Because of the increasing number of emerging studies using MGE cells prepared by different methods and showing discrepant results, the aim of the present study was to compare the two preparations of MGE cells and investigate the long-lasting effects of the transplantation of either freshly dissociated or neurosphere dissociated MGE-derived cells into the neonate brain of male rats on postnatal (PN) day 2–3 on the anxiety behavior of these animals when tested at early adulthood (PN 62–63) using the Elevated Plus Maze (EPM). The EPM is one of the most widely used tests in contemporary preclinical research on anxiety, and is based on an innate fear that rodents have for open and elevated spaces . When in the EPM, rats tend to avoid the open arms and clearly prefer the enclosed arms. The avoidance of the open arms occurs primarily because the open arms pre- vent the rat from engaging in thigmotaxic behavior . The ratio of open-arm to total arm entries has been used as an index of anxiety . Often, the percentage of time spent in the open arms is also reported. Anxiolytic drugs increase the number of entries into and the total time spent in the open arms, whereas anxiogenic agents do the opposite [21,22]. Our data suggest a long-term anxiolyticeffect following transplantation of freshly dis- sociated MGE cells, but not of cells expanded as neuro- spheres. We propose that the fresh cells were able to reinforce the inhibitory function of the GABAergic neur- onal circuitry related to anxiety-like behavior in rats.
It has been shown that a prior forced exposure to one of the open arms of the maze, by shortening latencies to withdrawal from the open arm during the test, improves the escape task as a behavioral index of panic. The effects of muscimol in the elevated T-maze were compared to those caused by this GABA agonist in the avoidance reaction generated in the light/dark transition test. This defensive behavior has also been associated with GAD. In the elevated T-maze, intra-BLA injection of muscimol impaired inhibitory avoidance (control: 187.70 ± 14.90 s, muscimol: 37.10 ± 2.63 s), indicating an anxiolyticeffect, without interfering with escape performance. The drug also showed an anxiolyticeffect in the light/dark transition test as indicated by the increase in the time spent in the lighted compartment (control: 23.50 ± 2.45 s, muscimol: 47.30 ± 4.48 s). The present findings point to involvement of the BLA in the modulation of defensive responses that have been associated with GAD.
After treatment, the animal was placed at the center of the plus maze with its nose in the direction of one of the closed arms and observed for 5 min, according to the following pa- rameters: number of entries in the open and closed arms and time of permanence in each of them. The time of permanence measures the time spent by the animal in the open and closed arms. Anxiolytic compounds reduce the animal’s aversion to the open arms and promote the exploration thereof. The pa- rameters observed were percentages of entries into open arms (PEOA), number of entries in the open arms (NEOA), time of permanence in open arms (TPOA), and percentage of time of permanence in the open arms (PTOA).
Previous studies have shown that the depletion of Mg leads to an increase in depression and anxiety-related behaviors in mice, while Mg supplementation lessens the anxiety-related behaviors of mice (2, 28). Mg has been proved to modulate both glutamatergic neurotransmission (via a voltage-dependent block of NMDA receptors) and GABAergic neuro- transmission (5-7). It has been demonstrated that increasing glutamate and GABA levels in brain respectively increases and decreases anxiety in animals (2, 23,30). In addition, Mg has been proved to control the activity of the HPA axis, which is considered to be the main stress response system (3). Some studies demonstrated that, since Mg can block this receptor, the blockers of NMDA induce anxiolyticeffect (31). It was also noted that the conventional forms of MgO had no effect on anxiety-related behaviors. In fact MgO NP reduced anxiety, while conventional MgO was ineffective. This may be related to the nanoparticles properties and their ability to affect many neurochemical pathways with equal dose (32, 33). Increased surface area of nanoparticles can increase reactive groups more than their conventional form and increase their reactivity (32, 33). Following the injection of nanoparticles and conventional forms of MgO supplements during training made no changes in the anxiolyticeffect of exercise activity (Figure 3A and B).
Anxiolytic compounds reduce the natural animal aversion to the open arms and promote the exploration thereof in the elevated-plus maze test. On the other hand, the forced or voluntary passages of the animal into the closed arms of the EPM are associated with hormonal and behavioral changes indicative of increased anxiety (Hogg, 1996; Santos et al., 2012). Montgomery (1955) reported that rodents consistently spend greater time in the closed arms when placed in mazes comprising of open and closed arms. Avoidance of the open arm portrays a manifestation of fear and anxiety. Based on these assertions, the elevated plus maze test is a reliable means of identifying selective anxiolyticeffect of drugs. Handley & Mithani (1984) further demonstrated that rodents avoid the open arms while also reporting that open arm avoidance is reduced by diazepam (anxiolytic agent). T. occidentalis at the dose of 100 mg/kg increased the number of entries into the open arms (90%) without any signiicant effect on cumulative time spent in the open and closed arms and in the central Treatments Dose (mg/kg) No. of squares
The crude hexane extract of Tillia americana var mexicana at 10 and 30 mg/kg i.p and some pooled fractions at the same doses were observed to potentiate sodium pentobarbital-induced sleeping time and caused a significant increase in the time spent at the open-arm sides in the plus-maze test. A reduction in the exploratory behavioural pattern was reported to manifest as ambulatory activity . Dolichandrone falcata seem (Bignoniaceae) is a deciduous tree that thrives well in India. 400 mg/kg of the ethyl acetate extract of the stem bark was shown to produce a significantly high anxiolyticeffect in a dose dependent manner by increasing the time spent on and the number of entries into the open arms of the elevated plus-maze and by decreasing the number of marbles buried by mice in marble burying test .
that a single cocaine injection induces anx- iogenic-like effects in handling-habituated mice, while repeated injections of the drug did not alter the indices of anxiety as meas- ured in the elevated plus-maze. This could be the case for our mice on special diets that were handled every two or three days. How- ever, our animals showed the opposite effect with cocaine - an “anxiolytic” effect in mice on a high-fat diet or receiving leptin spent more time in the open arms. Also important to note is that the anxiolyticeffect of leptin became more evident in those animals ex- posed to the highest dose of cocaine, i.e., lower values in mice treated only with leptin, and the percent time spent in the open arms increasing progressively with increasing leptin doses. This effect has been rarely reported by other laboratories, but has been seen with Wistar rats in our laboratory (Loebens M and Barros HMT, unpublished data) on other occasions. The explanation for this effect still needs to be determined. We believe that cocaine decreases risk evalu- ation by the animals and induces open-arm entries in spite of the risk involved, due to the impulsivity-induced effect. Leptin per se does not increase the percentage of entries into the open arms, but when mice received increasing doses of cocaine, this behavior became more evident, reaching peak values at 20 µg/kg leptin.
Elevated Plus Maze Test Oral administration of 1.0 g/kg of EOP produced a significant (p#0.05, ANOVA fol- lowed by Duncan’s test) increase in permanence in the open arms of the maze (Fig. 3), suggesting an anxiolyticeffect of this preparation. However, treatment with the extract and fractions obtained from leaves (HE, HF, DF and AF) did not show any differences from those of the control group (Fig. 4). In both experimental sessions, animals treated with Di- azepam (DZP – 1.2 mg/kg, i.p.) spent more time in the open arms of the maze.
The hole-board test, developed by Boissier & Simon (1962, 1964), has gained popularity as model of anxiety, offering “a simple method for measuring the response of an animal to an unfamiliar environment, with advantages that several behaviors can be readily observed and quantiied in this test” (Takeda et al., 1998; Silva & Elisabetsky, 2001). Drugs as benzodiazepines signiicantly increase the number of head-dips in the hole-board test (Takeda et al., 1998). In our study, EER (3.9 and 7.8 mg/ kg, i.p.) increased head-dip counts and increased head-dip duration without changing locomotion in the hole-board test. Additionally, EER increased visits numbers to board compared with control group. These results suggest that EER has a signiicant anxiolyticeffect in this paradigm.
(aerobic exercise, clomipramine and placebo) for 10 weeks of intervention on the severity of PD with or without agoraphobia. Using the “Agoraphobia and Panic Scale”, and the “Hamilton Anxiety Scale”, the results showed that clomipramine was always superior to placebo and exercise conditions. Despite the superiority of clomipramine, aerobic exercise was superior to placebo condition. Thus, aerobic exercise alone may have some anxiolyticeffect in PD patients in this study.
The aims of the present study were (1) to evaluate the sedative and anxiolytic effects of the HE and essential oils from K. odoratissima and (2) to determine the main constituents of the essential oil fraction. To assess the anxiolytic effects of this Iranian plant, an EPM was used to assess anxiety. In agreement with previously published reports, diazepam increased the percentage of time spent and number of entries into the open arms, 15-17 which confirmed the validity of the EPM model and the anxiolytic activity of diazepam. 18 In contrast to diazepam, the total HE and essential oils from K. odoratissima did not produce significant increases in the EPM parameters, thereby indicating a lack of anxiolytic-like effects. Several explana- tions can be given for this lack of an anxiolyticeffect. First, it is possible that the plant does not contain any bioactive, detectable constituent to produce anxiolytic effects. Therefore, the calming effect of the plant reported after consuming the dried aerial parts could be due to reduced locomotor activity, which we witnessed in this study.
(5) content. To assess the anxiolytic-like response, methanol extracts of Tilia inflorescences (from 10 to 300 mg/kg, i.p.) were tested in mice using open-field, hole-board and plus-maze tests, as well as sodium pentobarbital-induced hypnosis. No difference in the neuropharmacological activity was observed between methanol extracts of Mexican Tilia collected in three different places. Nevertheless, quercetin and kaempferol aglycons were tested and showed anxiolytic-like response, therefore the authors suggest that the pharmacological effect of Tilia inflorescences involves quercetin and kaempferol (10 mg/kg, i.p.), but is independent of the kind of glycosides present in the samples (Aguirre-Hernández et al., 2010). In contrast, other research group also working with Tilia americana subsp. mexicana var. mexicana and evaluated the anxiolyticeffect of four extracts of the combined bracts and flowers, successively macerated with n-hexane, ethylacetate, methanol, as well as an ethanol-water extract. These authors reported that hexane, ethyl acetate and aqueous extracts (p.o.), displayed no anxiolyticeffect, evaluated by EPM test in mice; while the methanol extract at identical doses (25-200 mg/kg) showed anxiolyticeffect without motor activity alteration. The methanol extract was subjected to a bioassay-guided fractionation, which afforded a rich flavonoid mixture with anxiolytic activity, identifying tiliroside (6) as the major component; however, this compound was not isolated and tested (Herrera-Ruiz et al., 2008). It is noteworthy that other plant species with the popular name “tila” are also used in México for “nervios“, but they have been identified as species from the genus Ternstroemia. In the case of Ternstroemia pringlei the methanol and aqueous extracts from the fruits elicited sedative, but not anxiolytic, activity (Balderas et al., 2008; Lozada-Lechuga et al., 2010).
Several studies have investigated the effects of omega- 3 fatty acids in animal models of anxiety (Table 1). Most of the rodent studies involved long-term diet supplements with DHA or a combination of EPA and DHA. Carrie´ et al. used a DHA-supplemented diet in mice previously fed with a semisynthetic balanced diet or a diet deficient in alpha-linolenic acid (ALA) (another type of omega-3 fatty acid) until the age of 8 months. The supplemented diet showed anxiolytic effects, regardless of the previous diet condition, and restored water maze performance, which had been impaired in the ALA deficient diet group. 72 Jasˇarevic´ et al. treated female mice for three generations with an omega-6/omega-3 supplemented diet and found that the male offspring of the third generation showed decreased anxiety-like behavior. 78 Rat diets supplemen- ted with different combinations of PUFAs counteracted the anxiogenic effects of intracerebroventricular adminis- tered IL-1 beta 73,74 and restraint stress. 75,77 The anxiolyticeffect of omega-3 supplementation has also been demon- strated in adult male grey mouse lemurs (Microcebus murinus), a nocturnal Malagasy prosimian primate. 76,79
Anxiolytic plants may interact with either glutamic acid decarboxylase (GAD) or GABA transaminase (GABA-T) and ultimately inluence brain GABA levels and neurotransmission (Awad et al., 2007). Flavonoids have recently increased in importance because they have been identiied as a new type of ligand with in vivo anxiolytic properties. The lavones chrysin and apigenin, obtained from medicinal plants, have shown an anxiolyticeffect in rodents exposed to behavioral tests. Apparently, these compounds modulate the γ-aminobutyric acid (GABA) ergic system to produce the biological effect (Herrera-Ruiz et al., 2008). However, only a low content of lavonoids was found in this hydroethanolic extract.
This study suggests that the administration of a liposomal formula- tion containing nimodipine at the doses of 0.1, 1 and 10 mg/kg did not produce sedation and muscle relaxation in mice, showing anxiolytic- like activity in the open ﬁeld, the light and dark and the elevated plus- maze test. The results of the treatment with NMD-Lipo were signiﬁcant- ly better than the rodents treated with non encapsulated nimodipine, suggesting that the liposomes promoted a drug controlled release by in- creasing its bioavailability and consequently its effect. The decrease in the anxiolyticeffect of NMP-Lipo in animals pretreated with ﬂumazenil suggests that the formulation acts on benzodiazepine receptors.
Conversely, the lowest acute dose of CBD was able to increase social interaction in Wistar rats, an effect that can be related to an anxiolytic property of this drug. In this sense, anxiolytic properties of CBD have been reported in several studies with rodents using different paradigms such as conditioned fear (Resstel et al., 2006), elevated plus-maze (Campos and Guimaraes, 2008; Guimaraes et al., 1990, 1994; Moreira et al., 2009), prey vs predator paradigm (Uribe-Mariño et al., 2012) and Vogel conﬂict test (Moreira et al., 2006). The anxiolyticeffect of CBD was also evaluated in humans. Simulated public speaking is a test that can induce anxiety and is sensitive to the effects of anxiolytic drugs. In this test, CBD had an anxiolyticeffect similar to that of diazepam and ipsapirone in healthy subjects (Zuardi et al., 1993). In the same way, CBD had an anxiolyticeffect on patients with generalized social anxiety disorder submitted to simulated public speaking (Bergamaschi et al., 2011), an effect that seems to be mediated by activation of limbic and paralimbic brain regions (Crippa et al., 2011).
Studies on the effects of buspirone also present controversial results regarding the locomotor activity and anxiety in the plus-maze. Majercsik and collaborators (2003) reported that a single administration of 6 mg/kg or 10 mg/kg of BUS, 30 minutes before the exposure to the maze, caused a decrease in locomotor activity, %TOA and percent of risk assessment in rodents, while the dose of 3 mg/kg, in the same protocol, did not alter locomotion or exertes any effects on %TOA and risk assessment. On the other hand, Griebel and collaborators (1997) reported that 1 mg/Kg, 30 minutes before exposure to the maze, had no effect in %TOA, but decreased risk assessment. Thus, as noticed in our data, it is evident that lower doses of BUS did not alter locomotor activity but exerted an anxiolyticeffect in rodents, even under stress, since the Cont- BUS and Str-BUS groups showed no change in locomotor activity alteration bret decreased the frequency of PHD and SAP. Our results showed that the groups administered with BUS, irrespective of stress condition, learned the task, but did not retriev the memory. Further, this deficit appeared to be larger than the deficit caused by the restraint stress in this phase of memory.
Tilia cordata Mill. (Tiliaceae) has been used in folk medicine, primarily as a non-narcotic sedative for sleep disorders or anxiety. The anxiolyticeffect of Tilia species, such as T. americana var. Mexicana, has been attributed to the presence of tiliroside (Anesini et al., 1999; Perez-Ortega et al., 2008). Phytochemical studies have demonstrated that Tilia species possess hydrocarbons, esters, aliphatic acids (Fitsiou et al., 2007), terpenoids, quercetin and kaempferol derivatives (Pietta et al., 1994), phenolic compounds, condensed tannins (Behrens et al., 2003) and a coumarin scopoletin (Arcos et al., 2006). Tilia americana var. Mexicana has several lavonoids such as rutin, hyperoside, quercitrin and
Experiment 2 – Effect of isopregnanolone on the rapid tolerance to the anxiolyticeffect of ethanol. On day 1 of the experiment, 60 mice (three groups of 20) were pretreated with saline, and another 60 (also in three groups of 20) were pretreated with isopregnanolone (0.05, 0.10 or 0.20 mg/kg, respectively). After 30 minutes, each group was divided into two subgroups of 10 mice each, and the mice in one of each pair of subgroups received 1.5 g/kg of ethanol, whereas those in the corresponding subgroups received 1.5 g/kg of saline. The animals were then returned to their home cages. On day 2, all of the animals were treated with a dose of 1.5 g/kg of ethanol and the anxiolytic response was evaluated. The 1.5 g/kg dose of ethanol was chosen because it produced more evident tolerance (Figure 1).
ABSTRACT: Erythrina speciosa Andrews, Fabaceae, is used in the South of Brazil as sedative and tranquilizers. In this study, behavioral effects of aqueous (AE) and dichloromethane (DCM) extracts of E. speciosa leaves were evaluated in male mice, as well as their lethal dose 50% (LD50). The extracts were administered by gavage in doses ranging from 50 to 400 mg/kg 1 h before the behavioral tests. AE decreased ambulation (50, 100 and 400 mg/kg) and rearing (50 and 400 mg/kg) in the open-field but did not influence elevated plus maze, rotarod and pentobarbital-induced sleep tests. No behavioral effects were observed after DCM administration. LD50 for both extracts were higher than 2000 mg/kg. The results showed that AE and DCM extracts of E. speciosa leaves do not produce anxiolyticeffect in the elevated plus maze nor seems to depress the Central Nervous System. However, since serotonergic mechanisms may be involved in the pharmacological action of Erythrina plants and the elevated plus maze test is not adequate to evaluate serotonergic drugs, our results do not invalidate the use of this plant in folk medicine but suggest that the mechanism involved in a possible central action of Erythrina needs to be clarified.