2-B-P-053 〇猪瀬 柊斗¹、永澤 悦伸¹、佐藤 啓^1,2、佐久間 清^1,3、千葉 達夫^1,3、相本 恵美¹、高原 章¹ Shuto Inose¹, Yoshinobu Nagasawa¹, Akira Sato^1,2, Kiyoshi Sakuma^1,3, Tatsuo Chiba^1,3, Megumi Aimoto¹, Akira Takahara^{1 1}東邦大・薬・薬物治療、²東邦大医療セ・佐倉・薬剤、³東邦大医療セ・大橋・薬剤 ¹Dept. Pharmacol. Therap., Fac. Pharmaceut. Sci. Toho Univ., ²Dept. Pharm. Toho Univ. Sakura Hosp., ³Dept. Pharm. Toho Univ. Ohashi Hosp. We have shown that arterial elasticity can be acutely modified by vasoactive drugs in rabbits. To clarify the functional role of the heart in the regulation of arterial elasticity in vivo, we analyzed the effects of cardiotonic glycoside digoxin on arterial elasticity in rabbits using the stiffness parameter β of the aortic (aortic β) and femoral arterial (femoral β) regions by measuring blood pressures at the right brachial artery, aortic bifurcation and tibial artery, electrocardiogram and phonocardiogram. Intravenous administrations of digoxin (0.03, 0.1, and 0.3 mg/kg) increased blood pressure, and carotid and femoral arterial blood flow in a dose-dependent manner. Digoxin increased femoral β in a dose-dependent manner, whereas it decreased aortic β. Meanwhile, vascular resistance was unaffected by digoxin. The current results of decreased arterial elasticity in the femoral artery region and increased aortic elasticity by digoxin at cardiotonic doses were similar to our previous study with β₁-adrenergic receptor agonist dobutamine, suggesting that cardiotonic drugs' actions can affect arterial elasticity independently of direct action on vascular smooth muscle.