全身・腎血行動態と血中および心筋・腎組織内カテコラミンに及ぼすα₁受容体遮断薬の影響

Abstract

A study was performed on anesthetized adult mongrel dogs to investigate changes in hemodynamics, plasma catecholamine concentrations, and catecholamine stores in the heart muscle and kidney induced by administration of a selective α₁-receptor blocking agent，bunazosin (Bu). To investigate the effects of Bu on systemic and renal hemodynamics, cardiac output (CO), renal blood flow (RBF), and renal cortical blood flow (RCBF) were measured with an electromagnetic flowmeter and regional blood flow-meter ; effects on noradrenaline (NAD) and adrenaline (AD) concentrations were measured by high-performance liquid chromatography. Intravenous administration of Bu at an intermediate dose (0.05 mg/kg) or a high dose (0.25 mg/kg) caused the following : 1) reductions in the aortic and renal blood pressure ; 2) a decrease in CO ; 3) decreases in RBF, RCBF, effective renal blood flow, and glomerular filtration rate ; 4) decreases in NAD concentrations in aortic, coronary sinus, and renal vein blood at the intermediate dose, but increases at the high dose. The concentrations of NAD stored in heart muscle and kidney increased at the intermediate dose，but were unchanged at the high dose ; 5) AD concentrations in aortic, coronary sinus, and renal vein blood increased to a greater extent at the intermediate dose than at the high dose. The increases in AD stores in heart muscle and kidney were almost the same as that seen in plasma AD concentration. The results suggest that the effects of Bu on systemic and renal hemodynamics varied with the dose, with alterations in plasma catecholamine concentrations and catecholamine stores in canine heart and kidney.