Subcutaneous L-tyrosine elicits cutaneous analgesia in response to local skin pinprick in rats

doi:10.1016/j.ejphar.2015.09.010

CNU IR > Pharmacy and Science > Dept. of Pharmacy > Periodical Articles > Item 310902800/29749

Please use this identifier to cite or link to this item: https://ir.cnu.edu.tw/handle/310902800/29749

Title:	Subcutaneous L-tyrosine elicits cutaneous analgesia in response to local skin pinprick in rats
Authors:	Hung, Ching-Hsia Chiu, Chong-Chi Liu, Kuo-Sheng Chen, Yu-Wen Wang, Jhi-Joung
Contributors:	藥學系
Keywords:	L-tyrosine Lidocaine Cutaneous analgesia Lsobologram
Date:	2015-10
Issue Date:	2016-04-19 19:06:49 (UTC+8)
Publisher:	Elsevier Science Bv
Abstract:	The purpose of the study was to estimate the ability of L-tyrosine to induce cutaneous analgesia and to investigate the interaction between L-tyrosine and the local anesthetic lidocaine. After subcutaneously injecting the rats with L-tyrosine and lidocaine in a dose-dependent manner, cutaneous analgesia (by blocking the cutaneous trunci muscle reflex-CTMR) was evaluated in response to the local pinprick. The drug-drug interaction was analyzed by using an isobolographic method. We showed that both L-tyrosine and lidocaine produced dose-dependent cutaneous analgesia. On the 50% effective dose (ED50) basis, the rank of drug potency was lidocaine (5.09 [4.88-538] mu mol) > L-tyrosine (39.1 [36.5-41.8] mu mol) (P <0.05). At the equipotent doses (ED25, ED50, and ED75), the duration of cutaneous analgesia caused by L-tyrosine lasted longer than that caused by lidocaine (P <0.01). Lidocaine co-administered with L-tyrosine exhibited an additive effect on infiltrative cutaneous analgesia. Our pre-clinical study demonstrated that L-tyrosine elicits the local/cutaneous analgesia, and the interaction between L-tyrosine and lidocaine is additive. L-tyrosine has a lower potency but much greater duration of cutaneous analgesia than lidocaine. Adding L-tyrosine to lidocaine preparations showed greater duration of cutaneous analgesia compared with lidocaine alone. (C) 2015 Elsevier B.V. All rights reserved.
Relation:	European Journal of Pharmacology, v.765,pp.457-462
Appears in Collections:	[Dept. of Pharmacy] Periodical Articles

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