Department Of Physical Education, Honan College, 72 Nakayama, 399-0424, Tatsuno, Nagano.
Environ Health Prev Med. 1998 Jul;3(2):78-82. doi: 10.1007/BF02931788.
We investigated the responses of thoracic aortae to adrenergic contraction and endothelium-dependent relaxation following chronic exposure to cold in rats. Two groups (CA, cold-acclimated for 12 weeks at 5 °C; WA, warm-acclimated for 12 weeks at 24 °C) of 10 male Sprague-Dawley rats were used. After anesthesia, the thoracic aortae (4 mm long) were isolated and the vascular tension was measured with a force transducer. The dose-response relations for aortic responses to norepinephrine (NE), phenylephrine (PE) and acetylcholine (Ach) were determined and compared between the CA and the WA groups. In the CA rats, the thoracic aortae became more sensitive to Ach-induced vasorelaxation. The vascular sensitivities to NE- or PE-induced contraction in the thoracic aortae were lowered. Chronic exposure to cold decreased NE- and PE-induced vasoconstrictive responses and increased Achinduced vasorelaxative response of the isolated thoracic aortae, which were suggested to be due to enhanced release of NE-induced endothelium-derived relaxing factor by up-regulating endothelial α1-adrenoceptors.
我们研究了慢性暴露于寒冷环境后大鼠胸主动脉对肾上腺素能收缩和内皮依赖性舒张的反应。使用了两组(CA,在 5°C 下适应寒冷 12 周;WA,在 24°C 下适应温暖 12 周)的 10 只雄性 Sprague-Dawley 大鼠。麻醉后,分离胸主动脉(4mm 长),并用力传感器测量血管张力。确定了 CA 和 WA 组大鼠胸主动脉对去甲肾上腺素(NE)、苯肾上腺素(PE)和乙酰胆碱(Ach)的反应的剂量-反应关系,并进行了比较。在 CA 大鼠中,胸主动脉对 Ach 诱导的血管舒张的敏感性增加。胸主动脉对 NE 或 PE 诱导的收缩的血管敏感性降低。慢性暴露于寒冷会降低 NE 和 PE 诱导的血管收缩反应,并增加 Ach 诱导的分离胸主动脉的血管舒张反应,这可能是由于通过上调内皮 α1-肾上腺素受体增强了 NE 诱导的内皮衍生松弛因子的释放。