Changes in reactivity of the digital artery of the fallow deer, Dama dama, in summer and winter

摘要

The vasoreactivity of the digital artery of the fallow deer, Dama dama, has been examined. The artery was constricted by adrenoceptor agonists such as noradrenaline and L-phenylephrine, and dilated by histamine in an endothelium dependent, L-NAME sensitive manner. No evidence could be found for muscarinic receptors using acetylcholine and carbachol. Arteries collected in the cold winter of 1995 96 were either insensitive, or had a reduced sensitivity to the vasodillator action of histamine, compared with arteries collected in summer or in the mild winters of 1997/98 and 1998/99. The vasodilator response to forskolin was considerably reduced in the cold winter arteries compared with the warm winter arteries, whereas the vasoconstrictor action of ODQ was unchanged. It is considered that the changes seen in the cold winter arteries were triggered by the external temperature and not by seasonal changes.