The analgesic activity of intrathecal tianeptine, an atypical antidepressant, in a rat model of inflammatory pain.

BACKGROUND

Tianeptine is an atypical antidepressant that exhibits structural similarities to the tricyclic antidepressants but has distinct neurochemical properties. We evaluated the antinociceptive activity of tianeptine and its mechanism of action regarding serotonergic and adrenergic transmission at the spinal level.

METHODS

The effects of intrathecally administered tianeptine and DUP-697 (a cyclooxygenase-2 inhibitor) were examined on flinching behavior evoked by intraplantar formalin injection, and their interaction was characterized using isobolographic analysis. Dihydroergocristine, prazosin, or yohimbine-which are serotonergic, α-1, and α-2 adrenergic receptor antagonists, respectively-were intrathecally administered 10 minutes before tianeptine to investigate its mechanism of action.

RESULTS

Intrathecally administered tianeptine and DUP-697 reduced the flinching response evoked by formalin injection during phases 1 and 2 in an additive fashion. Prazosin and yohimbine attenuated the antinociceptive effect of intrathecal tianeptine during both phases of the formalin test. Dihydroergocristine reversed the antinociception of tianeptine during phase 2, but not during phase 1.

CONCLUSIONS

Intrathecally administered tianeptine effectively relieved inflammatory pain in rats. The serotonergic system is related to the activity of tianeptine for facilitated pain at the spinal level. Adrenergic transmission is also involved in tianeptine-induced analgesia for both facilitated and acute pain. The combination of tianeptine and cyclooxygenase-2 inhibitor may provide additional benefits for the management of inflammatory pain.