In vitro and in vivo characterization of opioid activities of C-terminal esterified endomorphin-2 analogs |
| |
Authors: | Chang-lin Wang Chao Guo Ying Zhou Rui Wang |
| |
Institution: | aState Key Laboratory of Chinese Medicine and Molecular Pharmacology, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China;bKey Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Biochemistry and Molecular Biology, School of Basic Medical Sciences, State Key Laboratory of Applied Organic Chemistry, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China |
| |
Abstract: | Previously, we have synthesized a series of endomorphin-2 (EM-2) analogs by the substitution of C-terminal amide group. In the present study, to further our knowledge of the influence of C-terminal esterified modification on the pharmacological activities, we investigated the in vitro and in vivo opioid activities of C-terminal esterified EM-2 analogs 1–3. Our results showed that the ED50 values on contractions of the longitudinal muscle of distal colon induced by analogs 1–3 were about 1.5-fold higher, 2- and 8-fold lower than EM-2, respectively. In addition, intravenous (i.v.) injections of analogs 1 and 2 dose-dependently decreased the system arterial pressure (SAP) and heart rate (HR) in anesthetized rats, but the degree of the hypotension and bradycardia was significantly smaller relative to the parent. Moreover, analog 3 was almost ineffective. Nevertheless, all these analogs produced potent antinociception in the tail-flick test after intracerebroventricular (i.c.v.) injection, and this antinociception was inhibited by naloxone, indicating an opioid mechanism. In summary, these results gave the evidence that the conversion of C-terminal amide to esterified modification may play an important role in the regulation of opioid affinities and pharmacological activities. |
| |
Keywords: | Endomorphin-2 C-terminal esterified analogs Colonic contraction Cardiovascular response Antinociception |
本文献已被 ScienceDirect 等数据库收录! |
|