Dexmedetomidine enhances the local anesthetic action of lidocaine via an α-2A adrenoceptor
Dexmedetomidine enhances the local anesthetic action of lidocaine via an α-2A adrenoceptor
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DOI：
10.1213/ane.0b013e318176be73
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发表时间：
2008-07-01
影响因子：
5.7
通讯作者：
Miyawaki, Takuya
中科院分区：
文献类型：
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作者：
Yoshitomi, Tatsushi;Kohjitani, Atsushi;Miyawaki, Takuya
背景：可乐定是一种α -2肾上腺素能受体激动剂，在中枢和外周阻滞中都是一种常见的辅助药物。右美托咪定是一种选择性更强的α -2肾上腺素能受体激动剂，也可增强中枢神经阻滞。然而，其外围效应尚未完全阐明。因此，我们评估了右美托咪定和其他α -2肾上腺素能受体激动剂对利locaine外周局麻作用的影响，并探讨了其机制。方法：在雄性豚鼠背部静脉注射α -2肾上腺素能受体激动剂，包括右美托咪定、可乐定、氧美唑啉等。每5分钟进行6个针刺试验，直至注射后60分钟。将针刺在60分钟内未引起反应的次数相加，作为局部麻醉程度的麻醉评分。与组内控制值的差异使用方差分析和事后邓尼特检验进行分析。此外，我们评估了双咪定、托托咪定对育亨宾（α - 2a、2B和2C肾上腺素受体拮抗剂）或吡唑嗪（α -1、α -213和2C肾上腺素受体拮抗剂）的拮抗作用，并采用双向方差分析进行了分析。结果：所有α -2肾上腺素能受体激动剂均能增强利多卡因的局部麻醉程度，且呈剂量依赖性。此外，育亨宾抑制右美托咪定的作用，而吡唑嗪没有。结论：α -2肾上腺素能受体激动剂增强利多卡因的局部麻醉作用，提示右美托咪定通过α - 2a肾上腺素受体起作用。
BACKGROUND: Clonidine, an alpha-2 adrenoceptor agonist, is a common adjunct in both central and peripheral blocks. Dexmedetomidine, a more selective alpha-2 adrenoceptor agonist, is also known to enhance central neural blockades. Its peripheral effect, however, has not been fully elucidated. Thus, we evaluated the effect of dexmedetomidine and other alpha-2 adrenoceptor agonists on the local anesthetic action of liclocaine at the periphery and explored the mechanism involved.METHODS: alpha-2 Adrenoceptor agonists, including dexmedetomidine, clonidine, and oxymetazoline, combined with liclocaine were intracutaneously injected into the back of male guinea pigs. The test of six pinpricks was applied every 5 min until 60 min after the injection. The number of times which the prick failed to elicit a response during the 60-min period was added and the sum served as an anesthetic score indicating the degree of local anesthesia. Differences from the control value within the group were analyzed using an analysis of variance followed by a post hoc Dunnett's test. Furthermore, we evaluated the antagonism of the effect of dexme-, detomidine by yohimbine, an alpha-2A, 2B, and 2C adrenoceptor antagonist, or prazosin, an alpha-1, alpha-213, and 2C adrenoceptor antagonist, analyzed using a two-way analysis of variance.RESULTS: All alpha-2 adrenoceptor agonists enhanced the degree of local anesthesia of lidocaine in a dose-dependent manner. Furthermore, yohimbine inhibited the effect of dexmedetomidine, whereas prazosin did not.CONCLUSION: We demonstrated that alpha-2 adrenoceptor agonists enhanced the local anesthetic action of lidocaine, and suggest that dexmedetomidine acts via alpha-2A adrenoceptors.