ABSTRACT
Calendula Officinalis [Asteraceae] is widely used in traditional medicine as an anti-inflammatory agent and has also been reported to have anti-bacterial, anti-fungal and anti-viral activities. Sesquiterpene glycosides, saponins, triol, triterpenes and flavonoids are observed in its composition. The present study was designed to evaluate the antinociceptive effect of hydro-alcoholic extract of Calendula Officinalis in male rats. The animals were treated intraperitoneally with different doses of the Calendula Officinalis flower extract [100, 150 and 250 mg/kg body weight]. On the basis of the previous report the dose of 150 mg/kg is most effective. The analgesic activity was tested by tail flick and acetic acid-induced writhing tests. Data between experimental groups were compared by one way analysis of variance [ANOVA] followed by tukey's as post hoc test. All doses of the extract and also naloxone + extract [150mg/kg] significantly increased the tail flick latency compared to the control group. The extract of Calendula Officinalis significantly reduced the number of abdominal constrictions and stretching of hind limbs induced by the injection of acetic acid. Naloxone + extract [150mg/kg] significantly increased the number of writhing. From the results it could be concluded that the Calendula Officinalis extract exhibits anti-nociceptive activity. Analgesic effects of Calendula Officinalis have the same pathway as opioids, but just in the peripheral test [acetic acid-induced writhing test]
ABSTRACT
Introduction: Sildenafil, a phosphodiesterase-5 [PDE5] inhibitor, may have various effects on the central nervous system via the nitric oxide [NO]-cyclic guanosine monophosphate [cGMP] pathway. Preclinical studies have shown the controversial effect of sildenafil on anxiety-like behavior in animals. This study was undertaken to investigate the acute effect of sildenafil on anxiety-like behavior in mice. Methods: Male mice were intraperitoneally [i.p.] administrated sildenafil [1, 2, or 10 mg/kg], and the control group was given the vehicle 15 min before the plus-maze test. The number of entries into the open arms of the plus-maze, the time spent in the open arms, and the total numbers of entries into the arms were recorded. Results: The results indicated that compared to the control group, the sildenafiltreated mice spent more time in the open arms and had a greater number of entries into open arms. The total number of entries into the arms did not significantly differ between the sildenafil-treated groups and the control group. Discussion: Acute administration of sildenafil could have anxiolytic effects on male mice. This effect might be mediated in a time-dependent manner by the NO/ cGMP/PDE5 pathway