Antinociceptive effect of novel pyrazolines in mice

Brazilian Journal of Medical and Biological Research

Z. Tabarelli²  M.a. Rubin¹  D.b. Berlese¹  P.d. Sauzem¹  T.p. Missio¹  M.v. Teixeira¹  A.p. Sinhorin¹  M.a.p. Martins¹  N. Zanatta¹  H.g. Bonacorso¹  C.f. Mello² 

[1] ,Universidade Federal de Santa Maria Centro de Ciências da Saúde Departamento de Fisiologia

关键词: Pyrazole-derived compounds;    Antinociception;    Tail immersion test;    Rotarod test;    Open-field test;    Immobility;   

DOI  :  10.1590/S0100-879X2004001000013

来源: SciELO

【 摘 要 】

The antinociceptive effect of six novel synthetic pyrazolines (3-ethoxymethyl-5-ethoxycarbonyl-1H-pyrazole (Pz 1) and its corresponding 1-substituted methyl (Pz 2) and phenyl (Pz 3) analogues, and 3-(1-ethoxyethyl)-5-ethoxycarbonyl-1H-pyrazole (Pz 4) and its corresponding 1-substituted methyl (Pz 5) and phenyl (Pz 6) analogues) was evaluated by the tail immersion test in adult male albino mice. The animals (N = 11-12 in each group) received vehicle (5% Tween 80, 10 ml/kg, sc) or 1.5 mmol/kg of each of the pyrazolines (Pz 1-Pz 6), sc. Fifteen, thirty and sixty minutes after drug administration, the mice were subjected to the tail immersion test. Thirty minutes after drug administration Pz 2 and Pz 3 increased tail withdrawal latency (vehicle = 3.4 ± 0.2; Pz 2 = 5.2 ± 0.4; Pz 3 = 5.9 ± 0.4 s; mean ± SEM), whereas the other pyrazolines did not present antinociceptive activity. Dose-effect curves (0.15 to 1.5 mmol/kg) were constructed for the bioactive pyrazolines. Pz 2 (1.5 mmol/kg, sc) impaired motor coordination in the rotarod and increased immobility in the open-field test. Pz 3 did not alter rotarod performance and spontaneous locomotion, but increased immobility in the open field at the dose of 1.5 mmol/kg. The involvement of opioid mechanisms in the pyrazoline-induced antinociception was investigated by pretreating the animals with naloxone (2.75 µmol/kg, sc). Naloxone prevented Pz 3- but not Pz 2-induced antinociception. Moreover, naloxone pretreatment did not alter Pz 3-induced immobility. We conclude that Pz 3-induced antinociception involves opioid mechanisms but this is not the case for Pz 2.

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