Antinociceptive Effects of Ginsenosides Injected Intracerebroventricularly or Intrathecally in Substance P-Induced Pain Model

We have examined the effects of several ginsenosides (R b1 , R b2 , R c , R d , R e , R f , R g1 and R g3 ) adminstered intracerebroventricularly ( i. c. v. ) or intrathecally ( i. t. ) on the nociceptive behavior induced by substance P (0.7 μg) injected i. t. Among the several ginsenosides studied, R b2 , R c , R d , and R e , but not R b1 , R f , R g1 and R g3 , treated i. c. v. (50 μg) attenuated the nociceptive behavior induced by substance P injected i. t. On the other hand, we found that i. t. treatment with 50 μg of R b1 , R b2 , R d , or R f effectively attenuated the nociceptive behavior induced by i. t. injected substance P. However, the i. t. treatment with the same doses of R c , R e , R g1 or R g3 was not effective for antagonizing i. t. injected substance P-induced nociceptive behavior. Our results show that ginsenosides R b2 , R c , R d , or R e injected supraspinally exert a antinociceptive effect in the substance P-induced pain model. Furthermore, R b1 , R b2 , R d , or R f treated spinally produce antinociception in the substance P-induced pain model. Abbreviations i.c.v.:intracerebroventricular i.t.:intrathecal S.E.M.:Standard error of the means Key Words Ginsenosides - Panax ginseng C.A. Meyer - Araliaceae - antinociception - supraspinal - spinally - substance P pain model - mouse