兔耳和股动脉的冷却及对肾上腺素能受体激动剂的反应：内皮的作用

Cooling and response to adrenoceptor agonists of rabbit ear and femoral artery: role of the endothelium.

作者信息

García-Villalón A L, Monge L, Montoya J J, García J L, Fernández N, Gómez B, Diéguez G

机构信息

Departamento de Fisiologia, Facultad de Medicina, Universidad Autónoma, Madrid, Spain.

出版信息

Br J Pharmacol. 1992 Jul;106(3):727-32. doi: 10.1111/j.1476-5381.1992.tb14401.x.

DOI:10.1111/j.1476-5381.1992.tb14401.x

PMID:1354546

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1907563/

Abstract

The effects of cooling on the response of the rabbit central ear (cutaneous) and femoral (non-cutaneous) arteries to stimulation of adrenoceptors and the role of the endothelium in these effects, were studied in 2 mm long cylindrical segments. 2. Concentration-response curves for noradrenaline (10(-9)-3 x 10(-4) M), phenylephrine (alpha 1-adrenoceptor agonist, 10(-9)-3 x 10(-4) M) and B-HT 920 (alpha 2-adrenoceptor agonist, 10(-7)-10(-3) M) were recorded isometrically in arteries with and without endothelium at 37 degrees C and at 24 degrees C (cooling). To analyze further the endothelial mechanisms in the responses to adrenoceptor stimulation during cooling, the effects of the adrenoceptor agonists on ear arteries in the presence of NG-nitro-L-arginine methyl esther (L-NAME) (10(-5) M) were also determined. 3. In every condition tested, the three adrenoceptor agonists produced a concentration-dependent arterial contraction and the order of potency in ear and femoral arteries was noradrenaline greater than or equal to phenylephrine greater than B-HT 920. The response of ear and femoral arteries to phenylephrine or B-HT 920 was blocked by prazosin (10(-6) M). Yohimbine (10(-6) M) decreased slightly the response of ear arteries and increased that of femoral arteries to B-HT 920. 4. The sensitivity of both ear and femoral arteries to the three adrenoceptor agonists was significantly lower at 24 degrees C than at 37 degrees C. 5. In ear arteries, endothelium removal or treatment with L-NAME did not influence the response at 37 degrees C, but did increase it during cooling to adrenoceptor stimulation.In femoral arteries, endothelium removal increased the sensitivity to noradrenaline and, especially, to B-HT 920 at 37 degrees C, but did not affect the response at 24 degrees C.6. The results suggest that: (a) rabbit ear and femoral arteries are equipped mainly with alpha 1-adrenoceptors;(b) at 37 degrees C, the contraction of the ear artery to adrenoceptor agonists is mostly endothelium-independent, and in the femoral artery the contraction to alpha 2-adrenoceptor activation is endothelium-dependent; (c) cooling inhibits the contraction to adrenoceptor agonists in both ear and femoral arteries: in the ear artery probably by increasing the availability of endothelial nitric oxide, but in the femoral artery by depressing the sensitivity of alpha-adrenoceptors in the smooth musculature.7. The results suggest that the endothelium may modulate the adrenoceptor response of cutaneous arteries during changes in temperature.

摘要

在2毫米长的圆柱形节段中，研究了冷却对兔中耳（皮肤）和股动脉（非皮肤）对肾上腺素能受体刺激的反应的影响，以及内皮在这些影响中的作用。2. 在37℃和24℃（冷却）条件下，对等长记录有内皮和无内皮的动脉中去甲肾上腺素（10⁻⁹ - 3×10⁻⁴ M）、苯肾上腺素（α₁肾上腺素能受体激动剂，10⁻⁹ - 3×10⁻⁴ M）和B-HT 920（α₂肾上腺素能受体激动剂，10⁻⁷ - 10⁻³ M）的浓度-反应曲线。为了进一步分析冷却期间对肾上腺素能受体刺激反应中的内皮机制，还测定了在存在NG-硝基-L-精氨酸甲酯（L-NAME）（10⁻⁵ M）的情况下肾上腺素能受体激动剂对耳动脉的影响。3. 在每个测试条件下，三种肾上腺素能受体激动剂均产生浓度依赖性的动脉收缩，且在耳动脉和股动脉中的效力顺序为去甲肾上腺素≥苯肾上腺素＞B-HT 920。耳动脉和股动脉对苯肾上腺素或B-HT 920的反应被哌唑嗪（10⁻⁶ M）阻断。育亨宾（10⁻⁶ M）略微降低了耳动脉对B-HT 920的反应，并增加了股动脉对B-HT 920的反应。4. 耳动脉和股动脉对三种肾上腺素能受体激动剂的敏感性在24℃时均显著低于37℃时。5. 在耳动脉中，去除内皮或用L-NAME处理在37℃时不影响反应，但在冷却期间对肾上腺素能受体刺激的反应增加。在股动脉中，去除内皮增加了对去甲肾上腺素的敏感性，尤其是在37℃时对B-HT 920的敏感性，但在24℃时不影响反应。6. 结果表明：（a）兔耳动脉和股动脉主要配备α₁肾上腺素能受体；（b）在37℃时，耳动脉对肾上腺素能受体激动剂的收缩大多不依赖内皮，而在股动脉中，对α₂肾上腺素能受体激活的收缩依赖内皮；（c）冷却抑制耳动脉和股动脉对肾上腺素能受体激动剂的收缩：在耳动脉中可能是通过增加内皮一氧化氮的可用性，但在股动脉中是通过降低平滑肌中α肾上腺素能受体的敏感性。7. 结果表明，在内皮温度变化期间，内皮可能调节皮肤动脉的肾上腺素能受体反应。