The Gaba B Receptor Agonist Baclofen Attenuates Neuropathic Pain In Mice

Background: Neuropathic pain is pain arising from dysfunction of the peripheral or central nervous system. It is a chronic pain and a disastrous health problem causing burden to the patient quality of life, productivity and health care cost. The dysfunction of GABA-ergic system (GABA-ergic inhibition) can cause neuropathic pain. Baclofen, a GABA B agonist, acts by restoring inhibitory neurotransmitter, GABA. Baclofen inhibits presynaptic calcium channel and postsynaptic kalium channel and adenylate cyclase Enzyme. Objective: To assess the effectiveness of GABA B agonist baclofen in reducing neuropathic pain in mice. Method: 3 - 5 mice per group (total 5 groups) were classified into two major categories i.e. Sham (control) or Ligation. Mice-modelled neuropathic pain was induced using ligation of the sciatic nerve by procedure described by Bennet and Xie. Three groups of mice received intrathecal administration of baclofen of1,10 or 30 nmol whereas two groups received only normal saline for 7 consecutive days(at 7- 14 days post surgical procedure). Hyperalgesia was measured using Hot Plate Test at day 0,3,5,7,9,11,and 14.Data were analysed usingTwo Way Anova. Result: Bennet and Xie procedure successfully developed neuropathic pain in which this was shown by significantly different between Sham and Ligation group (F (1 17) = 3,46 ; p=0,02). All doses of 1, 10 and 30 nmol baclofen resulted in increasing response time to thermal stimulus compared with normal saline ligation group. However, the statistical analysis of all doses showed no significant different and thus 1nmol baclofen might an optimal dose in reducing neuropathic pain for this experiment. Furthermore, baclofen as GABA B agonist showed partial treatment response in managing neuropathic pain which it is rationale considering baclofen as only GABA-B receptor agonist while there are many mechanisms contributing to the development of neuropathic pain. Therefore, a combination therapy with other agents is essential for managing neuropathic pain. Conclusion: Baclofen is effective for managing neuropathic pain in this mice model. The partial treatment response with baclofen necessitates a combination therapy strategy