L-arginine-Nitric oxide pathway plays an important role in a series of
neurobiological functions underlying behaviors including analgesic effect and has
shown a role in pain feeling which is a mediator with modulation effect in dorsal root
of ganglionic neurons of spinal cord. The goal of the present study is to clarify the
influence of L-arginine-mediated nitric oxide (NO) on pain arbitration in both sexes
of mice. The reactive time to thermal stimulus, latency period, tail withdrawal and the
number of foot licking and flinching in hot plate test, tail flick and formalin tests were
recorded. The results showed that L-NAME (nitric oxide synthase inhibitor) has had
an antinociceptive activity demonstrated as prolonged reactive time to thermal
stimulus, latency period for tail withdrawal and decreasing the number of foot licking
and flinching in hot plate, tail flick and formalin tests. These findings might be
attributed to that intensity of pain feeling is intercede due to interference of sex
hormones in both sexes of mice. In addition, from the results of L-NAME on pain
sensation, it may be concluded that L-arginine-nitric oxide pathway is extravital in
male in comparison with female in pain sensation.