Role of GABA(B) receptor agonist baclofen in acute pain modulation during the early postnatal period.

Abstract

BACKGROUND: Baclofen, a specific GABA(B) receptor agonist, is used to treat spasticity and its off-label use includes the treatment of pain. The aim of this study was to show the role of baclofen in acute pain modulation during the early postnatal period. METHODS: Baclofen was tested in 2 doses (1 and 5 mg/kg) in 3 age groups (postnatal days 7, 16 and 21) in order to assess its effect on acute nociception and motor co ordination in rat pups. Pain was evaluated by measurement of paw/tail withdrawal latencies, and motor coordination by age-relevant tests. RESULTS: Although baclofen impaired motor function in all age groups, no changes in paw withdrawal latencies were observed. On the other hand, baclofen significantly increased tail withdrawal latencies of all groups. CONCLUSION: It is concluded that the GABA(B) system is functionally matured in the early postnatal period and plays a similar, but not the same, role as in adulthood.