Effects of vasoconstrictor agents on flow rate of isolated epicardial coronary artery of humans with various degrees of atherosclerosis and of young pigs.
Constriction of epicardial coronary arteries induces severe flow reduction causing myocardial ischaemia in patients with vasospastic angina. Whether such constriction is inherent in coronary arteries in general was determined by perfusing isolated epicardial coronary segments of humans and pigs at a constant perfusion pressure. Mean flow reduction after perfusion with potassium chloride (60 mmol.litre-1), acetylcholine (10(-9)-10(-5) mol.litre-1), and histamine (10(-8)-10(-4) mol.litre-1) was not different between humans and pigs. Prostaglandin F2 alpha (PGF2 alpha; 3 X 10(-6) mol.litre-1) decreased the flow more substantially in humans (by 74(9)%) than in pigs (by 6(1)%) (p less than 0.01). A pronounced flow reduction to 0 ml.min-1 was observed in eight of 17 human coronary arteries after potassium chloride, histamine, or PGF2 alpha perfusion but in none of the pigs. Histological examination of the coronary arteries showed no atherosclerotic lesions in the pigs but various lesions in humans, ranging from intimal thickening to 96% luminal stenosis in cross sectional area. Flow reduction after PGF2 alpha was significantly greater in human coronary arteries with stenoses greater than 50% (94(4)%) than in those with stenoses less than 25% (55(14)%) (p less than 0.05). Complete cessation of flow was observed more often in the stenotic arteries (greater than 50% stenosis) than in others (p less than 0.05). A substantial reduction in flow, which may cause myocardial ischaemia in vivo, was not seen in normal pig coronary arteries even after strong vasoconstrictor stimuli but was present in human coronary arteries with atherosclerosis.
Sakaino
N
N
Department of Pharmacology, Kumamoto University Medical School, Japan.
Araki
H
H
Nishi
K
K
Kimura
T
T
Yasue
H
H
D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D003324:Coronary Artery Disease / Q000473:pathology / Q000503:physiopathology*; D003331:Coronary Vessels / Q000187:drug effects* / Q000473:pathology; D015237:Dinoprost / Q000494:pharmacology; D005260:Female; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D011189:Potassium Chloride / Q000494:pharmacology; D013552:Swine; D014655:Vascular Resistance / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D011189:Potassium Chloride; D006632:Histamine; D015237:Dinoprost; D000109:Acetylcholine