Effects of acute and chronic administration of cannabis sativa and (-) delta9-trans-tetrahydrocannabinol on the behavior of rats in an open-field arena

Sedative-hypnotic effects of Boropinol-B on mice via activation of GABAA receptors

OBJECTIVES

Boropinol-B is a phenylpropanoid compound originally isolated from Boronia pinnata Sm. (Rutaceae). This study aimed to evaluate the sedative-hypnotic effects of Boropinol-B and explore the underlying mechanisms.

METHODS

Pentobarbital sodium-induced sleep mouse model and caffeine-induced insomnia mouse model were used to investigate the sedative effects of Boropinol-B. Pharmacokinetics profiles of Boropinol-B in rats were evaluated by high-performance liquid chromatography. The effects of Boropinol-B on the γ-aminobutyric acid (GABA)ergic system were investigated using ELISA assay and patch-clamp technique. Immunohistochemistry and immunofluorescence were carried out to assess the effects of Boropinol-B on sleep-related brain nucleus.

KEY FINDINGS

Boropinol-B showed significant sedative effects, including reduced sleep latency, increased sleep duration in pentobarbital sodium-treated mice and decreased locomotor activity in insomnia mice. Pharmacokinetics studies demonstrated that Boropinol-B had a rapid onset of action, a short half-life and no accumulation. It increased the GABA level in mice's brain, and promoted chloride ions influx mediated by the γ-aminobutyric acid type A (GABAA) receptors in neurons. Also, it increased the c-Fos positive ratio of GABAergic neurons in ventrolateral preoptic nucleus and decreased c-Fos expression in tuberomammillary nucleus.

CONCLUSION

Boropinol-B showed significant sedative-hypnotic effects in mice by activating the GABAA receptors and stimulating the sleep-related brain nucleus.

Biochemical and Pharmacological aspects of Ganoderma lucidum: Exponent from the in vivo and computational investigations

Ganoderma lucidum is known as lingzhi mushroom, which is said to have medicinal properties by the local residents. This research was focused to assess the antidepressant, anxiolytic, and sedative activities of the mentioned mushroom extracts by means of in vivo and in silico approaches. The antidepressant, anxiolytic, and sedative properties of the methanol extracts of G. lucidum (MEGL) were assessed using the forced swim test hole board, open field test, elevated plus maze, hole cross test, and thiopental sodium-induced sleeping time. The extracts revealed significant antidepressant, anxiolytic, and sedative activities in a dose-dependent manner. Rutin and quercetin were found to be the most effective enzyme inhibitors in the molecular docking study. According to the findings of in vivo and molecular docking study, it could be forecast that, the extract could have substantial antidepressant, anxiolytic, and sedative characteristics and deep molecular strategies on this extracts might create a target for the development of novel therapeutics. Further investigations are needed to appraise the molecular mechanisms implicated and isolate the bioactive components.

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Rutin and quercetin are reported in Ganoderma lucidum mushroom.

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The mushroom extracts possessed dose-dependent impacts on neural diseases.

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Elements of the Ganoderma lucidum yielded prominent binding affinity to the neural receptors.

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The mushroom extract is non-toxic evident from an acute toxicity study.

Evaluating the spectrum-effect profiling and pharmacokinetics of Tieshuang Anshen Prescription with better sedative-hypnotic effect based on Fe2+ than Hg2

Although Zhusha Anshen Pill (ZSASP) is a commonly used traditional prescription for insomnia, the safety of cinnabar in the formula has always been controversial since its initial application in medical fields. Here, we developed a new prescription, Tieshuang Anshen Prescription (TSASP), by improving ZSASP with Fe²⁺ instead of Hg²⁺. Besides, TSASP was further optimized by establishing and testing the HPLC fingerprint and its sedative-hypnotic effect of formulas with different compatibility ratios and performing correlation spectrum analysis. The safety of TSASP was also evaluated by HE staining of liver and kidney. In addition, a validated and robust UHPLC-MS/MS method was established to demonstrate the pharmacokinetic characteristics of berberine, palmatine, jatrorrhizine, ligustilide, catalpol, loganin, liquiritin and liquiritigenin after oral administration of TSASP. Our study originally provides a new non-toxic prescription, TSASP, with better sedative-hypnotic effect in comparison with ZSASP, revealing that Fe²⁺ could replace Hg²⁺ to eliminate its toxicity and play a sedative role. Meanwhile, we believe that our pharmacokinetics results may contribute valuable reference to both TSASP's specific mechanism of action and its further clinical efficacy and effectiveness research.

Loganin Exerts Sedative and Hypnotic Effects via Modulation of the Serotonergic System and GABAergic Neurons

Corni fructus, the fruit of Cornus officinalis Sieb. et Zucc., has been used as a tonic for the kidney in China for thousands of years. Loganin is one of the major constituents derived from Corni fructus. In this study, we revealed the sedative and hypnotic activity of loganin and investigated its mechanisms for the first time. Pentobarbital-induced sleep test and insomnia mice models [induced by caffeine and p-chlorophenylalanine (PCPA)] were used for the assessment of sedative and hypnotic effects of loganin. It was found that loganin (20–50 mg/kg) exerted sedative effect in normal mice. Loganin exhibited hypnotic effect by increasing sleep onset and sleep duration in pentobarbital-treated mice, recovering PCPA-induced insomnia and exerting synergistic hypnosis effect with 5-HTP. In addition, electroencephalograph (EEG) and electromyography (EMG) recordings of rats showed that loganin (35 mg/kg) prolonged the ratio of non-rapid eye movement (NREM) sleep and shortened wakefulness significantly, further immunohistochemistry showed that loganin (35 mg/kg) increased c-Fos expression in GABAergic neurons of rats in the ventrolateral preoptic nucleus (VLPO). The levels of norepinephrine (NE), dopamine (DA), serotonin (5-HT) and its metabolite were measured in the hippocampus, prefrontal cortex and striatum of mice, 1 h after loganin (35 mg/kg) treatment. 5-HT, 5-HIAA/5-HT, DA, and DOPAC were decreased significantly in the prefrontal cortex. In conclusion, these results indicated that loganin produced beneficial sedative and hypnotic activity, which might be mainly mediated by modification of the serotonergic system and GABAergic neurons.

Non-clinical acute and chronic toxicity evaluations of Cissus sicyoides L. (Vitaceae) hydroalcoholic leaf extract

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The Cissus sicyoides species has several pharmacological activities.

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The ethanolic extract from the leaves of Cissus caused few blood changes at the 40.5 mg/kg dose in the acute study.

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In the chronic study, EHA showed no toxic effects at the popular dose (4.5 mg/kg).

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Only the 13.5 mg/kg dose in the chronic trial showed blood changes.

Cissus sicyoides (Cs) has been traditionally used to treat diabetes and belongs to the family Vitaceae, and is known as “vegetable insulin". This study aimed to evaluate the acute and chronic non-clinical toxicity of hydroalcoholic extract from the leaves of Cissus sicyoides (EHA-Cs). The acute test was performed in Wistar rats, administering a single dose of 40.5 mg/kg. Behavioral parameters for pharmacological screening were observed to detect signs of Central Nervous System activity; consumption of daily food and water, and weight evaluation. After day 14, the animals were euthanized and blood samples were collected for laboratory analyses of hematological and biochemical parameters. The chronic tests were administered in doses of 4.5, 13.5 and 40.5 mg/kg. The same parameters were observed together with body temperature, glucose, exploration activity (test on the open field), and motor activity (diagnostic tests on the Rota-rod). For the group given the highest dosage during the study, histopathological examinations of vital organs were performed. For acute toxicity, there were no CNS level effects, changes in water and food consumption, or hematologic parameters. However, there was a significant decrease in weight gain for the treated females. Biochemical analyses of the treated animals presented increased levels of AST (aspartate aminotransferase) in females, uric acid levels in females and males, and amylase in males. In the chronic toxicity tests, water consumption was higher for females (at the dosages of 13.5 and 40.5 mg/kg) and for males (at 40.5 mg/kg). At the dosages of 4.5 and 13.5 mg/kg, feed consumption increased for females, while for males it decreased along with weight gain. Blood analysis presented an increase in albumin and changes in erythrocytes and hemoglobin for males (at the dose of 13.5 mg/kg). Glycemia in females (13.5 mg/kg dose) was significantly less, presenting only slight drops at the other doses. The changes were reversible in the satellite group. EHA-Cs revealed a relatively low toxicity profile (at the popular use dose), and only small changes in hematological and biochemical parameters at the dose of 13.5 mg/kg (3x the popular use dosage). In addition, EHA-Cs did not promote histological changes in vital organs such as the heart, lungs, liver and kidneys.

Motor and Behavioral Effects of Moringa oleifera Leaf Extract

Moringa oleifera is a medicinal plant widely used in many parts of the world for hypertension, pain and epilepsy. The aim of this study was to determine the effect of M. oleifera aqueous leaf extract on motor and behavioral activities of healthy mice. Male mice were randomly divided into a control group (given 0.9% NaCl orally) and three groups treated with the extract at doses of 100, 200, and 400 mg/kg/day for 14 consecutive days. Motor and behavioral activity were evaluated by quantifying motor activity, exploration (hole-board), neuro-muscular coordination (rota rod treadmill), pain (hot plate, cold-water tail flick, and acetic acid-induced abdominal constriction), and depression (forced swimming test, FST). Administration of M. oleifera extract had a significant and dose-dependent antinociceptive action in both thermal and chemical tests ( p < 0.05). The extract (400 mg/kg) caused a reduction in exploration activity and neuro-muscular coordination, and decreased the mobility time in the FST, suggesting an antidepressant-like action. Motor activity was not significantly affected by any of the doses used. The results suggest that the plant aqueous extract may have a dose-dependent central nervous system (CNS) depressant action.

Mechanism of TiO2 nanoparticle-induced neurotoxicity in zebrafish (Danio rerio)

Zebrafish (Danio rerio) has been used historically for evaluating the toxicity of environmental and aqueous toxicants, and there is an emerging literature reporting toxic effects of manufactured nanoparticles (NPs) in zebrafish embryos. Few researches, however, are focused on the neurotoxicity on adult zebrafish after subchronic exposure to TiO2 NPs. This study was designed to evaluate the morphological changes, alterations of neurochemical contents, and expressions of memory behavior-related genes in zebrafish brains caused by exposures to 5, 10, 20, and 40 μg/L TiO2 NPs for 45 consecutive days. Our data indicated that spatial recognition memory and levels of norepinephrine, dopamine, and 5-hydroxytryptamine were significantly decreased and NO levels were markedly elevated, and over proliferation of glial cells, neuron apoptosis, and TiO2 NP aggregation were observed after low dose exposures of TiO2 NPs. Furthermore, the low dose exposures of TiO2 NPs significantly activated expressions of C-fos, C-jun, and BDNF genes, and suppressed expressions of p38, NGF, CREB, NR1, NR2ab, and GluR2 genes. These findings imply that low dose exposures of TiO2 NPs may result in the brain damages in zebrafish, provide a developmental basis for evaluating the neurotoxicity of subchronic exposure, and raise the caution of aquatic application of TiO2 NPs.

A new furofuran lignan diglycoside and other secondary metabolites from the antidepressant extract of Castilleja tenuiflora Benth

Castilleja tenuiflora has been used for the treatment of several Central Nervous System (CNS) diseases. Herein we report the antidepressant activity of the methanol extract from the leaves of this medicinal plant. The oral administration of MeOH extract (500 mg/kg) induced a significant (p < 0.05) decrement of the immobility parameter on Forced Swimming Test (FST) and an increment in the latency and duration of the hypnosis, induced by administration of sodium pentobarbital (Pbi, 40 mg/kg, i.p.). Chemical analysis of this antidepressant extract allowed the isolation of (+)-piperitol-4-O-xylopyranosyl-(1→6)-O-glucopyranoside. This new furofuran lignan diglycoside was named tenuifloroside (1) and its complete chemical structure elucidation on the basis of 1D and 2D NMR spectra analysis of the natural compound 1 and its peracetylated derivative 1a is described. This compound was found together with two flavones—apigenin and luteolin 5-methyl ether—a phenylethanoid—verbascoside—and three iridoids—geniposide, caryoptoside and aucubin. All these compounds were purified by successive normal and reverse phase column chromatography. Tenuifloroside, caryoptoside and luteolin 5-methyl ether were isolated from Castilleja genus for the first time. These findings demonstrate that C. tenuiflora methanol extract has beneficial effect on depressive behaviors, and the knowledge of its chemical constitution allows us to propose a new standardized treatment for future investigations of this species in depressive illness.

TiO2 nanoparticles induced hippocampal neuroinflammation in mice

Titanium dioxide nanoparticles (TiO2 NPs) have been used in various medical and industrial areas. However, the impacts of these nanoparticles on neuroinflammation in the brain are poorly understood. In this study, mice were exposed to 2.5, 5, or 10 mg/kg body weight TiO2 NPs for 90 consecutive days, and the TLRs/TNF-α/NF-κB signaling pathway associated with the hippocampal neuroinflammation was investigated. Our findings showed titanium accumulation in the hippocampus, neuroinflammation and impairment of spatial memory in mice following exposure to TiO2 NPs. Furthermore, TiO2 NPs significantly activated the expression of Toll-like receptors (TLR2, TLR4), tumor necrosis factor-α, nucleic IκB kinase, NF-κB-inducible kinase, nucleic factor-κB, NF-κB2(p52), RelA(p65), and significantly suppressed the expression of IκB and interleukin-2. These findings suggest that neuroinflammation may be involved in TiO2 NP-induced alterations of cytokine expression in mouse hippocampus. Therefore, more attention should be focused on the application of TiO2 NPs in the food industry and their long-term exposure effects, especially in the human central nervous system.

Motor and Behavioral Changes in Mice With Cisplatin-Induced Acute Renal Failure

We have previously shown that chronic renal failure in rats induces changes in motor activity and behavior. Similar work on the possible effects of acute renal failure (ARF) induced by cisplatin (CP) is lacking. This is the subject matter of the current work. CP was injected intraperitoneally (i.p.) at a single dose of 20 mg/kg to induce a state of ARF, and three days later, its effects on motor activity, thermal and chemical nociceptive tests, neuromuscular coordination, pentobarbitone-sleeping time, exploration activity and two depression models were investigated. The platinum concentration in the kidneys and brains of mice was also measured. The occurrence of CP-induced ARF was ascertained by standard physiological, biochemical and histo-pathological methods. CP induced all the classical biochemical, physiological and histopathological signs of ARF. The average renal platinum concentration of CP-treated mice was 5.16 ppm, but there was no measurable concentration of platinum in the whole brains. CP treatment significantly decreased motor and exploration activities, and increased immobility time in depression models, suggesting a possible depression-like state. There was also a significant decrease in neuromuscular coordination in CP-treated mice. CP, given at a nephrotoxic dose, induced several adverse motor and behavioral alterations in mice. Further behavioral tests and molecular and biochemical investigations in the brains of mice with CP-induced ARF are warranted.

Effect of hydroalcoholic extract of Sphaeranthus indicus against experimentally induced anxiety, depression and convulsions in rodents

To investigate the effects of a hydroalcoholic extract of the Sphaeranthus indicus (SIE) against experimentally induced anxiety, depression and convulsions in rodents. The SIE (100, 200, 500 mg/kg, p.o.) was used in elevated plus maze, open field, forced swimming, and tail suspension tests in mice. The same doses were also used to evaluate its anticonvulsant effect on pentylenetetrazole (PTZ)-induced convulsions in mice and maximal electroshock (MES)-induced convulsions in rats. SIE was found to increase the number of entries and the time spent in the open arms of the maze at a dose of 100 mg/kg, p.o., indicating its anxiolytic activity. On the other hand, higher doses of SIE (200 and 500 mg/kg, p.o.) decreased open arm entries and time spent in the open arms of the maze in the elevated plus maze test indicating an absence of anxiolytic activity. However, this effect could have been related to a decrease in the locomotor activity of the mice and not to an anxiogenic effect, as indicated by the reduction in the total number of entries in the elevated plus maze. SIE also (at doses of 200 and 500 mg/kg, p.o.) decreased locomotor activity but did not affect emotional activity parameters in the open field test, suggesting a possible central nervous depressant activity. SIE also increased the immobility time in the forced swimming test at an oral dose of 500 mg/kg but did not significantly modify the activity in the tail suspension test. SIE protected rats against MES-induced convulsions and mice against PTZ-induced convulsions. Sphaeranthus indicus demonstrated anxiolytic, central nervous depressant, and anticonvulsant activities in rodents, thus supporting the folk medicinal use of this plant in nervous disorders.

Gene-expression changes in cerium chloride-induced injury of mouse hippocampus

Cerium is widely used in many aspects of modern society, including agriculture, industry and medicine. It has been demonstrated to enter the ecological environment, is then transferred to humans through food chains, and causes toxic actions in several organs including the brain of animals. However, the neurotoxic molecular mechanisms are not clearly understood. In this study, mice were exposed to 0.5, 1, and 2 mg/kg BW cerium chloride (CeCl(3)) for 90 consecutive days, and their learning and memory ability as well as hippocampal gene expression profile were investigated. Our findings suggested that exposure to CeCl(3) led to hippocampal lesions, apoptosis, oxidative stress and impairment of spatial recognition memory. Furthermore, microarray data showed marked alterations in the expression of 154 genes involved in learning and memory, immunity and inflammation, signal transduction, apoptosis and response to stress in the 2 mg/kg CeCl(3) exposed hippocampi. Specifically, the significant up-regulation of Axud1, Cdc37, and Ube2v1 caused severe apoptosis, and great suppression of Adcy8, Fos, and Slc5a7 expression led to impairment of mouse cognitive ability. Therefore, Axud1, Cdc37, Ube2v1, Adcy8, Fos, and Slc5a7 may be potential biomarkers of hippocampal toxicity caused by CeCl3 exposure.

Psychotropic activity of Argyreia speciosa roots in experimental animals

Argyreia speciosa (L.f.) Sweet (convolvulaceae) commonly known as Briddhadaraka is regarded as a “Rasayana” drug in the ayurvedic system of medicine to cure diseases of nervous system. In this study, hydroalcoholic root extract of A. speciosa was subjected to evaluate psychotropic effects in classical experimental models. Effect of the extract on spontaneous motor activity, pentobarbital-induced sleeping time, motor coordination, exploratory behavior, and apomorphine-induced stereotypy were investigated in mice. Effect of the extract on catalepsy and haloperidol-induced catalepsy were studied in rats. Preliminary phytochemical and acute toxicity screenings were also performed. The extract (100, 200, and 500 mg/kg, p.o.) significantly decreased spontaneous motor activity, exploratory behavior, and prolonged pentobarbital sleeping time in mice. The extract also remarkably attenuated the intensity of apomorphine-induced stereotypy but had no effect on motor coordination. The extract produced catalepsy and potentiated haloperidol-induced catalepsy in rats. These results provide evidence that the hydroalcoholic extract of A. speciosa roots may contain psychoactive substances that are sedative in nature with possible neuroleptic properties.

Differential responses to distinct psychotropic agents of selectively bred dominant and submissive animals

Dominance and submissiveness are two opposite poles of behavior representing important functional elements in the development of social interactions. We previously demonstrated the inheritability of these traits by selective breeding based upon the dominant-submissive relationships (DSR) food competition paradigm. Continued multigenerational behavioral selection of Sabra mice yielded animal populations with strong and stable features of dominance and submissiveness. We found that these animals react differentially to stressogenic triggers, antidepressants and mood stabilizing agents. The anxiolytic compound diazepam (1.5mg/kg, i.p.) reduced anxiety-like behavior of submissive animals, but showed anxiogenic effects among dominant animals. In the Forced Swim test, the antidepressant paroxetine (1, 3 and 10mg/kg, i.p.) markedly reduced immobility of submissive animals, demonstrating antidepressant-like effect. In contrast, when administered to dominant animals, paroxetine caused extreme (frenetic) activity. The mood stabilizer lithium (0.4%, p.o.) selectively influenced dominant mice, without affecting the behavior of submissive animals. In summary, we describe here two distinct animal populations possessing strong dominant and submissive phenotypes. We suggest that these populations hold potential as tools for studying the molecular basis and pharmacogenetics of dominant and submissive behavior.

Antinociceptive, antidiarrheal, and neuropharmacological activities of Barringtonia acutangula

CONTEXT

Barringtonia acutangula (L.) Gaertn. (Lecythidaceae) has been used in folk medicine in the treatment of arthralgia, chest pain, dysmenorrhea, inflammation, hemorrhoids, diarrhea, and also in psychological disorders.

OBJECTIVE

To investigate the antinociceptive, antidiarrheal, and neuropharmacological effect of the methanol extract of B. acutangula leaves and seeds in mice.

MATERIALS AND METHODS

The extracts (200 and 400 mg/kg; p.o.) were tested for antinociceptive activity by acetic acid-induced writhing, hot plate and tail immersion models; castor oil- and magnesium sulphate-induced diarrheal models were used to evaluate antidiarrheal activity whereas hole cross and open field models were employed for testing neuropharmacological activity.

RESULTS

Both extracts exhibited significant antinociceptive effect (p < 0.001) in acetic acid and heat induced pain models in a dose-dependent manner. The extracts prolonged the latency period to the thermal stimuli in both hot plate and tail immersion test. The extracts also showed significant inhibition of defecation (p < 0.001, 0.01) in both diarrheal models. Again, the spontaneous motor activity was decreased (p < 0.001) by the extracts in both hole cross and open field test.

DISCUSSION AND CONCLUSION

The results of this study suggest that the methanol extracts of B. acutangula leaves and seeds possess good antinociceptive, antidiarrheal, and central nervous system (CNS) depressant activities. This study validates the use of this plant in traditional medicine.

NHBA isolated from Gastrodia elata exerts sedative and hypnotic effects in sodium pentobarbital-treated mice

The rhizomes of Gastrodia elata have been used for the treatment of insomnia in oriental countries. N⁶-(4-hydroxybenzyl) adenine riboside (NHBA) was originally isolated from G. elata. For the first time we report a detailed study on the effects and mechanisms of NHBA on its sedative and hypnotic activity. Adenosine, an endogenous sleep factor, regulates sleep-wake cycle via interacting with adenosine A₁/A(2A) receptors. Using radioligand binding studies and cAMP accumulation assays, our results show that NHBA may be a functional ligand for the adenosine A₁ and A(2A) receptors. NHBA significantly decreases spontaneous locomotor activity and potentiates the hypnotic effect of sodium pentobarbital in mice. Sleep architecture analyses reveal that NHBA significantly decreases wakefulness time and increases NREM sleep times. However, NHBA does not affect the amount of REM sleep. Pretreatment with the adenosine A₁ receptor antagonist DPCPX or the A(2A) receptor antagonist SCH 58261 significantly reverses the increase in sleeping time induced by NHBA in sodium pentobarbital treated mice. Immunohistochemical studies show that NHBA increases c-Fos expression in GABAergic neurons of the ventrolateral preoptic area (VLPO), which suggests that NHBA activates the sleep center in the anterior hypothalamus. Altogether, these results indicate that NHBA produces significant sedative and hypnotic effects. Such effects might be mediated by the activation of adenosine A₁/A(2A) receptors and stimulation of the sleep center VLPO.

Evaluation of acute toxicity of a natural compound (+)-limonene epoxide and its anxiolytic-like action

The aim of the study is to determine the acute toxicity and anxiolytic-like effects of a mixture of cis and trans of (+)-limonene epoxide in animal models of anxiety. After acute treatment with (+)-limonene epoxide at doses of 25, 50 and 75 mg/kg (i.p.) no mortality was noted during 14 days of observation. In general, behavior, food and water consumption showed no significant changes. In open field test, (+)-limonene epoxide at doses of 25, 50 and 75 mg/kg, after intraperitoneal administration, significantly decreased the number of crossings, grooming and rearing (p<0.001). All these effects were reversed by the pre-treatment with flumazenil (25 mg/kg, i.p.), similar to those observed with diazepam used as a positive standard. In the elevated-plus-maze test, (+)-limonene epoxide increased the time of permanence and the number of entrances in the open arms. All these effects were reversed by flumazenil, an antagonist of benzodiazepine receptors. In addition, (+)-limonene epoxide (75 mg/kg) also produced a significant inhibition of the motor coordination (p<0.01), that was reversed by flumazenil. In conclusion, the present work evidenced sedative and anxiolytic-like effects of (+)-limonene epoxide, which might involve an action on benzodiazepine-type receptors. These results indicate that the properties of (+)-limonene epoxide should be more thoroughly examined in order to achieve newer tools for management and/or treatment of central nervous system diseases and anxiolytic-like effects. The LD50 obtained for the acute toxicity studies using intraperitoneal route of administration was 4.0 g/kg. These findings suggest that acute administration of the (+)-limonene epoxide exerts an anxiolytic-like effect on mice, and it could serve as a new approach for the treatment anxiety, since it practically does not produce toxic effects.

Evaluation of Behavioral and Pharmacological Effects of Hydroalcoholic Extract of Valeriana prionophylla Standl. from Guatemala

There are few studies on the pharmacological properties of Valeriana prionophylla Standl. (VP), known as "Valeriana del monte", and used in Mesoamerican folk medicine to treat sleep disorders. This study examines the pharmacological effects of the hydroalcoholic extract of the dry rhizome using the open field, rota rod, elevated plus-maze (EPM), forced swimming (FST), strychnine- and pentobarbital-induced sleeping time, PTZ-induced seizures, and the inhibitory avoidance tests. VP did not show any protective effect against PTZ-induced convulsions. In the EPM, exhibited an anxiolytic-like effect through the effective enhancement of the entries (38.5%) and time spent (44.7%) in the open arms, when compared with control group. Time spent and the numbers of entrances into the enclosed arms were decreased, similar to those effects observed with diazepam. In the FST, acute treatment with VP, produced a dose-dependent decrease in immobility time, similarly to imipramine. VP also produced a significant dose-dependent decrease in the latency of sleeping time, while producing an increase in total duration of sleep; influenced memory consolidation of the animals only at lower doses, unlike those that produced anti-depressant and anxiolytic effects. In summary, the results suggest that VP presents several psychopharmacological activities, including anxiolytic, antidepressant, and hypno-sedative effects.

Neuropharmacological activity of hydroalcoholic extract of leaves of Colocasia esculenta

CONTEXT

Although Colocasia esculenta Linn. (Araceae), commonly known as elephant ear (English), possesses diverse pharmacological activities in animals, little is known about its neuropharmacological activity.

OBJECTIVE

The present study evaluated the neuropharmacological activities of hydroalcoholic extract of leaves of Colocasia esculenta (HECE) using several experimental models.

MATERIALS AND METHODS

Adult Wistar albino rats were subjected to behavior despair and elevated plus maze (EPM) tests. Thiopental-induced sedation and rotarod tests were conducted on Swiss albino mice.

RESULTS AND DISCUSSION

The effects of HECE on anxiety, depression, thiopental-induced sleeping time, and rotarod performance were evaluated. The anxiolytic activity of HECE (100, 200, and 400 mg/kg) per os (p.o.) was characterized by increased time spent and number of entries in open arms in the EPM paradigm as compared to control group (p < 0.001). The HECE (100, 200, and 400 mg/kg, p.o.) showed dose-dependent significant reduction in duration of immobility (p < 0.01) in the behavior despair test. The HECE at the doses 50 and 100 mg/kg, i.p. was found to produce a significant reduction in motor coordination (p < 0.001) and prolongation of thiopental-induced sleeping time (p < 0.001). The phytochemical screening revealed the presence of flavonoids, β-sitosterol, and steroids.

CONCLUSIONS

The results of the study for the first time show that the plant possesses neuropharmacological activity, confirming the traditional claims. Future research should focus on the identification and the neurobehavioral activity of the constituents from this plant.

Evaluation of behavioral and pharmacological effects of Hedyosmum brasiliense and isolated sesquiterpene lactones in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Hedyosmum brasiliense Miq. (Chloranthaceae) is an essential Brazilian species largely found in the Atlantic Forest. It is popularly known as "cidrão" and in folk medicine, this aromatic species is widely used as a calmative/tranquilizer and to treat sleep disorders.

AIM OF THE STUDY

To examine the neurochemical properties of ethanol extract (EEHb), fractions and compounds of fresh leaves of Hedyosmum brasiliense and the antidepressant effect of the isolated sesquiterpene lactones podoandin and 13-hydroxy-8,9-dehydroshizukanolide.

MATERIALS, METHODS AND RESULTS

The effects of EEHb were demonstrated by the open field, elevated-plus-maze, forced swimming, pentobarbital-induced sleeping time, PTZ-induced seizure, and inhibitory avoidance tests. EEHb did not show a protective effect against PTZ-induced convulsions. In the plus-maze test, EEHb (100mg/kg, i.p.) exhibited an anxiolytic effect through the effective enhancement of the frequency and time spent in the open arms of the maze. Conversely, the time spent and the number of entrances to the closed arms were decreased. All these effects were also completely reversed by pre-treatment with flumazenil (2.5mg/kg, i.p./a benzodiazepine receptor agonist), similar to the results observed with diazepam used as a positive standard. In this test, the anxiolytic effect of EEHb was also totally blocked by pre-treatment with reserpine (2.0mg/kg, i.p.), a drug known to induce depletion of biogenic amines. In the forced swimming test, the treatment of EEHb (100mg/kg, i.p. or 100mg/kg, p.o.) given in acute and chronic form (10, 50 and 100mg/kg), produced a decrease in immobility time, similar to that of imipramine (10mg/kg, i.p.), the positive control. The dichloromethane and hexane fractions (100mg/kg, p.o.) also produced a decrease in immobility time. In addition, the two isolated compounds tested in a single dose (10mg/kg, i.p.), the antidepressant effect was observed only with the compound podoandin, which also caused a decrease in immobility time. EEHb (10-100mg/kg) a dose-dependent manner also caused a decrease in barbiturate sleeping time in mice, and in high doses (100mg/kg), did not interfere in memory consolidation.

CONCLUSIONS

The results suggest that EEHb presents psychopharmacological activities, including anxiolytic, antidepressant, and hypnotic effects.

An insight on the neuropharmacological activity of Telescopium telescopium--a mollusc from the Sunderban mangrove

The present study was carried out to evaluate the biological properties of the tissue extract of a marine snail Telescopium telescopium, collected from the coastal regions of West Bengal India. On extensive pharmacological screening, it was found that the biological extract of T. telescopium (TTE) produced significant central nervous system (CNS)-depressant activity as observed from the reduced spontaneous motility, potentiation of pentobarbitone induced sleeping time, hypothermia and respiratory depression with transient apnoea. The extract significantly decreased both residual curiosity and also muscle coordination. The fraction, obtained following saturation with 60-80% ammonium sulphate (80S), was also found to demonstrate predominant CNS-depressant activity. It was observed that both TTE and the 80S fraction significantly altered the brain noradrenaline and homovanillic acid levels without affecting the brain gamma amino butyric acid (GABA) concentration. Based on the present observations, it can be suggested that the CNS-depressant effects produced by TTE and 80S could be attributable to modified catecholamine metabolism in the brain.

Central nervous system depressant activity of an ethyl acetate extract from Ipomoea stans roots

Ipomoea stans Cav., popularly known as "tumbavaqueros", is a plant widely used in Mexico for the treatment of epileptic seizures and nervous disorders. This work researched the action of the ethyl acetate extract from the root of I. stans (IS-EAE) on the central nervous system (CNS). The administration of IS-EAE (2.5 and 5.0 mg/kg, i.p.) produced an anxiolytic effect in mice. This extract (20.0 and 40.0 mg/kg, i.p.) significantly reduced spontaneous motor activity. 2.5, 5.0, 10.0, and 20.0 mg/kg of IS-EAE protected mice against pentylenetetrazole-induced convulsions and increased the hypnotic effect induced by pentobarbital. The administration of IS-EAE was able to increase the release of GABA in brain cortex of mice. These results suggest that IS-EAE possess anxiolytic and anticonvulsant effects, and could have potential sedative effect, probably through a GABAergic system. The extract did not show antidepressant effects on mice exposed to forced swimming test.

Dominant-submissive behavior as models of mania and depression

This review examines the ways in which dominant-subordinate behavior in animals, as determined in laboratory studies, can be used to model depression and mania in humans. Affective disorders are mood illnesses with two opposite poles, melancholia (depression) and mania that are expressed to different degrees in affected individuals. Dominance and submissiveness are also two contrasting behavioral poles distributed as a continuum along an axis with less or more dominant or submissive animals. The premise of this article is that important elements of both mania and depression can be modeled in rats and mice based on observation of dominant and submissive behavior exhibited under well defined conditions. Studies from our own research, where dominance and submissiveness are defined in a competition test and measured as the relative success of two food-restricted rats to gain access to a feeder, have yielded a paradigm that we call the Dominant Submissive Relationship (DSR). This paradigm results in two models sensitive to drugs used to treat mood disorders. Specifically, drugs used to treat mania inhibit the dominant behavior of rats gaining access to food at the expense of an opponent (Reduction of Dominant Behavior Model or RDBM), whereas antidepressants counteract the behavior of rats losing such encounters; Reduction of Submissive Behavior Model (RSBM). The validation of these models, as well as their advantages and limitations, are discussed and compared with other animal paradigms that utilize animal social behavior to model human mood disturbances.

CNS pharmacological effects of the hydroalcoholic extract of Sida cordifolia L. leaves

Sida cordifolia L. (Malvaceae), known as "malva branca", is a plant used in the popular medicine for the treatment stomatits, of asthma and nasal congestion. This work researched the acute toxicity of Sida cordifolia and its action on the central nervous system (CNS) because no data in the literature have been found about of pharmacological activity of this plant in the CNS. The hydroalcoholic extract of Sida cordifolia leaves (HESc) was used and the psychopharmacology approach began with the determination of LD(50), where a low toxicity was observed in mice. Depressive activity on CNS was demonstrated by several alterations in mice's behavior in the pharmacological screening. In the motility test, the HESc showed significant reduction of spontaneous activity at a dose of 1000 mg/kg (i.p.) at 30 and 60 min. The same form the HESc also decreased the ambulation and rearing in open-field test at 30, 60 and 120 min at a dose of 1000 mg/kg (i.p.).

Anorectic and behavioural effects of chronicCissampelos sympodialistreatment in female and male rats

Male and female rats were treated daily for 13 weeks with an ethanol extract of Cissampelos sympodialis leaves (9, 45 and 225 mg[sol ]kg). The food consumption, body weight and behavioural effects in the open-field test were evaluated by weekly monitoring. The results showed that the extract chronic treatment in female rats (45 and 225 mg[sol ]kg) reduced significantly the food intake and the body weight, and produced several alterations in the open-field test. These findings indicate that repeated oral administration of the extract may produce a sex-dependent difference in anoretic and behavioural effects.

Neuropharmacological effects of the aqueous extract of Nauclea latifolia root bark in rats and mice

The present study evaluated the neuropharmacological effects of the aqueous extract of Nauclea latifolia root bark in rodents. Effects on the spontaneous motor activity (SMA), exploratory behaviour, pentobarbital sleeping time, apomorphine-induced stereotypic behaviour and motor coordination (rota-rod performance) were investigated. The extract (50-200 mg/kg p.o.) significantly (P<0.05) decreased the SMA and exploratory behaviour in mice and prolonged pentobarbital sleeping time in rats dose-dependently. The extract also remarkably attenuated the intensity of apomorphine-induced stereotypy dose-dependently in mice, but had no effect on motor coordination as determined by the performance on rota-rod. These results indicate the presence of psychoactive substances in the aqueous extract of the root bark of Nauclea latifolia.

Rapid tolerance to the intestinal prokinetic effect of cannabinoid CB1 receptor antagonist, SR 141716 (Rimonabant)

The cannabinoid CB(1) receptor antagonist, SR 141716 (Rimonabant), has been reported to stimulate, when acutely administered, intestinal motility in mice. The present study was aimed at determining whether tolerance develops to its repeated administration. Mice were treated twice a day for up to 8 consecutive days with 0, 3 and 5.6 mg/kg SR 141716 (i.p.). On days 1, 3, 5 and 8, separate groups of mice were treated intragastrically with a non-absorbable colored marker (carmine). The distance traveled by the head of the marker in the small intestine was recorded. On day 1, SR 141716 markedly activated intestinal peristalsis, but complete tolerance to this effect developed within the third day of treatment. The results may have some relevance to the proposed future clinical use of SR 141716.

Central nervous system activity of the methanol extract of Ficus platyphylla stem bark

The central nervous system (CNS) activity of the methanolic extract of Ficus platyphylla stem bark was studied on locomotor activity, pentobarbital sleeping time, exploratory behaviour, amphetamine-induced hyperactivity, apomorphine-induced stereotypy, active-avoidance and performance on tread mills (rota-rod), using mice and rats. The results revealed that the extract significantly reduced the locomotor and exploratory activities in mice, prolonged pentobarbital sleeping time in rats, attenuated amphetamine-induced hyperactivity and apomorphine-induced stereotypy in mice, dose-dependently. The extract significantly suppressed the active-avoidance response in rats, with no significant effect on motor co-ordination as determined by the performance on rota-rod. The results suggest that the extract may possess sedative principles with potential neuroleptic properties.

Cannabinoids and the gastrointestinal tract

The enteric nervous system of several species, including the mouse, rat, guinea pig and humans, contains cannabinoid CB1 receptors that depress gastrointestinal motility, mainly by inhibiting ongoing contractile transmitter release. Signs of this depressant effect are, in the whole organism, delayed gastric emptying and inhibition of the transit of non-absorbable markers through the small intestine and, in isolated strips of ileal tissue, inhibition of evoked acetylcholine release, peristalsis, and cholinergic and non-adrenergic non-cholinergic (NANC) contractions of longitudinal or circular smooth muscle. These are contractions evoked electrically or by agents that are thought to stimulate contractile transmitter release either in tissue taken from morphine pretreated animals (naloxone) or in unpretreated tissue (gamma-aminobutyric acid and 5-hydroxytryptamine). The inhibitory effects of cannabinoid receptor agonists on gastric emptying and intestinal transit are mediated to some extent by CB1 receptors in the brain as well as by enteric CB1 receptors. Gastric acid secretion is also inhibited in response to CB1 receptor activation, although the detailed underlying mechanism has yet to be elucidated. Cannabinoid receptor agonists delay gastric emptying in humans as well as in rodents and probably also inhibit human gastric acid secretion. Cannabinoid pretreatment induces tolerance to the inhibitory effects of cannabinoid receptor agonists on gastrointestinal motility. Findings that the CB1 selective antagonist/inverse agonist SR141716A produces in vivo and in vitro signs of increased motility of rodent small intestine probably reflect the presence in the enteric nervous system of a population of CB1 receptors that are precoupled to their effector mechanisms. SR141716A has been reported not to behave in this manner in the myenteric plexus-longitudinal muscle preparation (MPLM) of human ileum unless this has first been rendered cannabinoid tolerant. Nor has it been found to induce "withdrawal" contractions in cannabinoid tolerant guinea pig ileal MPLM. Further research is required to investigate the role both of endogenous cannabinoid receptor agonists and of non-CB1 cannabinoid receptors in the gastrointestinal tract. The extent to which the effects on gastrointestinal function of cannabinoid receptor agonists or antagonists/inverse agonists can be exploited therapeutically has yet to be investigated as has the extent to which these drugs can provoke unwanted effects in the gastrointestinal tract when used for other therapeutic purposes.

Changes in hippocampal morphology following chronic treatment with the synthetic cannabinoid WIN 55,212-2

Learning and memory are often correlated with cellular changes within the hippocampus, and drugs or environmental factors which affect learning and memory will thus often induce observable morphological changes in this structure. Like tetrahydrocannabinol (THC) itself, many synthetic cannabinoids such as the CB-1 receptor agonist WIN 55,212-2 will induce learning and memory changes. In the current study, we investigate whether or not these changes could be related to structural changes within the hippocampus. Adult male Sprague-Dawley rats were injected twice daily (12:00 and 0:00 h) subcutaneously with WIN 55,212-2 (2.0 mg/kg) in DMSO or DMSO for 21 days. On day 22, animals were perfused and stained immunochemically for the dendritic marker MAP-2, or with cresyl violet. Morphometric analysis showed dendritic rearrangement with increased staining of MAP-2 in CA3 and the lower blade of the dentate gyrus. However, a loss of staining was observed in CA1. Counting of cresyl violet stained sections showed an apparent increase in granule cell number in the lower blade of the dentate gyrus. This work shows the potential for cannabinoids to influence hippocampal morphology. The pattern of changes may be similar to that seen after ischemic or toxic damage, but may be opposite to changes seen in stress.

Central depressant effects of reticuline extracted from Ocotea duckei in rats and mice

Neuropharmacological studies were carried out with reticuline, a benzylisoquinoline alkaloid, isolated from Ocotea duckei Vattimo. It was found that reticuline (50-100 mg/kg i.p.) produced alteration of behaviour pattern, prolongation of pentobarbital-induced sleep, reduction in motor coordination and D-amphetamine-induced hypermotility and suppression of the conditioned avoidance response. These observations suggest that reticuline possesses potent central nervous system depressant action.

Reversible effects of acute and long-term administration of delta-9-tetrahydrocannabinol (THC) on memory in the rat

A study was designed to develop a measure of both acute and chronic effects of THC administration on memory in the rat. Errors in an 8-arm radial maze, before and after two delay intervals (5 s and 1 h, introduced between the fourth and the fifth arm choice), constituted the principal dependent measures. The first experiment involved testing the animals shortly after administration of 1.25 mg/kg THC. The drug did not affect performance in the pre-delay tests, although a significant effect was observed after the 5-s delay but not after 1-h delay. In the second experiment, 5 mg/kg THC or saline were administered 6 days/week for 90 days. Testing was conducted 18 h after each drug administration. During chronic administration the pre-delay performance did not differ between groups but the post-delay performance of the THC group deteriorated in a gradual manner, relative to their controls, in both the 5-s and 1-h delay conditions. After discontinuation of drug administration, the differences between groups reversed only after 30 days. The results provided evidence that both acute and chronic administration of THC affected working-memory in the radial arm maze test, although it did not interfere with the general cues of the task (reference memory). Chronic drug effects on memory were reversible after prolonged abstinence. Thus, the 8-arm radial maze task proved to be a useful measure of THC effects on memory and could be further used to investigate more thoroughly the mechanisms involved in such drug effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acute administration of delta 1-tetrahydrocannabinol on beta-endorphin levels in plasma and brain tissue of the rat

Acute treatment with delta 1-tetrahydrocannabinol (delta 1-THC) elevated the concentration of beta-endorphin-like immunoreactivity (beta-ELIR) in plasma and in the hypothalamus, but not in the hippocampus of rats habituated to the injection procedure. These effects were not obtained with the psychotropically inert analog of delta 1-THC, cannabidiol. In animals that had not been habituated to the injection procedure, placebo treatment induced a decrease in hippocampal beta-ELIR.

Pharmacology of some synthetic tetrahydrocannabinols

DMHP (1-hydroxy-3-1', 2'-dimethylheptyl-6,6,9-trimethyl 7,8,9,10-tetrahydro-6-dibenzopyran or in brief dimethyl heptyl pyran, EA 1476) is a synthetic analog of delta 9-tetrahydrocannabinol (delta 9-THC). Both DMHP and its acetate, DMHPA (EA 2233) produce varying degrees of physical and mental incapacitation. Both compounds elicit orthostatic hypotension at dose levels far below those required to produce mild mental incapacitation. Compared with delta 9-THC, DMHP has clearly more potent and prolonged hypotensive action, but much less psychological effect. The potencies of DMHP and DMHPA are more or less similar, but the acetate derivative is more stable against the degrading effects of light and air. Like DMHP, DMHPA consists of eight isomers which vary in their potency. Accordingly, depending on the proportion of the isomers, the racemic mixtures show variability in their potencies. The isomers 2 and 4 have been shown to be more potent than the other isomers.

delta 1-Tetrahydrocannabinol-induced circling behavior in rats: a possible measure of psychotomimetic activity?

Relatively high dosages of delta 1-tetrahydrocannabinol (delta 1-THC) markedly suppressed almost all normally occurring behavioral elements in rats as observed in both a small and a large open field. This effect persisted following repeated treatment and testing for 3 consecutive days. The psychotropically inert but related compound cannabidiol (CBD) did not suppress behavior, but in contrast had a mild activating effect. Both compounds decreased defecation during the test procedure. In addition, delta 1-THC, but not CBD, induced a bizarre circling and turning response, that was evident over all 3 test days and occurred even when the rats were deeply sedated. It is suggested that an analysis of this phenomenon may be useful in measuring the psychotomimetic action of delta 1-THC and similar compounds in rats.

Does tolerance develop to the activating, as well as the depressant, effects of ethanol?

Genetically determined differences were demonstrated in the response of mice to low doses of ethanol. Ethanol (1.35 g/kg) produced an increase in locomotion in DBA/2 and BALB/c mice, but did not alter the locomotor activity of C57B1/6 mice. Chronic administration of ethanol produced tolerance to the sedative/hypnotic effects of high doses of ethanol in DBA/2 and BALB/c mice, but the equivalent chronic ethanol administration paradigm produced no tolerance to the activating effects of ethanol in these animals. C57B1/6 mice became tolerant to the hypnotic effects of ethanol, but no change in the behavior of these mice, given a low dose of ethanol, was noted after the mice were withdrawn from chronic feeding with ethanol-containing diets. The results indicate the presence of different mechanisms for tolerance development to the activating and depressant effects of ethanol, and indicate that strain-dependent differences in the activating effects of ethanol are not determined by an animal's greater sensitivity to the sedating effects of this drug.

The excitatory component of ethanol in mice: a chronic study

The effects of chronic administration of initially depressant, ineffective and excitatory doses of ethanol on the locomotor activity of mice was studied. The results showed that (1) an excitatory effect of ethanol is observed after tolerance develops to its depressant action; (2) the effect induced by an initially excitatory dose of ethanol became more pronounced with chronic exposure to the drug; and (3) tolerance to the excitatory effect was not reached after 60 days of ethanol treatment.

Tolerance to the effects of delta9-THC on shuttle-box performance and body temperature

Two groups of rats were trained in a shuttle-box and received delta9-tetrahydrocannabinol (delta9-THC), either before or after being tested. The drug-before group showed tolerance--within 3-6 sessions--to the response-inhibiting effect of THC. The drug-after animals appeared also to be tolerant when they received delta9-THC before being tested. It is concluded that the tolerance to this effect probably is not learned, but has a physiological base. This is corroborated by the finding that during the same study all the animals developed tolerance to the hypothermic effect of delta9-THC.