J Li1, X Li, G Pei, B Y Qin. 1. Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, China.
Abstract
AIM: To study the effect of agmatine on pain and morphine analgesia. METHODS: The effect of agmatine on pain was observed in mouse heat radiant tail-flick test, mouse acetic acid writhing test, and rat 4% saline test. Its enhancing effect on analgesia of morphine and clonidine was assessed in rat and mouse heat radiant tail-flick tests. RESULTS: Agmatine did not significantly prolong tail-flick latency of mice, but reduced the number of acetic acid-induced writhing of mice and inhibited writhing responses to saline completely. It potentiated the analgesic effects of morphine and clonidine in dose-dependent manner and decreased the analgesic ED50 of morphine and clonidine by more than 75% in mouse heat radiant tail-flick test. These effects of agmatine were antagonized by idazoxan. CONCLUSION: Agmatine has weak analgesic effects and potentiates morphine and clonidine analgesia by activation of imidazoline receptors.
AIM: To study the effect of agmatine on pain and morphine analgesia. METHODS: The effect of agmatine on pain was observed in mouse heat radiant tail-flick test, mouseacetic acid writhing test, and rat 4% saline test. Its enhancing effect on analgesia of morphine and clonidine was assessed in rat and mouse heat radiant tail-flick tests. RESULTS:Agmatine did not significantly prolong tail-flick latency of mice, but reduced the number of acetic acid-induced writhing of mice and inhibited writhing responses to saline completely. It potentiated the analgesic effects of morphine and clonidine in dose-dependent manner and decreased the analgesic ED50 of morphine and clonidine by more than 75% in mouse heat radiant tail-flick test. These effects of agmatine were antagonized by idazoxan. CONCLUSION:Agmatine has weak analgesic effects and potentiates morphine and clonidine analgesia by activation of imidazoline receptors.