(-)-
Linalool is a natural compound with anti-inflammatory and antinociceptive properties. The antinociceptive action of
linalool has been reported in several models of inflammatory
pain. However, its effects in
neuropathic pain have not been investigated. Here, we used the spinal nerve
ligation (SNL) model of
neuropathic pain and studied the effects of acute and chronic administration of an established antinociceptive dose of
linalool on mechanical and thermal sensitivity induced by the nerve injury in mice.
Linalool did not affect
pain behavior triggered by mechanical or thermal stimuli when administered as a single dose before SNL. However,
mechanical allodynia was reduced transiently in neuropathic animals when
linalool was administered for 7 consecutive days, while no changes were seen in the sensitivity to noxious radiant heat. We investigated the possible involvement of the PI3K/Akt pathway in
linalool antinociceptive effect by western blot analysis.
Linalool did not induce significant changes in Akt expression and phopshorylation though a trend toward an increased ratio of phosphorylated versus total Akt was observed in SNL animals treated with
linalool, in comparison to SNL alone or
sham. We then wondered whether
linalool could modulate inflammatory processes and investigated spinal glia activation and IL-1beta contents following
linalool treatment in SNL animals. The data suggest that mechanisms other than an action on inflammatory processes may mediate
linalool ability to reduce
mechanical allodynia in this model of
neuropathic pain.