The peeled root,stem or twig of Syringa pinnatifolia is a representative Mongolian folk medicine with the effects of antidepression and pain relief. It has been used for the treatments of heart tingling,heart palpitations,upset,insomnia and other symptoms. Inspired by Mongolian medical theory and clinical practices,this study evaluated the analgesic effect of S. pinnatifolia ethanol extract( T) through three analgesic models including acetic acid writhing test,formalin test,and hot plate test,and the sedative effect of T was evaluated by locomotor activity and synergistic sleeping experiments,and furthermore the effects of T on the GABAergic nervous system were investigated by ELISA,immunohistochemistry,Western blot,and PCR methods. The results showed that T can significantly reduce the number of writhing,the time of paw licking and extend the thermal threshold of mice,suggesting the analgesic effect of T.T also can indicate its sedative effect by reducing the number of activities,decreasing latency of sleeping and extending sleeping time of mice. ELISA results showed that T can increase the content of GABA/Glu in rat cortex,hippocampus,and hypothalamus,and the most significant increase in hypothalamus. The immunohistochemistry and Western blot results showed that T can up-regulate the expression of GAD67 protein in hypothalamus,and the PCR results showed that T can up-regulate the expression of GABAA Rα1,α2,α3,α5,β1-3,γ1-3 genes,suggesting a sedative effect through the GABAergic nervous system. In conclusion,this study shed insight into the theoretical basis and clinical application of S. pinnatifolia,and also provides inspiration for subsequent development and application.
Keywords: GABAergic nervous system; Mongolian folk medicine; Syringa pinnatifolia; analgesic; sedative.