Epinephrine, phenylephrine, and methoxamine induce infiltrative anesthesia via al-adrenoceptors in rats  

作　　者：Ja-ping SHIEH Chin-chen CHU Jhi-joung WANG Mao-tsun LIN 

机构地区：[1]Department of Anesthesiology and Chi Mei Medical Center, Tainan, Taiwan, China [2]Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan, China

出　　处：《Acta Pharmacologica Sinica》2009年第9期1227-1236,共10页中国药理学报（英文版）

摘　　要：Aim： To assess whether epinephrine, phenylephrine, and methoxamine act via certain subtypes of adrenoceptors to exert their local anesthetic activity. Methods： We investigated cutaneous anesthesia from adrenoceptor agonists and/or antagonists in conscious, unanesthetized Sprague-Dawley male rats （weight 200-250 g）. Cutaneous anesthesia was evidenced by a block of the cutaneous trunci muscle reflex, which is characterized by reflex movement of the skin over the back produced by twitches of lateral thoracispinal muscles in response to local dorsal cutaneous noxious pinprick. Results： Local infiltration of epinephrine, L-phenylephrine, or methoxamine alone induces cutaneous anesthesia in rats in a dosedependent way. Epinephrine is found to be 19 and 29 times more potent than those of methoxamine and L-phenylephrine, respectively. The cutaneous anesthesia induced by epinephrine, phenylephrine, or methoxamine can be significantly reduced by α1-adrenoceptor antagonists （eg, prazosin）, α1, α2-adrenoceptor antagonist, α1A-adrenoceptor antagonist （eg, 5-methylurapdil）, α1B^- adrenoceptor antagonist （eg, chloroethylclonidine）, or α10-adrenoceptor antagonist （eg, BMY7873）. Conclusion： Our results indicate that epinephrine, phenylephrine and methoxamine all act mainly via mixed subtypes of α2-adrenoceptors to induce cutaneous anesthesia in the rat.Aim： To assess whether epinephrine, phenylephrine, and methoxamine act via certain subtypes of adrenoceptors to exert their local anesthetic activity. Methods： We investigated cutaneous anesthesia from adrenoceptor agonists and/or antagonists in conscious, unanesthetized Sprague-Dawley male rats （weight 200-250 g）. Cutaneous anesthesia was evidenced by a block of the cutaneous trunci muscle reflex, which is characterized by reflex movement of the skin over the back produced by twitches of lateral thoracispinal muscles in response to local dorsal cutaneous noxious pinprick. Results： Local infiltration of epinephrine, L-phenylephrine, or methoxamine alone induces cutaneous anesthesia in rats in a dosedependent way. Epinephrine is found to be 19 and 29 times more potent than those of methoxamine and L-phenylephrine, respectively. The cutaneous anesthesia induced by epinephrine, phenylephrine, or methoxamine can be significantly reduced by α1-adrenoceptor antagonists （eg, prazosin）, α1, α2-adrenoceptor antagonist, α1A-adrenoceptor antagonist （eg, 5-methylurapdil）, α1B^- adrenoceptor antagonist （eg, chloroethylclonidine）, or α10-adrenoceptor antagonist （eg, BMY7873）. Conclusion： Our results indicate that epinephrine, phenylephrine and methoxamine all act mainly via mixed subtypes of α2-adrenoceptors to induce cutaneous anesthesia in the rat.

关 键 词：ANESTHESIA EPINEPHRINE vasoconstriction PHENYLEPHRINE METHOXAMINE 

分 类 号：S813.22[农业科学—畜牧学] Q132.1[农业科学—畜牧兽医]