="100%">Flapan, Andrew D</style></author><author><style face="normal" font="default" size="100%">Newby, David E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Vascular effects of apelin in vivo in man.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of the American College of Cardiology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008 Sep 9</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">52</style></volume><pages><style face="normal" font="default" size="100%">908-13</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">OBJECTIVES: This study was designed to establish the direct vascular effects of apelin in vivo in man. BACKGROUND: Apelin is the endogenous ligand for the previously orphaned G-protein-coupled receptor, APJ. This novel pathway is widely expressed in the cardiovascular system and is emerging as an important mediator of cardiovascular homeostasis. In pre-clinical models, apelin causes venous and arterial vasodilation. METHODS: Vascular effects of apelin were assessed in 24 healthy volunteers. Dorsal hand vein diameter was measured by the Aellig technique during local intravenous infusions (0.1 to 3 nmol/min) of apelin-36, (Pyr(1))apelin-13, and sodium nitroprusside (0.6 nmol/min). Forearm blood flow was measured by venous occlusion plethysmography during intrabrachial infusions of apelin-36 and (Pyr(1))apelin-13 (0.1 to 30 nmol/min) and subsequently in the presence or absence of a &quot;nitric oxide clamp&quot; (nitric oxide synthase inhibitor, L-N(G)-monomethylarginine [8 mumol/min], coinfused with nitric oxide donor, sodium nitroprusside [90 to 900 ng/min]), or a single oral dose of aspirin (600 mg) or matched placebo. RESULTS: Although sodium nitroprusside caused venodilation (p &lt; 0.0001), apelin-36 and (Pyr(1))apelin-13 had no effect on dorsal hand vein diameter (p = 0.2). Both apelin isoforms caused reproducible vasodilation in forearm resistance vessels (p &lt; 0.0001). (Pyr(1))apelin-13-mediated vasodilation was attenuated by the nitric oxide clamp (p = 0.004) but unaffected by aspirin (p = 0.7). CONCLUSIONS: Although having no apparent effect on venous tone, apelin causes nitric oxide-dependent arterial vasodilation in vivo in man. The apelin-APJ system merits further clinical investigation to determine its role in cardiovascular homeostasis.</style></abstract></record></records></xml>