Miller V M, Miller W L, South F E
Am J Physiol. 1986 Jan;250(1 Pt 2):R77-82. doi: 10.1152/ajpregu.1986.250.1.R77.
To determine the effects of season, acclimation state, and hibernation on the reactivity of vascular smooth muscle from a hibernant species, strips of thoracic aorta, renal and femoral arteries, and portal vein obtained from adult woodchucks, Marmota monax, were suspended for isometric tension measurements in physiological salt solution. These blood vessels exhibited no seasonal variation in resting tension, connective tissue content, or maximum tension developed to norepinephrine. However, the concentration-response curves to norepinephrine in both aortic and portal vein strips from animals tested in May and June were shifted to the left of those from animals tested in either August or November through February. This increased sensitivity to the catecholamine was seen also in renal vessels from hibernating compared with nonhibernating animals. Decreasing organ bath temperature from 37 to 28 degrees C increased tension developed in response to norepinephrine in aortic and renal strips, whereas that of the femoral artery was unchanged. With further cooling to 17 degrees C, the responses to norepinephrine in aortic and renal strips were similar to the responses at 37 degrees C. The contraction developed to 40 mM KCl was diminished in all tissues at 28 degrees C. Blockade of beta-adrenergic receptors did not augment the response to norepinephrine at 37 degrees C. Contractions of the woodchuck aorta in calcium-free medium were sustained longer than comparable tissue obtained from a rabbit. These data suggest that receptor-mediated processes are modulated in hibernating animals. This modulation varies among vascular beds and may act to maintain or divert perfusion of the tissue through entry, during, and arousal from hibernation.
为了确定季节、适应状态和冬眠对冬眠动物血管平滑肌反应性的影响，从成年土拨鼠（Marmota monax）获取胸主动脉、肾动脉、股动脉和门静脉条带，将其悬挂于生理盐溶液中进行等长张力测量。这些血管在静息张力、结缔组织含量或对去甲肾上腺素产生的最大张力方面未表现出季节性变化。然而，5月和6月测试动物的主动脉和门静脉条带对去甲肾上腺素的浓度 - 反应曲线相较于8月或11月至2月测试动物的曲线向左偏移。与非冬眠动物相比，冬眠动物的肾血管对儿茶酚胺的敏感性也增加。将器官浴温度从37℃降至28℃会增加主动脉和肾条带对去甲肾上腺素产生的张力，而股动脉的张力则未改变。进一步冷却至17℃时，主动脉和肾条带对去甲肾上腺素的反应与37℃时相似。在28℃时，所有组织对40 mM KCl产生的收缩均减弱。β - 肾上腺素能受体的阻断在37℃时并未增强对去甲肾上腺素的反应。在无钙培养基中，土拨鼠主动脉的收缩持续时间比从兔子获取的类似组织更长。这些数据表明冬眠动物中受体介导的过程受到调节。这种调节在不同血管床之间存在差异，并且可能在冬眠进入期、冬眠期和苏醒期通过维持或改变组织灌注起作用。
