Moderate Hypothermia Increases Donepezil-Induced Relaxation in Calf Cardiac Vein: The Role of Nitric Oxide

Abstract

At present very little is known about the vascular effects of donepezil. The aim of the present study was to evaluate the effects of donepezil on calf cardiac vein. The effects of hypothermia (to 28 ˚C) on the vasodilatation induced by donepezil (10-9 - 3x10-4 M) on carbachol (10-6 M) - pre-contracted calf cardiac vein and the role of nitric oxide in these effects were also analyzed. Donepezil induced concentration dependent relaxations on carbachol (10-6 M) - pre-contracted vein preparations. During hypothermia, the sensitivity to donepezil was significantly higher than at 37 ˚C. L-NAME-incubation decreased the sensitivity at both temperatures. These results suggest that hypothermia increased the sensitivity to donepezil furthermore, nitric oxide plays an essential role in the donepezil-induced relaxation in calf cardiac vein. Furthermore, the results of this study demonstrate for the first time that hpothermia-induced changes of donepezil in calf cardiac vein is independent of nitric oxide