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- ItemSomente MetadadadosAntinociceptive effect of purine nucleotides(Assoc Bras Divulg Cientifica, 1996-10-01) Mello, C. F.; Begnini, J.; DeLaVega, D. D.; Lopes, F. P.; Schwartz, C. C.; JimenezBernal, R. E.; Bellot, Rogerio Gentil [UNIFESP]; Frussa-Filho, Roberto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)The antinociceptive effect of purine nucleotides administered systemically (sc) was determined using the formalin and writhing tests in adult male albino mice. The mechanisms underlying nucleotide-induced antinociception were investigated by preinjecting the animals (sc) with specific antagonists for opioid (naloxone, 1 mg/kg), purinergic P-1 (caffeine, 5, 10 or 30 mg/kg); theophylline, 10 mg/kg) or purinergic P-2 receptors (suramin, 100 mg/kg, Coomassie blue, 30-300 mg/kg; quinidine, 10 mg/kg). Adenosine, adenosine monophosphate (AMP), diphosphate (ADP) and triphosphate (ATP) caused a reduction in the number of writhes and in the time of licking the formalin-injected paw. Naloxone had no effect on adenosine- or adenine nucleotide-induced antinociception. Caffeine (30 mg/kg) and theophylline (10 mg/kg) reversed the antinociceptive action of adenosine and adenine nucleotide derivatives in both tests. P-2 antagonists did not reverse adenine nucleotide-induced antinociception. These results suggest that the antinociceptive effect of adenine nucleotides is mediated by adenosine.