Vascular Effects of Apelin In Vivo in Man

Vascular Effects of Apelin In Vivo in Man Alan G. Japp, Nicholas L. Cruden, David A. B. Amer, Vivienne K. Y. Li, Ewan B. Goudie, Neil R. Johnston, Sushma Sharma, Ilene Neilson, David J. Webb, Ian L. Megson, Andrew D. Flapan, David E. Newby Using the Aellig hand vein technique and forearm venous occlusion plethysmography, we aimed to establish the direct vascular effects of apelin in vivo in man. Apelin-36 and (Pyr1 )apelin-13 had no effect on dorsal hand vein diameter (p = 0.2) but both isoforms caused vasodilation in forearm resistance vessels (p < 0.0001). Apelin-mediated vasodilation was attenuated by the nitric oxide clamp (a balanced coinfusion of the nitric oxide synthase inhibitor, L- NG -monomethylarginine, and nitric oxide donor, sodium nitroprusside; p = 0.004) but unaffected by aspirin (p = 0.7). Although having no apparent effect on venous tone, apelin causes nitric oxide-dependent arterial vasodilation in vivo in man.