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


CONCLUSIONS
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.
Franek
Miloslav
M
Department of Normal, Pathological and Clinical Physiology, Charles University, Prague, Czech Republic. franek@lf3.cuni.cz
Vaculin
Simon
S
D000208:Acute Disease; D000367:Age Factors; D000818:Animals; D001418:Baclofen / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D018755:GABA Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D058786:GABA-B Receptor Agonists; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010146:Pain / Q000188:drug therapy* / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar
D018755:GABA Agonists; D058786:GABA-B Receptor Agonists; D001418:Baclofen