Antidepressant-like effect of rutin isolated from the ethanolic extract from Schinus molle L. in mice: evidence for the involvement of the serotonergic and noradrenergic systems

We have recently shown that the hexanic extract from leaves of Schinus molle produces antidepressant-like effects in the tail suspension test in mice. This study investigated the antidepressant-like effect of the ethanolic extract from aerial part of S. molle in the forced swimming test and tail suspension test in mice, two predictive models of depression. Moreover, we investigated the antidepressant potential of rutin, a flavonoid isolated from the ethanolic extract of this plant and the influence of the pretreatment with the inhibitors of serotonin or noradrenaline synthesis, p-chlorophenylalanine methyl ester (PCPA) and alpha-methyl-p-tyrosine (AMPT), respectively in the antidepressant-like effect of this flavonoid. The administration of the ethanolic extract produced a reduction in the immobility time in the tail suspension test (dose range 600-1000 mg/kg, p.o.), but not in the forced swimming test. It also produced a reduction in the ambulation in the open-field test in mice not previously habituated to the arena, but no effect in the locomotor activity in mice previously habituated to the open-field. The administration of rutin reduced the immobility time in the tail suspension test (0.3-3 mg/kg, p.o.), but not in the forced swimming test, without producing alteration in the locomotor activity. In addition, pretreatment of mice with PCPA (100 mg/kg, i.p., for 4 consecutive days) or AMPT (100 mg/kg, i.p.) prevented the anti-immobility effect of rutin (0.3 mg/kg, p.o.) in the tail suspension test. The results firstly indicated the antidepressant-like effect of the ethanolic extract of S. molle in the tail suspension test may be dependent on the presence of rutin that likely exerts its antidepressant-like effect by increasing the availability of serotonin and noradrenaline in the synaptic cleft.     

Evidence for involvement of the monoaminergic system in antidepressant-like activity of an ethanol extract of Boerhaavia diffusa and its isolated constituent,punarnavine, in mice

Context: Boerhaavia diffusa Linn. (Nyctaginaceae) roots possess potent antioxidant, antistress, and anticonvulsant activities. It is used as a medicinal plant in Ayurvedic and natural herbal medicines.

Objective: To evaluate the effect of Boerhaavia diffusa root ethanol extract and its active constituent, punarnavine, on depression in Swiss albino mice.

Materials and methods: Ethanol extract (50, 100, and 200?mg/kg, p.o.) and punarnavine (20 and 40?mg/kg, p.o.) were separately administered to 22 and 17 groups of mice, respectively, for 14 successive days followed by testing in the tail suspension and forced swim tests (FST). About 2% w/v gum acacia and double distilled water were used as controls for the extract and punarnavine, respectively.

Results: Antidepressant-like effect of the lowest dose (50?mg/kg) of the extract and lower dose (20?mg/kg) of punarnavine were found to be comparable to fluoxetine. The ED₅₀ value of the ethanol extract was 26.30?mg/kg (FST) and 33.11?mg/kg (tail suspension test); and of punarnavine was 15.14?mg/kg (FST) and 17.38?mg/kg (tail suspension test). The drugs did not show any significant effect on locomotor activities of mice. Prazosin (α₁-adrenoceptor antagonist), sulpiride (selective D₂-receptor antagonist), para-chlorophenylalanine) (p-CPA) (tryptophan hydroxylase inhibitor), and baclofen (GABA_B agonist) significantly attenuated the extract and punarnavine induced-antidepressant-like effect in the tail suspension test. The extract and punarnavine also significantly reduced mouse brain monoamine oxidase (MAO)-A levels, but there was no significant effect on plasma corticosterone levels.

Conclusion: Ethanol extract of Boerhaavia diffusa and punarnavine produced an antidepressant-like effect in mice probably through interaction with monoaminergic and GABAergic systems.     

Effect of Morus alba L. (mulberry) leaves on anxiety in mice

Objective:

The aim of the present work is to evaluate the anxiolytic effect of a methanolic extract of Morus alba L. leaves in mice.

Materials and Methods:

The hole-board test, elevated plus-maze paradigm, open field test, and light/dark paradigm were used to assess the anxiolytic activity of the methanolic extract of M. alba L. Morus alba extract (50, 100, and 200 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.) were administered 30 min before the tests.

Results:

The results showed that the methanolic extract of M. alba significantly increased the number and duration of head poking in the hole-board test. In the elevated plus-maze, the extract significantly increased the exploration of the open arm in similar way to that of diazepam. At a dose of 200 mg/kg i.p. the extract significantly increased both the time spent in and the entries into the open arm by mice. Further, in the open field test, the extract significantly increased rearing, assisted rearing, and number of squares traversed, all of which are demonstrations of exploratory behavior. In the light/dark paradigm, the extract produced significant increase in time spent in the lighted box as compared to vehicle. The spontaneous locomotor activity count, measured using an actophotometer, was significantly decreased in animals pretreated with M. alba extract, indicating a remarkable sedative effect of the plant.

Conclusion:

The results of the present study suggest that a methanolic extract of M. alba leaves may possess an anxiolytic effect.     

Central nervous system effects of the essential oil of the leaves of Alpinia zerumbet in mice

Objectives Alpinia zerumbet, known in Brazil as colônia, is popularly used as a diuretic, antihypertensive, anti‐ulcerogenic and sedative. Based on this, we have investigated the central effects of the essential oil isolated from A. zerumbet leaves. Methods Mice were treated once with 50 or 100 mg/kg of the essential oil, intraperitoneally, 30 min before being submitted to behavioural models of: locomotor activity (open‐field), catalepsy, anxiety (elevated plus maze), depression (forced swimming test and tail suspension tests) as well as apomorphine‐induced stereotypy. Key findings Results showed a dose‐related decrease on locomotor activity and apomorphine‐induced stereotypy. There was a decrease to the order of 55% of the grooming behaviour with both doses studied. The essential oil 100 mg/kg increased cataleptic activity (167%) and the immobility time in the forced swimming and tail suspension tests. Pretreatment with haloperidol (0.2 mg/kg, i.p.) alone also decreased locomotion, increased cataleptic activity and immobility time in the tail suspension test. No alterations in the elevated plus maze test were registered. Conclusions The essential oil of A. zerumbet leaves had depressant and possible antipsychotic activity, since it could reverse the stereotypy induced by apomorphine, presenting effects comparable with those obtained with haloperidol treatment.     

Anxiolytic and antidepressant-like effects of the hydroalcoholic extract from Aloysia polystachya in rats

Behavioral effects of a hydroalcoholic extract from leaves of Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) were studied in female Sprague-Dawley rats. The extract was administered intraperitoneally and its effects on spontaneous motor activity (total motility, locomotion, rearing and grooming behavior) were monitored. Anxiolytic-like properties were studied in the elevated plus-maze (EPM) test and the possible antidepressant-like actions were evaluated in the forced swimming test (FST). The results revealed that high doses of the extract (25 and 50 mg/kg, i.p.) caused a significant decrease in total motility, locomotion, rearing and grooming behavior. All doses injected (from 1.56 to 50 mg/kg) increased the exploration of the EPM open arms in a similar way to that of diazepam (1 mg/kg, i.p.). In the FST, the extract (12.5, 25 and 50 mg/kg) was as effective as fluoxetine (10 mg/kg, i.p.) and imipramine (12.5 mg/kg, i.p.) in reducing immobility, along with a significant increase in swimming and climbing, respectively. These results suggest that some of the components of the hydroalcoholic extract of A. polystachya, such as thujone and carvone among others, may have sedative, anxiolytic and antidepressant-like properties which deserve further investigation.     

Myrica nagi Attenuates Cumene Hydroperoxide‐Induced Cutaneous Oxidative Stress and Toxicity in Swiss Albino Mice

In recent years, considerable efforts have been made to identify new chemopreventive agents which could be useful for man. Myrica nagi, a subtropical shrub, has been shown to possess significant activity against hepatotoxicity and other pharmacological and physiological disorders. We have shown a chemopreventive effect of Myrica nagi on cumene hydroperoxide‐induced cutaneous oxidative stress and toxicity in mice. Cumene hydroperoxide treatment at a dose level of 30 mg/animal/0.2 ml acetone enhances susceptibility of cutaneous microsomal membrane for iron‐ascorbate‐induced lipid peroxidation and induction of xanthine oxidase activity which are accompanied by decrease in the activities of cutaneous antioxidant enzymes such as catalase, glutathione peroxidase, glutathione reductase, glucose‐6‐phosphate dehydrogenase and depletion in the level of cutaneous glutathione. Parallel to these changes a sharp decrease in the activities of phase II metabolizing enzymes such as glutathione S‐transferase and quinone reductase has been observed. Application of Myrica nagi at doses of 2.0 mg and 4.0 mg/kg body weight in acetone prior to that of cumene hydroperoxide (30 mg/animal/0.2 ml acetone) treatment resulted in significant inhibition of cumene hydroperoxide‐induced cutaneous oxidative stress and toxicity in a dose‐dependent manner. Enhanced susceptibility of cutaneous microsomal membrane for lipid peroxidation induced by iron ascorbate and xanthine oxidase activities were significantly reduced (P<0.05). In addition the depleted level of glutathione, the inhibited activities of antioxidants, and phase II metabolizing enzymes were recovered to a significant level (P<0.05). The protective effect of Myrica nagi was dose‐dependent. In summary our data suggest that Myrica nagi is an effective chemopreventive agent in skin and capable of ameliorating cumene hydroperoxide‐induced cutaneous oxidative stress and toxicity.     

Hydroalcoholic extract of Urtica circularis: A neuropharmacological profile

Abstract

Context: The genus Urtica has been known since ancient times. It has known to be useful for the treatment of different human ailments.

Objective: The present work evaluated the neuropharmacological effects of a hydroalcoholic extract of Urtica circularis (Hicken) Sorarú (Urticaceae).

Materials and method: The effect on central nervous system of U. circularis hydroalcoholic extract (from leaves and stems) administered by the intraperitoneal route in mice was evaluated by several tests: Pentobarbital- and midazolam-induced hypnosis, open field, hole board, elevated plus-maze and forced swimming. Phytochemical analysis was performed by high-performance liquid chromatography.

Results: A total of 300?mg/kg i.p. of the extract produced a significant prolongation of pentobarbital- (40?mg/kg i.p.; 60.1?min versus 25.4?min) and midazolam- (50?mg/kg i.v.; 53.4?min versus 25.1?min) induced sleeping time. The extract’s administration caused a marked reduction of the head-dipping response (DE₅₀: 373?mg/kg i.p.) in the hole-board test. Urtica circularis extract (DE₅₀: 46?mg/kg i.p.) reduced the spontaneous locomotor activity in the open field test. Flumazenil and atropine significantly antagonized the extract’s effect on the locomotor activity. No motor coordination disturbance was observed in the rota rod test at any doses. In the forced swimming test, the extract did not produce any change in the immobility time and it had no significant effects in elevated plus maze test. The phytochemical analysis revealed the presence of chlorogenic acid, vanillic acid, caffeic acid, vicenin-2, p-cumaric acid, ferulic acid, vitexin and isovitexin.

Conclusion: This study revealed that U. circularis hydroalcoholic extract possesses sedative activity, facilitating GABAergic and cholinergic transmission.     

The antidepressant-like effect of Hedyosmum brasiliense and its sesquiterpene lactone, podoandin in mice: evidence for the involvement of adrenergic, dopaminergic and serotonergic systems

We have recently shown that the ethanol extract of the leaves of Hedyosmum brasiliense exhibits an antidepressant-like effect in the tail suspension and forced swimming tests in mice. The present study investigates the mechanisms involved in the antidepressant-like effect of H. brasiliense extract, together with the antidepressant potential of podoandin, an isolated sesquiterpenoid. H. brasiliense (50mg/kg, i.p.) and podoandin (10mg/kg, i.p.) decreased the immobility time in the forced swimming test, without any accompanying changes in ambulation in the open-field test. The anti-immobility effect of the H. brasiliense extract was prevented by pre-treating the mice with ondansetron, NAN 190, pindolol, prazosin, yohimbine, haloperidol, SCH23390, and sulpiride. On the other hand, pre-treating the mice with: p-chlorophenylalanine (4 consecutive days), ketanserin, naloxone, naltrindole, bicuculline, phaclofen, or l-arginine did not block the antidepressant-like effect of H. brasiliense. In addition, pre-treatment of the animals with methylene blue, NG-nitro-l-arginine or 7-nitroindazole, at subeffective doses, did not cause a synergistic effect with H. brasiliense extract at an effective dose in the forced swimming test. The anti-immobility effect of podoandin was also prevented by pre-treating the mice with NAN-190, ondansetron, prazosin, yohimbine, sulpiride and haloperidol. The results indicate that the antidepressant-like effect of H. brasiliense (and podoandin) is dependent on the serotonergic, noradrenergic and dopaminergic systems, but not on the GABAergic, opioid and oxidonitrergic systems.     

Evaluation of the neuropharmacological effects of Gardenin A in mice

This work describes the neuropharmacological (sedative, anxiolytic, antidepressant, and anticonvulsant) actions of Gardenin A (GA) (0.1–25 mg/kg p.o.), a flavonoid found in medicinal plants. The sedative effects of GA were assessed with the pentobarbital-induced sleep test. The anxiolytic actions of GA were evaluated with the elevated plus-maze, the light–dark box test, the exploratory cylinder assay, and the open field test. Motor coordination was evaluated with the rotarod test and the open field test. The antidepressant-like actions of GA were evaluated with the tail suspension test and forced swimming test. The mechanisms of the anxiolytic-like and antidepressant-like effects of GA were assessed using inhibitors of neurotransmission pathways. The anticonvulsant activity of GA was evaluated with the strychnine-induced seizure test. The sedative effects of GA were evident only at a dose of 25 mg/kg, which increased the duration of sleep but did not alter sleep onset. GA showed anxiolytic-like actions with activity comparable to that of clonazepam in all experimental tests. The GABA_A receptor antagonist bicuculline reversed the anxiolytic-like effects of GA. Furthermore, GA showed significant antidepressant-like actions in both models with activity comparable to that of fluoxetine. Yohimbine, an α2-adrenoceptor blocker, inhibited the antidepressant-like actions of GA. In addition, GA (1–10 mg/kg) did not affect locomotor coordination in mice and delayed the onset of convulsions. These findings suggest that GA induces anxiolytic-like effects and has anticonvulsant actions by the possible involvement of the GABAergic system. The antidepressant-like actions of GA may be mediated by noradrenergic neurotransmission.     

Antidepressant and anxiolytic activity of Lavandula officinalis aerial parts hydroalcoholic extract in scopolamine-treated rats

Context: Anxiety and depression are common in Alzheimer’s disease (AD). Despite some evidence, it is difficult to confirm Lavandula officinalis Chaix ex Vill (Lamiaceae) as an anxiolytic and antidepressant drug.

Objective: The effects of L. officinalis extract were studied in scopolamine-induced memory impairment, anxiety and depression-like behaviour.

Materials and methods: Male NMRI rats were divided into control, scopolamine alone-treated group received scopolamine (0.1?mg/kg) intraperitoneally (i.p.), daily and 30?min prior to performing behavioural testing on test day, for 12 continuous days and extract pretreated groups received aerial parts hydro alcoholic extract (i.p.) (100, 200 and 400?mg/kg), 30?min before each scopolamine injection. Memory impairment was assessed by Y-maze task, while, elevated plus maze and forced swimming test were used to measure anxiolytic and antidepressive-like activity.

Results: Spontaneous alternation percentage in Y maze is reduced by scopolamine (36.42?±?2.60) (p?≤?0.001), whereas lavender (200 and 400?mg/kg) enhanced it (83.12?±?5.20 and 95?±?11.08, respectively) (p?≤?0.05). Also, lavender pretreatment in 200 and 400?mg/kg enhanced time spent on the open arms (15.4?±?3.37 and 32.1?±?3.46, respectively) (p?≤?0.001). On the contrary, while immobility time was enhanced by scopolamine (296?±?4.70), 100, 200 and 400?mg/kg lavender reduced it (193.88?±?22.42, 73.3?±?8.25 and 35.2?±?4.22, respectively) in a dose-dependent manner (p?≤?0.001).

Discussion and conclusion: Lavender extracts improved scopolamine-induced memory impairment and also reduced anxiety and depression-like behaviour in a dose-dependent manner.     

远志醇提物对抑郁症模型小鼠的保护作用研究

目的:研究远志醇提物对抑郁症模型小鼠的保护作用。方法:通过小鼠悬尾实验、强迫游泳实验、慢性不可预知性应激+开场实验分析远志醇提物的抗抑郁作用。各小实验中雄性小鼠均分为模型对照(等容生理盐水)、氯米帕明(20mg·kg-1)和远志醇提物高、中、低剂量(10、5、2.5g·kg-1)组。结果:高、中、低剂量远志醇提物均可缩短抑郁症模型小鼠悬尾不动时间、游泳不动时间和增加移动格数。结论:远志醇提物对模型小鼠抑郁症状态有一定的改善作用。     

Involvement of GABAergic system in regulation of the anxiolytic- and antidepressant-like effects of Scrophularia striata extract in rats

Abstract

Context: Neuropsychiatric disorders, like anxiety and depression, are global problems for clinical researchers in neurology. Recently, some authors have shown neuroprotective and anti-inflammatory effects of Scrophularia striata Boiss (Scrophulariaceae) extract in rodents.

Objective: The purpose of the current study was to investigate the effects of S. striata extract on anxiety and depressant-like behaviors and find a possible mechanism for these impacts.

Materials and methods: In this study, the elevated plus-maze (EPM) and forced swimming test (FST), which are useful models for selective identification of anxiolytic and antidepressant drug effects in rodents, were used. We investigated the effects of S. striata ethanol extract at different doses (20, 50, 100, 160 and 220?mg/kg) on anxiety and depression behaviors in the EPM and FST, and then we assessed the role of γ-aminobutyric acid (GABA)_A receptor in modulation of the effects of S. striata extract in the brain.

Results: Our results showed that effective doses of S. striata (100 and 160?mg/kg) increased the percentages of open arm time and entries in the EPM and decreased immobility time in the FST in comparison with control group, indicating anxiolytic and antidepressant effects, respectively. Moreover, intracerebroventricular administration of GABA_A receptor agonist (muscimol; 1?µg/rat) enhanced the impact of S. striata, and GABA_A receptor antagonist (bicuculline; 1?µg/rat) blocked these effects in rats, indicating that significant interactions existed between S. striata and the GABAergic system in the brain.

Discussion and conclusion: Findings of this study suggest that anxiolytic and antidepressant effects of S. striata may be modulated via the GABAergic system.     

The active alkaloids of Gelsemium elegans Benth are potent anxiolytics

OBJECTIVE To investigated whether acute subcutaneous administration of G.elegans alkaloids(eg,gelsemine,koumine,gelsevirine,gelsenicine) were capable of exerting anxiolytic and antidepressant effects in mouse models of these disorders.METHODS We used two mouse models of anxiety(elevated plus-maze and light-dark transition model),and two mouse models of depression(forced swim test and tail suspension test) to examine whether the G.elegans alkaloids are capable of attenuating anxiety-and depressive-like behaviors.RESULTS Gelsemine,koumine and gelsevirine exhibited potent anxiolytic effects in both the elevated plus-maze and the light-dark transition model.Gelsenicine,on the other hand,had no effect on the behavioural response in either of the anxiety models.None of the G.elegans alkaloids exerted antidepressant effects in the forced swim test and the tail suspension test.Importantly,none of the G.elegans alkaloids impaired spontaneous motor activities.CONCLUSION Gelsemine,koumine and gelsevirine might serve as potential candidates for the treatment of anxiety-related disorders in clinical trials with human patients.     

Evaluation of n-hexane extract of Viola betonicifolia for its neuropharmacological properties

Viola betonicifolia (whole plant) has been used as a sedative and in various nervous disorders in Pakistani traditional medicines. The n-hexane extract of the whole plant of V. betonicifolia (HEVB) was investigated for neuropharmacological properties such as anxiolytic, muscle relaxant, sleep induction, antidepressant and sedative to ascertain its folk use. Anxiolytic activity was tested using the staircase test, while the muscle relaxing property of the extract was tested in various muscle relaxant paradigms, i.e. chimney test, traction test, rota rod and inclined plane. In anxiolytic and muscle relaxant tests, HEVB (0.3, 0.4 and 0.5?g/kg, i.p.), diazepam (1?mg/kg, i.p.) or distilled water (10?ml/kg i.p.) were administered 30, 60 and 90?min before performing the tests in mice. HEVB was also screened for a sleep-inducing effect. The antidepressant activity was determined by using the forced swimming test (FST), while line crossing in a special box was used for locomotor activity. HEVB showed a significant (P?<?0.05) dose-dependent anxiolytic action in the staircase test. In muscle relaxant paradigms, a dose-dependent muscle relaxation was observed. For the phenobarbitone sleep induction test, HEVB notably (P?<?0.05) reduced the latency time and increased the total sleeping duration. However, HEVB was devoid of any antidepressant activity, while the movements of mice were reduced significantly (P?<?0.05) in locomotor activity. The results suggest that HEVB has anxiolytic, muscle relaxant, sleep-inducing (sedative) activity and, thus, provides pharmacological justification for the use of this plant as a sedative and for the relief of various nervous disorders.     

Diphenyl diselenide exerts antidepressant-like and anxiolytic-like effects in mice: involvement of L-arginine-nitric oxide-soluble guanylate cyclase pathway in its antidepressant-like action

This study investigated the possible antidepressant-like and anxiolytic-like effects of diphenyl diselenide, (PhSe)(2) in mice. The involvement of L-arginine-nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway in the antidepressant-like effect was also evaluated. The immobility times in the tail suspension test (TST) and forced swimming test (FST) were reduced by (PhSe)(2) (5-100 mg/kg; oral route, p.o.). The antiimmobility effect of (PhSe)(2) (5 mg/kg, p.o.) in the TST was prevented by pretreatment of mice with L-arginine [a substrate for nitric oxide synthase (NOS)], methylene blue [an inhibitor of NO synthase and sGC] and sildenafil [a phosphodiesterase 5 inhibitor]. Furthermore, a sub-effective dose of (PhSe)(2) (0.1 mg/kg, p.o.) produced a synergistic antidepressant-like effect with N(G)-nitro-L-arginine [L-NNA; 0.3mg/kg, i.p. inhibitor of NOS], (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one [ODQ; 30 pmol/site i.c.v., a specific inhibitor of soluble guanylate cyclase (sGC)], fluoxetine and imipramine in the TST. (PhSe)(2) (50-100 mg/kg, p.o.) induced anxiolytic-like effect in the elevated plus-maze test and light/dark box. Together the results indicate that (PhSe)(2) elicited significant antidepressant-like and anxiolytic-like effects. The antidepressant-like action caused by (PhSe)(2) seems to involve an interaction with L-arginine-NO-cGMP pathway.     

Antidepressant-like effect of the organoselenium compound ebselen in mice: Evidence for the involvement of the monoaminergic system

Ebselen [2-phenyl-1,2-benzisoselenazol-3(2H)-one] is a seleno-organic compound which possesses a potent antioxidant activity and has been shown to exert neuroprotective effects in vitro and in vivo in a variety of pro-oxidative insults. The present study investigates a possible antidepressant activity of ebselen using two predictive tests for antidepressant activity in rodents: the forced swimming test and tail suspension test. Additionally, the mechanisms involved in the antidepressant-like effect of ebselen in mice were also assessed. Ebselen (10 mg/kg, s.c.) decreased the immobility time in the forced swimming test without accompanying changes in ambulation in the open-field test. In contrast, the administration of ebselen (10-30 mg/kg) did not produce any effect in the tail suspension test. The anti-immobility effect of ebselen (10 mg/kg, s.c.) was not prevented by pre-treatment of mice with p-chlorophenylalanine (PCPA, 100 mg/kg, i.p., an inhibitor of serotonin synthesis, 4 consecutive days), NAN-190 (0.5 mg/kg, i.p., a serotonin 5-HT_1A receptor antagonist) or ketanserin (5 mg/kg, i.p., a serotonin 5-HT_2A/2C receptor antagonist). On the other hand, the pre-treatment of mice with prazosin (1 mg/kg, i.p., an α₁-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α₂-adrenoceptor antagonist), SCH23390 (0.05 mg/kg, s.c., a dopamine D₁ receptor antagonist) or sulpiride (50 mg/kg, i.p., a dopamine D₂ receptor antagonist) completely blocked the antidepressant-like effect of ebselen (10 mg/kg, s.c.) in the forced swimming test. It may be concluded that ebselen produces an antidepressant-like effect in the forced swimming test that seems to be dependent on its interaction with the noradrenergic and dopaminergic systems, but not with the serotonergic system.     

绿萼梅提取物对小鼠的抗抑郁作用

目的：观察绿萼梅提取物对小鼠的抗抑郁作用。方法采用悬尾实验（ TFT）、强迫游泳（ FST）等体内药效评价方法观察绿萼梅醇提取物和水提取物对抑郁模型小鼠的治疗作用。结果绿萼梅醇提物能明显缩短小鼠悬尾和强迫游泳不动时间（ P＜0．05）,且对自主活动无影响（ P＞0．05）;而水提物对小鼠悬尾和强迫游泳不动时间无显著影响（ P＞0．05）。结论绿萼梅乙醇提取物具有抗小鼠抑郁作用。     

Analgesic Activity of Cistus laurifolius in Mice

The possible analgesic activity of Cistus laurifolius extracts has been evaluated by using tail flick and acetic acid-induced writhing tests in mice. The chloroform extract (500?mg/kg, i.p.) and the precipitated fraction (10, 30, 100?mg/kg, i.p.) obtained from C. laurifolius leaves showed significant analgesic activity on tail flick assay, while aqueous, ethanol and butanol extracts of the plant had no activity on the same test. Chloroform extract (500?mg/kg, i.p.) and precipitate fraction (30?mg/kg, i.p.) also inhibited number of writhings induced by acetic acid. These observations suggest that C. laurifolius leaves possess antinociceptive compound(s) which act through a central mechanism.     

GL-21抗抑郁的药效初探

目的：初步评价GL-21的抗抑郁药效,并探讨其可能的优势。方法：采用小鼠悬尾试验模型和小鼠强迫游泳试验模型初步评价抗抑郁效果。小鼠自发活动实验评价其兴奋作用。小鼠育亨宾毒性增强实验探讨其可能的作用机制。大鼠阴茎勃起实验,考察其对性功能的改善作用。结果：GL-21（1、2、4、8 mg·kg-1）可显著减少悬尾和强迫游泳试验的不动时间（P<0.01或P<0.05）,且不显著增加小鼠自发活动的总路程。GL-21（2、4、8 mg·kg-1）显著增强育亨宾毒性,增加小鼠死亡。剂量低至1.25 mg·kg-1（sc）可显著诱导大鼠阴茎勃起。结论：GL-21可能具有抗抑郁作用且改善性功能障碍。     

Neuropharmacology: Propylene Glycol Elicits Anxiolytic-like Responses to the Elevated Plus-maze in Male Mice

Propylene glycol is a common solvent often contained in injectable solutions of anxiolytics of low water-solubility, such as diazepam (Valium) and pentobarbital (Nembutal). Several studies have shown that propylene glycol can have an inhibitory effect on the central nervous system. This study, using ethanol for comparison, further examined whether propylene glycol has anti-anxiety properties. Use of the elevated plus-maze test with male mice revealed that propylene glycol at doses (27 or 41 mmol kg⁻¹, i.p.) which did not affect general activity, increased the number of entries into open arms and of head dips over open arm edges, indicative of an anxiolytic effect. In parallel, ethanol (14 and 27 mmol kg⁻¹, i.p.) caused an increase in the amount of time spent on open arms and number of entries into open arms, accompanied by reduction of returns into closed arms. These doses of ethanol had no significant effect on motor ability. The results suggest that propylene glycol can act as an anxiolytic agent and that its anxiolytic potency is weaker than that of ethanol. In addition to previous warnings about the pharmacological effects of propylene glycol, the findings of this study alert investigators to the anxiolytic properties of the compound when it is employed as a solvent in anxiety or anxiety-related studies.