PERIPHERAL AND CARDIAC ADRENERGIC RESPONSE TO COLD STRESS

外周和心脏肾上腺素对冷应激的反应

• 批准号: 6245411
• 负责人: STEVEN FRANK
• 金额: $ 2.23万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-03-05 至 1997-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6245411
• 关键词: age difference; alpha adrenergic receptor; alpha antiadrenergic agent; body temperature regulation; cardiovascular function; clinical research; human old age (65+); human subject; induced hypothermia; oxygen consumption; peripheral blood vessel; thermogenesis; young adult human (21-34)

Small changes in core temperature have been shown to trigger a significant adrenergic response which may be the etiology of cold- induced myocardial ischemia. However, previous studies investigating this adrenergic response have been performed in young individuals, and the effects of age are unknown. In addition, no studies have been performed in humans to assess methods to block the potentially harmful effects of hypothermia. We designed a study to compare the adrenergic response to hypothermia in young vs. old human volunteers, and the use of alpha-adrenoceptor antagonists to block this response. The study was completed in June of 1996, The data show that the elderly are less able to maintain body temperature during cold challenge. This is due to a desensitization of the alpha receptor and the inability to vasocontrict in the presence of normal or even increased norepinephrine release. Shivering and total body oxygen consumption were also impaired in the elderly as demonstrated by reduced gain of this response. The elderly are more sensitive to the thermoregulatory effects of alpha blockade compared to the young. Alpha-antagonists selectively impair the vasoconstriction response to core hypothermia, but not the shivering response. This selective inhibition could be clinically useful since the adverse cardiovascular effects of hypothermia appear to be adrenergically mediated.

地核温度的微小变化已被证明会触发 显著的肾上腺素能反应，这可能是感冒的原因 诱导心肌缺血。然而，之前的研究调查了 这种肾上腺素能反应已经在年轻人身上进行过，而且 年龄的影响是未知的。此外，目前还没有任何研究 在人类身上进行，以评估阻止潜在有害物质的方法 体温过低的影响。我们设计了一项研究来比较肾上腺素能 年轻人和老年人志愿者对低温的反应，以及使用 α-肾上腺素能受体拮抗剂来阻断这种反应。 这项研究于1996年6月完成，数据显示，老年人 在寒冷的挑战中保持体温的能力较差。这 是由于阿尔法受体的脱敏和无法 去甲肾上腺素正常或升高时的血管收缩 放手。颤抖和全身耗氧量也受到了损害。 在老年人中，这一反应的收益减少就证明了这一点。 老年人对阿尔法的体温调节作用更敏感 与年轻人相比，封锁。阿尔法-拮抗剂选择性地损害 血管收缩对核心低温的反应，但不是颤抖 回应。这种选择性抑制可能在临床上有用，因为 低体温对心血管的不良影响似乎是 以肾上腺素为媒介。