• Yoko Sakai, Shinji Kawahito, Kazumi Takaishi, Naoji Mita, Hiroyuki Kinoshita, Noboru Hatakeyama, Toshiharu Azma, Yutaka Nakaya, and Hiroshi Kitahata.
• Department of Anesthesiology, Tokushima University Hospital.
• J. Med. Invest. 2014 Jan 1; 61 (3-4): 278-84.

BackgroundPropofol causes vasodilation via endothelium-dependent and -independent mechanisms. Because endothelial function is impaired with aging, the effects of propofol on endothelium-dependent vasodilation might be altered by aging. The aim of this study was thus to determine the effects of aging on vascular responses to propofol.MethodsYoung (4-6 weeks old) or adult (16-25 weeks old) rats were anesthetized with sevoflurane. The thoracic aorta was dissected and cut into pieces 3-4 mm in length. In some rings, the endothelium was deliberately removed. The ring segment of the aorta was mounted for isometric force recording at a resting tension of 0.5-1.0 g in a 2 ml organ bath, containing Krebs-Ringer bicarbonate buffer. Arteries were precontracted with phenylephrine, and the function of endothelium was confirmed with acetylcholine. Then, we studied the concentration-dependent effects of propofol in endothelium-intact (control group) and -denuded aortic rings (denuded group), as well as those treated with N(ω)-nitro-L-arginine methylester (L-NAME group).ResultsRelaxation due to propofol was observed in the control groups of both young and adult rats in a concentration-dependent manner, but the magnitude of relaxation was significantly greater in young rats. In addition, in young rats, relaxation due to propofol was significantly and equally reduced in both L-NAME and denuded groups at all propofol concentrations that we studied (10(-6)-10(-3) M). In adult rats, relaxation due to propofol was quite similar between control and L-NAME groups at all propofol concentrations, whereas it was significantly reduced in the denuded group.ConclusionThese results suggest that endothelium-derived nitric oxide plays an important role in propofol-induced vasodilation in young rats, but not in adult rats.

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