Figure 3.

Mean±SEM concentration of 3-methoxy-4-hydroxyphenylglycol (MHPG) in four study groups

*: Significant difference with group 1, 3 and 4

* *: Significant difference with group 1, 2 and 3

Fraction numbers are according to collection of microdialysis samples every 15 min

Group one (main control or control of formalin and tramadol test): injection of normal saline (IP) and injection of normal saline (SC) in right hind paw

Group two (control of tramadol test): injection of normal saline

(IP) and injection of formalin (SC) in right hind paw

Group three (control of formalin test): injection of tramadol (IP)

and injection of normal saline (SC) in right hind paw

Group four (main test group test): injection of tramadol (IP) and

injection of formalin (SC) in hind paw