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. Doseeffect 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.
These results suggest that memory enhancement by spermidine is prevented by the nonspecific nitric oxide synthase inhibitor L: -NAME.
Surfactants are frequently used to improve solubilization of lipophilic drugs. Cremophor EL (CrEL) is a polyoxyethylated castor oil surfactant used to solubilize water-insoluble drugs such as anesthetic, antineoplastic, immunosuppressive and analgesic drugs, vitamins and new synthetic compounds, including potential analgesics. The antinociceptive effect of CrEL (3.2, 6.4 and 10.6 g/kg, in 10 ml/kg body weight, by gavage) on the abdominal writhing response induced by intraperitoneal administration of acetic acid (0.8%, 10 ml/kg body weight) and on the tail immersion test was investigated in mice. Control animals received castor oil (10 ml/kg body weight) or saline (0.9% NaCl, 10 ml/kg body weight). CrEL reduced nociception in a dose-dependent manner in both tests. At 10.6 g/kg, CrEL caused antinociception similar to that induced by dipyrone (300 mg/kg, by gavage) in the abdominal writhing test, and antinociception similar to that induced by morphine (20 mg/kg, by gavage) in the tail immersion test. The effect of castor oil was similar to that of saline in both assays. These data indicate that the appropriate controls should be used when evaluating the effects of potential antinociceptive agents dissolved in CrEL.
Authors searched actions of Cymbopogon citratus-Stapf aquous extract, 2% concentration, on montility of smooth muscle. It were performed 10 (ten) experiments, each of them consisted of the motility record of a segment of duodenum from male Wistar rats maintained in a Tyrode solution water-bath to isolated organ. Physiological parameters (temperature, pH, oxigen supply) were controled to obtain the functional nature of organ motility. It were realized three records to each experiment in this sequency: First record: control record (standard) from motility of duodenum smooth muscle in Tyrode bath. Second record: after addition of 0,5 ml physiological solution before the third record, the bath liquid was entirely substituted and the organ was washed tith Tyrode solution. Third record: after 15 (fifteen) minutes from the addition of Cymbopogon citratus-Stapf tea 2% concentration, it was add 0,5ml acetylcholine solution (11,8165 Mg in 50 ml physiological solution).It was verified that it shows a significant difference between 2nd and third record groups compared whit control records (first record groups) on smooth muscle motility of isolated duodenum from Wistar male rats.
Stevia rebaudiana (Bert) Bertoni is a wild herb that grows in Brazil (South Mato Grosso) and Paraguay, being used by natives as a sweetener and as medicine. According to these properties, the authors investigated effects of the aquous extract of this plant on immature Wistar rats corporal weight and food and liquid ingestion, using three different concentrations, through oral application. Solutions were prepared by cold infusion and used in four animal groups, ten animals each. Three experimental groups received Stevia solution at 1%, 2% and 4% respectively. The fourth, control, received destilled water. The animals were males and females and were maintained in the same experimental conditions, receiving during 49 days water and food "ad libitum". The corporal weight was verified every seven days and the results showed that Stevia rebaudiana, in the given concentrations, did not modify the animals' corporal weight, nor altered normal weight variations, since they were in growth phase.
Animals poisoning by ingestion of Ramaria flava brunnescens fungus found in Eucalipto groves is common in Southern Brazil. This poisoning does not have an effective antidote yet and it is common to avoid the toxicity by removing the animals from these fields or by using atropin when fungus intoxication signals appear. Present work was reallized to elucidate the manner and place of action of this fungus aqueous extract on isolated guinea pig ileum. For this purpose, we used Magnus Bath and strain transducer to Physiograph connect. Experiences were realized with 18 ileum tested with 10 mcg Nicotine. 24.600 mcg Ramaria flavo brunnescens fungus' aqueous extract and 30 mcg Hexametonium. Those concentrations were choosen from pilot experiences. The results showed that uses of this fungus extract provokes smooth muscle contraction similar to that of nicotin, the difference between both occurs due to Hexametone blockade impossibility. This fact suggests that the death mechanism of animals that eat this fungus is not due to ganglionar stimulation.
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