The pyrazol compounds are known to possess antipyretic, analgesic and anti-inflammatory activities. This study was conducted to investigate the peripheral antinociceptive effect of the pyrazole compound 5-(1-(3-Fluorophenyl)-1H-pyrazol-4-yl)-2H-tetrazole (LQFM-021) and involvement of opioid receptors and of the NO/cGMP/K(ATP) pathway. The oral treatments in mice with LQFM-021 (17, 75 or 300 mg/kg) decreased the number of writhing. In the formalin test, the treatments with LQFM-021 at doses of 15, 30 and 60 mg/kg reduced the licking time at both neurogenic and inflammatory phases of this test. The treatment of the animals with LQFM-021 (30 mg/kg) did not have antinociceptive effects in the tail-flick and hot plate tests. Furthermore, pre-treatment with naloxone (3 mg/kg i.p.), L-name (10 mg/kg i.p.), ODQ (10 mg/kg i.p.) or glibenclamide (3 mg/kg i.p.) antagonized the antinociceptive effect of LQFM-021 in both phases of the formalin test. In addition, it was also demonstrated that the treatments of mice with LQFM-021(15, 30 and 60 mg/kg) did not compromise the motor activity of the animals in the chimney test. Only the highest dose used in the antinociceptive study promoted changes in the open field test and pentobarbital-induced sleep test, thus ruling out possible false positive effects on nociception tests. Our data suggest that the peripheral antinociception effects of the LQFM-021 were mediated through the peripheral opioid receptors with activation of the NO/cGMP/KATP pathway.

No abstract

No abstract

The molecular modification and synthesis of compounds is vital to discovering drugs with desirable pharmacological and toxicity profiles. In response to pyrazole compounds' antipyretic, analgesic, and anti-inflammatory effects, this study sought to evaluate the analgesic, anti-inflammatory, and vasorelaxant effects, as well as the mechanisms of action, of a new pyrazole derivative, 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole. During the acetic acid-induced abdominal writhing test, treatments with 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole reduced abdominal writhing, while during the formalin test, 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole reduced licking times in response to both neurogenic pain and inflammatory pain, all without demonstrating any antinociceptive effects, as revealed during the tail flick test. 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole also reduced carrageenan-induced paw edema and cell migration during the carrageenan-induced pleurisy test. As demonstrated by the model of the isolated organ, 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole exhibits a vasorelaxant effect attenuated by Nω-nitro-l-arginine methyl ester, 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one, tetraethylammonium or glibenclamide. 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole also blocked CaCl -induced contraction in a dose-dependent manner. Suggesting a safe toxicity profile, 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole reduced the viability of 3T3 cells at higher concentrations and was orally tolerated, despite signs of toxicity in doses of 2000 mg/kg. Lastly, the compounds' analgesic activity might be attributed to the involvement of the NO/cGMP pathway and K channels observed in the vasorelaxant effect.

No abstract