On the range of α-adrenergic regulation of coronary vascular resistance

摘要: In order to obtain an estimate of the range α-adrenergic resistance regulation in coronary vascular system, following studies were performed: 15 anesthetized dogs circumflex artery was cannulated and perfused with above-normal constant pressure so that venous oxygen tension never fell below 40 mmHg. Thus, it possible eliminate influence metabolic factor regulating resistance. Furthermore, isolated isovolumetrically working guinea-pig hearts according Langendorff method. Stimulation, resp. blockade, α-receptors achieved by administering xylometazoline, phentolamine. Xylometazoline increased both insitu heart. Administering maximum doses dog led increase about 200%. This is equivalent a reduction conductance 50%. Phentolamine produced no significant effects Maximum dosage administered heart situ decrease 60%, elevation 170%. If we let control values be equal 100%, our experiments showed from 60% 200% 50%