Miyazawa K, Hashimoto H, Nakashima M
Department of Pharmacology, Hamamatsu University School of Medicine, Shizuoka, Japan.
Arch Int Pharmacodyn Ther. 1989 Jan-Feb;297:120-32.
The effect of thyroid hormones on vascular responses to various agents was examined in the coronary vascular bed perfused by the Langendorff's method at a fixed flow rate with Krebs-Henseleit solution in isolated rat hearts. In this study, ventricular fibrillation was induced by electrical stimulation to avoid secondary influences derived from alteration of ventricular contractility by agents. Vasodilator responses of coronary arteries to isoproterenol and methacholine were significantly enhanced in hyperthyroid preparations compared with those observed in euthyroid ones, though vasodilator responses to histamine and adenosine were not affected by hyperthyroidism. Vasoconstrictor response to 5-hydroxytryptamine (5-HT) was significantly potentiated by hyperthyroidism though that to balium chloride was not affected. So, these alterations in vascular responses by hyperthyroidism are assumed not to be nonspecific but to be mediator-specific events. As vasoconstriction in coronary arteries lowers oxygen supply to myocardium, enhanced vasoconstrictivity of coronary arteries to 5-HT by hyperthyroidism may be responsible for an exacerbation of heart disease in the case of patients having agglutinative thrombus, which should be a source of 5-HT, in their coronary arteries.
采用Langendorff法，以Krebs-Henseleit溶液在固定流速下灌注离体大鼠心脏的冠状动脉床，研究甲状腺激素对血管对各种药物反应的影响。在本研究中，通过电刺激诱发心室颤动，以避免药物改变心室收缩力产生的继发影响。与正常甲状腺状态的制剂相比，甲状腺功能亢进的制剂中冠状动脉对异丙肾上腺素和乙酰甲胆碱的血管舒张反应显著增强，而对组胺和腺苷的血管舒张反应不受甲状腺功能亢进的影响。甲状腺功能亢进显著增强了对5-羟色胺（5-HT）的血管收缩反应，但对氯化钡的反应不受影响。因此，甲状腺功能亢进引起的这些血管反应改变被认为不是非特异性的，而是介质特异性事件。由于冠状动脉血管收缩会降低心肌的氧气供应，甲状腺功能亢进导致冠状动脉对5-HT的血管收缩性增强，可能是冠状动脉中有凝集性血栓（5-HT的来源）的患者心脏病加重的原因。
