dxy

[每周一问]NO.17-Alpha 2 Adrenoceptor Agonists
Author's Note: This week we will be discussing the pharmacology and clinical application of alpha 2 adrenoceptor agonists.
1.  What are alpha 2 adrenoceptor agonists?
2.  How are alpha 2 adrenoceptor agonists classified?
α-2肾上腺素受体激动剂
本周我们讨论α-2肾上腺素受体激动剂的药理学和临床应用
1.什么是α-2肾上腺素受体激动剂？
2. α-2肾上腺素受体激动剂如何分类？

参考答案
1.什么是α-2肾上腺素受体激动剂？
α-2肾上腺素受体激动剂（α-2激动剂）主要是作为原发性高血压的治疗使用。然而，这些α-2激动剂最近被研究了其它的特性，包括镇静、镇痛、减少战栗等，因此，这些潜在的作用对麻醉状态下的手术病人是非常重要的。
α-2激动剂最初与α-1激动剂是通过突触前的作用位点而区分[1]。然而，大量研究发现有大量的突触后和突触外的位点存在[2]。而且，α-2肾上腺素受体发现存在于不同的组织，包括肾脏、血小板、膀胱、肠壁、血管壁、中枢及外周神经系统[3]。这些受体的兴奋可以调整大量关于失眠、全身压力、心率、体温调节、肌紧张和创伤性感觉的机制。
2. α-2肾上腺素受体激动剂如何分类？
答案2见下图
 

英文答案
What are alpha 2 adrenoceptor agonists?
Alpha 2 adrenoceptor agonists (alpha 2 agonists) are known principally for their treatment of essential hypertension. However, these alpha 2 agonists are currently being investigated for other properties, including sedation, analgesia, and decreased shivering, and consequently, their potential contribution to the surgical patient undergoing anesthesia could be important .
Alpha 2 agonists were initially distinguished from their alpha 1 cousins by their presynaptic position (1). However, further investigation discovered a number of postsynaptic and extrasynaptic locations (2). Moreover, alpha 2 adrenoceptors have been found in a number of distinct tissues, including kidney, platelets, bladder, bowel walls, vascular walls, and the central and peripheral nervous systems (3). Stimulation of these receptors is responsible for modulating the control of a number of mechanisms of vigilance, systemic pressure, heart rate, thermoregulation, muscular tone, and nociceptive perception.
How are alpha 2 adrenoceptor agonists classified?
Alpha 2 agonists have been categorized into three main classes, based in part on their chemical structures (4):

References:
1.  Van Zwieten PA. Central and peripheral alpha-adrenoceptors. Pharmacological aspects and clinical potential. Adv Drug Res 1979;13:221-253.
2.  Kingery WS, Guo TZ, Davies MF et al. The alpha(2A) adrenoceptor and the sympathetic postganglionic neuron contribute to the development of neuropathic heat hyperalgesia in mice. Pain 2000 Apr;85(3):345-58.
3.  DeBels D, Coriat P. Alpha 2 adrenoceptor agonists: An increasing role in modern anesthesia. Problems in Anesthesia 2000;12:65-72.
4.  Bonnet F, Darmon PL. Interferences entre les medicaments cardio-vasculaire et l'anesthesie, IV: Les agonistes alpha-2 adrenergiques. In: Coriat P, ed. Les Contraintes Circulatoire et le Risque Cardiaque de L'Anesthesie. Paris: Arnette, 2000:291-305.
Site Editor: Stephen B. Corn, M.D. and B. Scott Segal, M.D.
Department of Anesthesia, Harvard Medical School
Founders and Editors-in-Chief: Stephen B. Corn, M.D. and B. Scott Segal, M.D.
Department of Anesthesiology, Perioperative and Pain Medicine, Harvard Medical School