Involvement of GABA in the antinociceptive effect of gamma-acetylenic GABA (GAG), an inhibitor of GABA-transaminase

The role of both novel GABAB and classical GABAA receptors in GAG-induced anti-nociception was investigated using the tail flick and hot plate tests. To this end, manipulations known to increase baclofen-induced antinociception (GABAB) and the receptor antagonist bicuculline (GABAA) were used. Of the modifiers of monoamine function tested, only chlorpromazine and haloperidol significantly increased GAG-induced antinociception. Theophylline antagonized antinociception produced by both GAG and GVG. Bicuculline did not antagonize antinociception produced by either GAG or muscimol. GAG-induced antinociception does not appear to result from the activation of either classical or novel GABA receptors. An interaction with dopaminergic pathways appears to be involved.