Capurro N L, Kent K M, Smith H J, Aamodt R, Epstein S E
Am J Cardiol. 1977 May 4;39(5):679-83. doi: 10.1016/s0002-9149(77)80128-8.
Regional coronary blood flow was determined with the radioactive microsphere technique 10 an 70 minutes and 2 1/2 and 5 hours after abrupt occlusion of the left anterior descending coronary artery in 12 closed chest sedated dogs. In six dogs, nitroglycerin, 200 to 400 microng/min, was infused intravenously 10 to 70 minutes after occlusion. Methoxamine was administered to return blood pressure and heart rate to prenitroglycerin levels. Ten minutes after occlusion (before treatment) collateral flow values and ischemic zone endocardial/epicardial flow ratios were equivalent in untreated (0.11+/-0.03 ml/min per g; 0.31+/-0.05) and treated dogs (0.14+/-0.02 ml/min per g; 0.29+/-0.03). In untreated dogs, collateral flow did not change over 5 hours; the endocardial/epicardial flow ratio was decreased at 5 hours (0.21+/-0.05, P less than 0.05). In contrast, in treated dogs, collateral flow and the endocardial/epicardial flow ratio were increased at 70 minutes (0.27+/-0.04 ml/min per g, P less than 0.05; 0.53+/-0.10, P less than 0.05). Most importantly, collateral flow remained elevated 5 hours after occlusion (0.26+/-0.03 ml/min per g, P less than 0.05) although treatment was discontinued 70 minutes after occlusion. Hence, collateral flow was unchanged over 5 hours of occlusion in untreated dogs, but short-term treatment with nitroglycerin and methoxamine resulted in a sustained increase in collateral flow. These findings may be a result of stimulation by nitroglycerin and methoxamine of the spontaneous rate at which intrinsic collateral function increases after ischemia. Alternatively, nitroglycerin and methoxamine may maintain cell viability until collateral vessels develop spontaneously.
采用放射性微球技术，在12只胸部封闭且已镇静的犬身上，于左冠状动脉前降支突然闭塞后10分钟、70分钟、2.5小时和5小时测定局部冠状动脉血流量。在6只犬中，闭塞后10至70分钟静脉输注硝酸甘油，剂量为200至400微克/分钟。给予甲氧明使血压和心率恢复到使用硝酸甘油前的水平。闭塞后10分钟（治疗前），未治疗犬（0.11±0.03毫升/分钟/克；0.31±0.05）和治疗犬（0.14±0.02毫升/分钟/克；0.29±0.03）的侧支血流值和缺血区心内膜/心外膜血流比值相当。在未治疗犬中，5小时内侧支血流未发生变化；5小时时心内膜/心外膜血流比值降低（0.21±0.05，P<0.05）。相比之下，在治疗犬中，70分钟时侧支血流和心内膜/心外膜血流比值增加（0.27±0.04毫升/分钟/克，P<0.05；0.53±0.10，P<0.05）。最重要的是，尽管闭塞70分钟后停止治疗，但闭塞5小时后侧支血流仍保持升高（0.26±0.03毫升/分钟/克，P<0.05）。因此，未治疗犬在闭塞5小时内侧支血流无变化，但硝酸甘油和甲氧明的短期治疗导致侧支血流持续增加。这些发现可能是由于硝酸甘油和甲氧明刺激了缺血后内源性侧支功能增加的自发速率。或者，硝酸甘油和甲氧明可能维持细胞活力直至侧支血管自发形成。
