RESUMO
PURPOSE: This study was designed to evaluate the antihyperalgesic effect of CDP-choline (cytidine-5'-diphosphate- choline; citicoline) in a rat model of neuropathic pain produced by oxaliplatin (OXA). METHODS: A single administration of OXA (6 mg/kg intraperitoneally/ ip) was used for induction of neuropathy. We assessed the antihyperalgesic effect of intracerebroventricularly (icv) administered CDP-choline (0.5, 1.0 and 2.0 µmol) using the rat paw pressure test (Randall-Selitto). RESULTS: CDP-choline significantly reduced OXA-induced mechanical hyperalgesia, in a dose- and time-dependent manner. The antihyperalgesic effect of CDP-choline was blocked by the neuronal high affinity choline uptake inhibitor hemicholinium-3 (1 µg; icv), the nonselective nicotinic receptor antagonist mecamylamine (50 µg; icv), the α7 selective nicotinic acetylcholine receptor antagonist α-bungarotoxin (2 µg; icv), and the gamma-amino butyric acid (GABA)-B receptor antagonist CGP-35348 (20 µg; icv), but not by the nonselective opioid receptor antagonist naloxone (10 µg; icv) and the nonselective muscarinic receptor antagonist atropine (10 µg; icv). CONCLUSION: These findings indicate that CDP-choline exerts an antihyperalgesic effect in OXA-induced neuropatic pain and it can be tested in clinical trials.
