右室冠循環に及ぼすαおよびβアドレナリン作用の影響(実験的検討)

抄録

Alpha and beta-adrenergic effect on the coronary circulation of the right ventricle were studied in comparison with those of the left in anesthetized open chest dogs. Norepinephrine was administrated and the cardiac sympathetic nerve was stimulated with beta-blocker pretreatment to determine whether there was any difference in vasoconstriction between the right and left coronary arteries. When the right and left cardiac sympathetic nerves were stimulated, coronary vasoconstriction was considerably greater in the RCA than in the LAD, while coronary vasoconstriction induced by NE injection was greater in the LAD than in the RCA. These data indicated that the pre-synaptic alpha-adrenergic stimulation caused affected the RCA and LAD differently from the post-synaptic alpha-adrenergic stimulation as to the extent of coronary vasocostriction. With phentolamine pretreatment the nerve stimulation caused no difference in the rate of increase of mean coronary blood flow between the RCA and LAD, and the rate of increase of RVSP×HR was greater than that of LVSP×HR. These results indicate that cardiac sympathetic nerve stimulation affected the right ventricle more than the left mainly through beta-adrenoceptors. The response of the right ventricle to increased oxygen demand was possibly, in part, different from that of the left.