Hung Ching-Hsia, Chiu Chong-Chi, Liu Kuo-Sheng, Wang Jhi-Joung, Chen Yu-Wen
Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Department of General Surgery, Chi Mei Medical Center, Tainan and Liouying, Taiwan; Department of Electrical Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan.
Neurosci Lett. 2016 Mar 11;616:70-4. doi: 10.1016/j.neulet.2016.01.054. Epub 2016 Jan 29.
Clonidine prolongs duration of analgesia when used as an adjunct to local anesthetics for infiltrative cutaneous analgesia, and propranolol produces local anesthesia. The purpose of the experiment was to evaluate clonidine as an adjuvant for propranolol on the quality and duration of cutaneous analgesia. A rat model of cutaneous trunci muscle reflex (CTMR) in response to local skin pinprick was employed to evaluate the cutaneous analgesic effect of propranolol combined with clonidine. The long-lasting local anesthetic bupivacaine was used as control. Cutaneous analgesia elicited by propranolol and bupivacaine was dose-dependent, and both propranolol (9.0μmol) and bupivacaine (1.8μmol) produced 100% nociceptive blockade. On an 50% effective dose (ED50) basis, the relative potency was bupivacaine [0.48 (0.42-0.55) μmol] greater than propranolol [2.27 (1.98-2.54) μmol] (p<0.01). Subcutaneous saline and clonidine (0.12μmol) did not produce cutaneous analgesia. The mixture of an ineffective-dose clonidine (0.12μmol) and a drug (propranolol or bupivacaine) at ED50 or ED95 increased the potency and extended the duration at producing cutaneous analgesia. The resulting data demonstrated that propranolol is less potent than bupivacaine as an infiltrative anesthetic. Clonidine as an adjuvant for propranolol or bupivacaine has a significant peripheral action in increasing the depth and duration of action on infiltrative cutaneous analgesia.
可乐定用作局部麻醉药辅助剂用于浸润性皮肤镇痛时可延长镇痛持续时间，而普萘洛尔可产生局部麻醉作用。本实验的目的是评估可乐定作为普萘洛尔辅助剂对皮肤镇痛质量和持续时间的影响。采用大鼠躯干皮肤反射（CTMR）模型对局部皮肤针刺反应进行评估，以评价普萘洛尔联合可乐定的皮肤镇痛效果。长效局部麻醉药布比卡因用作对照。普萘洛尔和布比卡因引起的皮肤镇痛呈剂量依赖性，普萘洛尔（9.0μmol）和布比卡因（1.8μmol）均可产生100%的伤害性阻断。以半数有效剂量（ED50）为基础，布比卡因[0.48（0.42 - 0.55）μmol]的相对效价比普萘洛尔[2.27（1.98 - 2.54）μmol]高（p<0.01）。皮下注射生理盐水和可乐定（0.12μmol）未产生皮肤镇痛作用。无效剂量的可乐定（0.12μmol）与ED50或ED95剂量的药物（普萘洛尔或布比卡因）混合使用，可提高产生皮肤镇痛的效力并延长其持续时间。所得数据表明，作为浸润性麻醉药，普萘洛尔的效力低于布比卡因。可乐定作为普萘洛尔或布比卡因的辅助剂，在增强浸润性皮肤镇痛的深度和作用持续时间方面具有显著的外周作用。
