ABSTRACT
@#Introduction: Intracerebroventricular administration of streptozotocin (icv-STZ) induced apoptosis changes in neurons similar to Alzheimer's disease. The serotonergic system via its receptor involved in survival of neurons. The present study examined the ability of selective 5-HT1A receptor antagonist (NAD-299) and 5-HT2A receptor agonist (TCB-2) to attenuate the apoptosis caused by the icv-STZ in the rat. Methods: The icv-STZ (3 mg/kg, 10 μL, twice) induced neuronal loss in the hippocampus of adult male rats. Animals were divided into naive control, sham-operated, STZ+saline (1 μL, icv), STZ+NAD-299 (5 μg/μL, icv), STZ+TCB-2 (5 μg/μL, icv), and STZ+NAD-299+TCB-2 (5 μg/μL of any agent, icv) groups. Following the 35 days’ treatment period, neuronal apoptosis was detected using the Tunnel. Cells with morphological features of apoptotic cell were contended by microscopy. Results: TCB-2 and NAD-299 administration decreased number of apoptotic neurons in the treatment group compared with the STZ group. Combined treatment of STZ rat with NAD+TCB more decreased number of apoptotic cells in compare to TCB-2 or NAD-299 treated STZ groups. Conclusion: Treatment with 5-HT1A receptor antagonist or 5-HT2A receptor agonist diminished apoptosis. The beneficial effect of 5HT1A receptor inhibition was potentiated with activation of 5-HT2A receptor in prevention of apoptosis in hippocampus.
ABSTRACT
Background: Role of medicinal plants on enhancement of memory and improvement of Alzheimer's disease symptoms has attracted many researchers. Salvia leriifolia has several properties including anti-oxidant, anti-inflammatory and anti-anxiety. At this study, effect of ethanolic extract of Salvia leriifolia leaf on scopolamine-induced memory impairment was evaluated
Materials and methods: In this experimental study, 48 male Wistar rats were randomly divided into six groups of eight subjects for investigating effect of Salvia leriifolia ethanolic extract on memory in normal rats and effective dose on scopolamine-induced memory impairment: control received saline, extract with 100, 200 and 400 mg/kg doses, scopolamine with 1 mg/kg dose, and scopolamine [1 mg/kg] and extract effective dose [200 mg/kg] co-administration. The memory was evaluated by passive avoidance test. The step-through latency [STL] for entering the dark compartment and time spent in dark compartment [TDC] were measured
Results: Intraperitoneal injection of various doses of the extract caused significant difference in mentioned parameters. TDC was reduced in all groups treated by extract [p<0.001] and STL increased in doses of 100 [p<0.05] and 200 mg/Kg [p<0.001] than the control, significantly. Maximum effect on memory was shown in 200 mg/kg dose of extract. The effective dose of extract [200 mg/kg] enhanced memory and improved scopolamine-induced memory impairment
Conclusion: Salvia leriifolia extract has enhancing and improving effects on memory
ABSTRACT
Introduction: Previous studies have shown that cannabinoidergic system is involved in anxiety. However, there are controversial reports in the experimental studies. The aim of this study is to evaluate the effect of pharmacological stimulation or blocking of CB1 receptors and inhibition of endocannabinoid degradation in anxiety like behavior in elevated plus-maze [EPM] test in rat. The EPM is one of the most widely used animal models of anxiety
Methods: Male Wistar rats were randomly allocated to ten groups. Different groups of animals intraperitoneally received Win-55212 [0.3, 1 and 5 mg/kg] as CB1 receptor agonist, AM- 251 [0.3, 1 and 5 mg/kg] as CB1 receptor antagonist, URB-597 [0.03, 0.1 and 0.3 mg/kg] as endocannabinoid breakdown inhibitor or saline [as control group] 30 min before submitting into EPM test
Results: The results showed that compared to the control group, Win-55212 [1 and 5 mg/kg] and URB-597 [0.1 and 0.3 mg/kg] significantly increased both of the time and percentage of entries into open arms. AM-251 [1 and 5 mg/kg] significantly decreased the time and percentage of entries into open arms in the EPM test. These substances have no effects on the total distance covered by animals and number of closed arm entries
Discussion: It is concluded that activation of cannabinoid receptor exert anxiolytic effect while blocking of cannabinoid receptor resulted in anxiety behavior. The locomotor activity was not significantly changed by cannabinoid system. It is suggested that potentiation of cannabinoid system may be therapeutic strategy for the anxiety behavior
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: The role of serotonergic fibers in avoidance learning is controversial. Involvement of the dorsal raphe nucleus [DRN], the main source of hippocampal projecting serotonergic fibers in acquisition, consolidation and retrieval of passive avoidance [PA] learning, was investigated by functional suppression of this area. Materials and Methods: DRN functional inactivation was done by lidocaine [0.5µl, 2%] injection into the DRN, 5 min before training [n=10]; and 5 [n=9], 90 [n=10] and 360 min [n=9] after acquisition trial. In the last experiment, lidocaine was injected into the DRN 5 min before the retrieval test, which was 48 h after the training [n=10]. Results: Our results showed that PA learning was not impaired by DRN inactivation 5 min before training nor 5 and 360 min after training. Lidocaine injected 90 min after the acquisition trial significantly reduced avoidance of the dark compartment [P<0.001]. Intra-DRN injection of lidocaine before retrieval significantly increased PA retention [P<0.001]. Therefore, it seems that DRN has opposite effects on consolidation and retrieval of passive avoidance learning, but it has no effect on PA acquisition. Discussion: It is suggested that functional ablation of DRN may disrupt integrity of subcortical circuits participating in PA consolidation, but DRN inactivation by increasing brain awareness may affect PA retrieval in rats
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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
ABSTRACT
The nucleus raphe magnus [NRM] is involved in thermoregulatory processing. There is a correlation between changes in the firing rates of the cells in the NRM and the application of the peripheral thermal stimulus. We examined the effect of reversible inactivation and excitation of NRM on mechanisms involved in tail blood flow [TBF] regulation in hypothermia. Hypothermia was induced in Male Wistar rats and cannula was implanted above the NRM. To evaluate the effect of nucleus inactivation on TBF, the amount of TBF was measured by Laser Doppler in hypothermic rats, before and after lidocaine microinjection into NRM. TBF was also measured after glutamate microinjection to assess the effect of nucleus excitation in hypothermic rats. Results indicated that after dropping TBF by hypothermia, microinjection of lidocaine into NRM significantly decreased TBF from 54.43 +/- 5.7 to 46.81 +/- 3.4, whereas glutamate microinjection caused a significant increase from 44.194 +/- 0.6 to 98 +/- 10.0 Conclusion: These data suggest that NRM have thermoregulatory effect in response to hypothermia