Effect of Psilocybin and Ketamine on Brain Neurotransmitters, Glutamate Receptors, DNA and Rat Behavior.

Clinical studies provide evidence that ketamine and psilocybin could be used as fast-acting antidepressants, though their mechanisms and toxicity are still not fully understood. To address this issue, we have examined the effect of a single administration of ketamine and psilocybin on the extracellular levels of neurotransmitters in the rat frontal cortex and reticular nucleus of the thalamus using microdialysis. The genotoxic effect and density of glutamate receptor proteins was measured with comet assay and Western blot, respectively. An open field test, light-dark box test and forced swim test were conducted to examine rat behavior 24 h after drug administration. Ketamine (10 mg/kg) and psilocybin (2 and 10 mg/kg) increased dopamine, serotonin, glutamate and GABA extracellular levels in the frontal cortex, while psilocybin also increased GABA in the reticular nucleus of the thalamus. Oxidative DNA damage due to psilocybin was observed in the frontal cortex and from both drugs in the hippocampus. NR2A subunit levels were increased after psilocybin (10 mg/kg). Behavioral tests showed no antidepressant or anxiolytic effects, and only ketamine suppressed rat locomotor activity. The observed changes in neurotransmission might lead to genotoxicity and increased NR2A levels, while not markedly affecting animal behavior.

Anxiolytic-like and antidepressant-like effects of ethanol extract of Terminalia chebula in mice.

Terminalia chebula (T.chebula) fruit is referred as "King of Medicines" in Tibet and is listed as a key plant in "Ayurvedic Materia Medica" due to its diverse pharmacological activity. The present study was aimed to investigate the comorbid antidepressant-like and anxiolytic-like effects of ethanol extract from T.chebula fruit using experimental behavioral tests in mice. In addition, the study explored the effects of extract on monoamine oxidase -A (MAO-A) levels in mouse brain. Two doses of the T.chebula extract (100 or 200 mg/kg, p.o.) were treated continuously for fifteen days to mice. Regarding antidepressant-like effects, the treatment of T.chebula extract at both dose (100 or 200 mg/kg, p.o.) levels resulted with significant (p < 0.001) reduction in duration of immobility time and increase in swimming time as compared to control group in forced swimming test. Moreover, both doses declined the duration of immobility time in the tail suspension test and increased the number of crossing in the center area using open-field test. Additionally, the dose 200 mg/kg treatment showed a significant reduction (p < 0.05) in MAO-A activity in mouse brain. For anxiolytic activity, both doses significantly (p < 0.001) improved the time spent in open arm and the number of head dips in elevated plus maze test. The higher duration of time spent in light chamber and higher number of crossing between the light and dark chambers by extract treatment in light-dark box test also supported the anxiolytic behavior. The obtained results supported the antidepressant-like and anxiolytic-like effects of ethanol extract of T.chebula in mice.

Assessment of Antidepressant-like, Anxiolytic Effects and Impact on Memory of Pimpinella anisum L. Total Extract on Swiss Albino Mice.

Mental disorders are psychological symptoms that impact multiple areas of an individual's life. Depression and anxiety are chronic illnesses described as the most prevalent stress-related mood disorders that cause injury and early death. In Morocco, Anise "Pimpinella anisum L." is one of the most traditionally used condiment plants, which has long been used to cure various illnesses and in phytotherapy. The present study was designed to investigate the antidepressant, anxiolytic, and memory impact of the total extract of Pimpinella anisum (PATE) at the doses of 100 and 200 mg/kg, using the Forced Swimming Test (FST), Tail Suspension Test (TST), Open Field Test (OFT), and Light-Dark Box Test (LDBT) as an experimental paradigm of anxiety and depression, and Novel Object Recognition Test (NORT) and the Morris Water Maze Test (MWMT) as memory tests on Swiss albino mice. The tests were carried out on the 1st, 7th, 14th, and the 21st days of the study, and the extract groups were compared with normal controls and positive controls (receiving bromazepam and paroxetine at the doses of 1 mg/kg and 11.5 mg/kg for anxiety and depression, respectively). The daily oral gavage of the mice by the PATE induced a significant anxiolytic and antidepressant-like effect by shortening immobility time and decreasing downtime in the different tests. PATE at both doses was shown to have no impact on memory following the NORT and MWM tests. Different compounds, such as gallic acid, catechin, chlorogenic acid, caffeic acid, oleuropein, p-coumaric acid, trans-4-hydroxy-3-methoxycinnamic acid, myricetin, and quercetin, were identified during the phytochemical analysis carried out using HPLC analysis. This research supports and promotes the extract's traditional use, suggesting its use as a phytomedicine against depression and anxiety, and calls for further research to clarify its mode of action.

Inhalation Administration of the Bicyclic Ethers 1,8- and 1,4-cineole Prevent Anxiety and Depressive-Like Behaviours in Mice.

The anxiolytic and antidepressant-like activities of the naturally occurring monoterpene 1,8-cineole and its structural isomer 1,4-cineole were evaluated in mice via inhalation administration at doses ranging from 4 × 10-6 to 4 × 10-1 mg per 400 µL of triethyl citrate. Mice were tested for anxiety-like behaviours by using the light-dark box test (LDB) and marble-burying test (MBT) and for depression-like symptoms by using the forced swimming test (FST) and tail suspension test (TST). Diazepam and fluoxetine were used as standard drugs for anxiolytic and antidepressant tests, respectively. The results showed that 1,8-cineole at 4 × 10-4 mg, and 1,4-cineole at 4 × 10-4 and 4 × 10-3 mg significantly increased the amount of time spent in the light box and the number of entries in the light box in the LDB as well as reduced the number of marbles buried in the MBT relative to those in the control, suggesting an anxiolytic effect. Similarly, 1,8-cineole at 4 × 10-4 and 4 × 10-2 mg and 1,4-cineole at doses of 4 × 10-4 to 4 × 10-2 mg significantly reduced immobility times in the FST and TST relative to those of the control, suggesting an antidepressant activity. The role of the GABAA/benzodiazepine receptor system in the anxiolytic effects of 1,8- and 1,4-cineole was investigated through co-administration of flumazenil, a GABAergic system antagonist. Flumazenil reversed the effects of diazepam and 1,8-cineole, suggesting that 1,8-cineole affects the GABAA/benzodiazepine receptors. Collectively, the results suggest that inhaled 1,8- and 1,4-cineole prevented anxiety and depressive-like symptoms in classic mice models.

Enhanced expression of heme oxygenase-1 in the locus coeruleus can be associated with anxiolytic-like effects.

Some researchers have shown that carbon monoxide (CO) plays a role in emotional behavior modulation through intracellular 3'-5'-guanosine monophosphate mechanisms in the locus coeruleus (LC). In fact, the LC region has a high expression of the heme-oxygenase (HO) enzymes, which are responsible for the production of CO. However, the physiological mechanism by which the HO-CO pathway participates in the modulation of emotional responses in the LC still needs clarification. This study evaluates whether a systemic intraperitoneal treatment is able to alter behavioral responses (in the elevated plus-maze and the light-dark box test) and the expression of the HO-1 and HO-2 enzymes in the LC. The tested treatments are acute (3h before) or chronic (twice daily for 10days) and with a carbon monoxide releaser (tricarbonyldichlororuthenium [II] dimer, or CORM-2) or with a HO-1 inducer compound (cobalt protoporphyrin IX, CoPP). The results for the elevated plus-maze show that CO-for both acute or chronic administration of either drug-ncreased the number of entries into the open arms and the percentage of time spent in the open arms. Regarding the light-dark box test, chronic treatment with either drug increased the time spent in the light compartment. Additionally, treatment with CORM-2 or CoPP, either acutely or chronically, increased HO-1 enzyme expression in the LC cells. This study shows that systemic CO treatment can promote an anxiolytic-like effect and the expression of HO-1 enzymes in LC cells.

Development of a computer-aided-controlling and image analysis system for light/dark box test in mice and rats / 中国比较医学杂志

Objective To develop a computer-aided-controlling and analysis system for light/dark box in mice and rats with a high degree of automation and intelligence.Methods Video recording and image processing were applied to develop the computer-aided-controlling and image analysis system for light/dark box test in mice and rats. The artificial environment was developed. The stability and reliability of the system was validated by male rats. Results The percentage of time spent in the lit chamber in total time was above 79.40%. The data showed that the artificial environment was successful. When the threshold was set at 18 cm/s, the data showed a high correlation coefficient of movement time between the computer and manual recordings(r > 0.99). Classical indexes including transition and time spent in both the lit and dark chambers also showed a high correlation. The model group showed a significantly decrease in the transitions and time spent in the lit chamber compared with the control group, indicating a high stability and reliability of the light/dark box test. Conclusions A stable and highly intelligent computer-aided-controlling and image analysis system for light/dark box test of mice and rats has been developed,and it could be used for pathological mechanism studies of anxiolytics.

Food Seeking in a Risky Environment: A Method for Evaluating Risk and Reward Value in Food Seeking and Consumption in Mice.

Most studies that measure food intake in mice do so in the home cage environment. This necessarily means that mice do not engage in food seeking before consumption, a behavior that is ubiquitous in free-living animals. We modified and validated several commonly used anxiety tests to include a palatable food reward within the anxiogenic zone. This allowed us to assess risk-taking behavior in food seeking in mice in response to different metabolic stimuli. We modified the open field test and the light/dark box by placing palatable peanut butter chips within a designated food zone inside the anxiogenic zone of each apparatus. We then assessed parameters of the interaction with the food reward. Fasted mice or mice treated with ghrelin showed increased consumption and increased time spent in the food zone immediately around the food reward compared to ad libitum fed mice or mice treated with saline. However, fasted mice treated with IP glucose before exposure to the behavioral arena showed reduced time in the food zone compared to fasted controls, indicating that acute metabolic signals can modify the assessment of safety in food seeking in a risky environment. The tests described in this study will be useful in assessing risk processing and incentive salience of food reward, which are intrinsic components of food acquisition outside of the laboratory environment, in a range of genetic and pharmacological models.

Effect of Variable Doses of Zinc Oxide Nanoparticles on Male Albino Mice Behavior.

Zinc oxide nanoparticles (ZnO NPs) have diverse utility these days ranging from being part of nanosensors to be ingredient of cosmetics. Present study was designed to report the effect of variable doses of ZnO NPs on selected aspects of male albino mice behavior. Nano particles were synthesized by sol-gel auto-combustion method (Data not shown here). 10 week old male albino mice were divided into four experimental groups; group A, B and C were orally supplemented with 50 (low dose), 300 (medium dose) and 600 mg/ml solvent/kg body weight (high dose) of ZnO NPs for 4 days. Group D (control) orally received 0.2 M sodium phosphate buffer (solvent for ZnO NPs) for the same duration. A series of neurological tests (Rota rod, open field, novel object and light-dark box test) were conducted in all groups and performance was compared between ZnO NPs treated and control group. Muscular functioning during rota rod test was significantly improved in all ZnO NPs treated mice as compared to control group. While no significant differences in open field, novel object and light-dark box test performance were observed when data from studied parameters of specific ZnO NPs treatment were compared with the control group indicating that applied doses of ZnO NPs did not affect the exploratory, anxiolytic behavior and object recognition capability of adult male albino mice.

Hemokinin-1 mediates anxiolytic and anti-depressant-like actions in mice.

The tachykinin NK1 receptor was suggested to be involved in psychiatric disorders, but its antagonists have failed to be effective as antidepressants in clinical trials. Hemokinin-1 (HK-1), the newest tachykinin, is present in several brain regions and activates the NK1 receptor similarly to substance P (SP), but acts also through other mechanisms. Therefore, we investigated the roles of the Tac4 gene-derived HK-1 in comparison with SP and neurokinin A (NKA) encoded by the Tac1 gene, as well as the NK1 receptor in anxiety and depression-like behaviors in mice. Mice lacking SP/NKA, HK-1 or the NK1 receptor (Tac1-/-, Tac4-/-, Tacr1-/-, respectively) compared to C57Bl/6 wildtypes (WT), and treatment with the NK1 antagonist CP99994 were used in the experiments. Anxiety was evaluated in the light-dark box (LDB) and the elevated plus maze (EPM), locomotor activity in the open field (OFT) tests. Hedonic behavior was assessed in the sucrose preference test (SPT), depression-like behavior in the tail suspension (TST) and forced swim (FST) tests. FST-induced neuronal responsiveness was evaluated with Fos immunohistochemistry in several stress-related brain regions. In the LDB, Tac4-/- mice spent significantly less, while Tacr1-/- and CP99994-treated mice spent significantly more time in the lit compartment. In the EPM only Tac4-/- showed reduced time in the open arms, but no difference was observed in any other groups. In the OFT Tac4-/- mice showed significantly reduced, while Tac1-/- and Tacr1-/- animals increased motility than the WTs, but CP99994 had no effect. NK1-/- consumed markedly more, while Tac4-/- less sucrose solution compared to WTs. In the TST and FST, Tac4-/- mice showed significantly increased immobility. However, depression-like behavior was decreased both in cases of genetic deletion and pharmacological blockade of the NK1 receptor. FST-induced neuronal activation in different nuclei involved in behavioral and neuroendocrine stress responses was significantly reduced in the brain of Tac4 -/- mice. Our results provide the first evidence for an anxiolytic and anti-depressant-like actions of HK-1 through a presently unknown target-mediated mechanism. Identification of its receptor and/or signaling pathways might open new perspectives for anxiolytic and anti-depressant therapies.

Evaluation of anxiolytic-like activity of Vitis vinifera juice in mice.

OBJECTIVE: Scientific studies have shown that Vitis vinifera (V. vinifera) contains flavonoids and stillbenoids. Flavonoids are well known to possess anxiolytic activities. In view of the idea that flavonoids present in V. vinifera could be useful in anxiety, we evaluated anxiolytic-like activity of V. vinifera juice (VVJ). MATERIALS AND METHODS: Light/dark box and the open field test were used to assess the anxiolytic potential of V. vinifera juice (VVJ). The juice was given orally by gavage at the dose of 4 and 8 mL/kg body weight. Diazepam (1 mg/kg i.p.) was used as the standard drug. RESULTS: It was observed that the juice produced significant and dose dependent increase in the time spent in light cubicle (p<0.001), transfer latency from the light to dark cubicle (p<0.001) and the number of transitions between the two cubicles (p<0.001) as compared with the control group. V. vinifera also demonstrated significant and dose dependent increase in ambulation (P<0.001) and rearing (p<0.001) in open field test as compared to the control group. CONCLUSION: In conclusion, the present study establishes the anxiolytic-like activity of VVJ in animal models of anxiety.

Examination of the interaction of different lighting conditions and chronic mild stress in animal model.

We examined the effects of different shift work schedules and chronic mild stress (CMS) on mood using animal model. The most common international shift work schedules in nursing were applied by three groups of Wistar-rats and a control group with normal light-dark cycle. One subgroup from each group was subjected to CMS. Levels of anxiety and emotional life were evaluated in light-dark box. Differences between the groups according to independent and dependent variables were examined with one- and two-way analysis of variance, with a significance level defined at p < 0.05. Interaction of lighting regimen and CMS was proved to be significant according to time spent in the light compartment and the average number of changes between the light and dark compartments. Results of our examination confirm that the changes of lighting conditions evocate anxiety more prominently than CMS. No significant differences were found between the results of the low rotating group and the control group, supposing that this schedule is the least harmful to health. Our results on the association between the use of lighting regimens and the level of CMS provide evidence that the fast rotating shift work schedule puts the heaviest load on the organism of animals.

Animal models for screening anxiolytic-like drugs: a perspective.

Contemporary biological psychiatry uses experimental animal models to increase our understanding of affective disorder pathogenesis. Modern anxiolytic drug discovery mainly targets specific pathways and molecular determinants within a single phenotypic domain. However, greater understanding of the mechanisms of action is possible through animal models. Primarily developed with rats, animal models in anxiety have been adapted with mixed success for mice, easy-to-use mammals with better genetic possibilities than rats. In this review, we focus on the three most common animal models of anxiety in mice used in the screening of anxiolytics. Both conditioned and unconditioned models are described, in order to represent all types of animal models of anxiety. Behavioral studies require careful attention to variable parameters linked to environment, handling, or paradigms; this is also discussed. Finally, we focus on the consequences of re-exposure to the apparatus. Test-retest procedures can provide new answers, but should be intensively studied in order to revalidate the entire paradigm as an animal model of anxiety.

La psiquiatría biológica actual emplea modelos animales experimentales para aumentar la comprensión acerca de la patogénesis del trastorno afectivo. El descubrimiento de los fármacos ansiolíticos modernos apunta principalmente a vías especificas y determinantes moleculares dentro de un dominio fenotípico único. Sin embargo, es posible una mayor comprensión de los mecanismos de acción a través de los modelos animales. Los modelos animales de ansiedad, inicialmente desarrollados en ratas, han sido adaptados con relativo éxito en ratones, un mamífero fácil de emplear y con mejores posibilidades genéticas que las ratas. Esta revisión se focaliza en los tres modelos animales de ansiedad empleados más comúnmente en ratones, que se utilizan para la evaluación de ansiolíticos. Se describen tanto los modelos condicíonados como los incondicionados con el fin de representar todos los tipos de modelos animales de ansiedad. También se analiza el gran cuidado que se debe poner en los parámetros variables relacionados con el ambiente, la manipulación o el paradigma que tienen los estudios de comportamiento. Por último se centra la atención en las consecuentias de la re-exposición al aparato. Los procedimientos de test-retest pueden proportionar nuevas respuestas, pero deben ser ampliamente estudiados para revalidar todo el paradigma como un modelo animal de ansiedad.

La psychiatrie biologique actuelle utilise les modèles animaux expérimentaux pour mieux comprendre la pathogenèse des troubles affectifs. La recherche moderne sur les anxiolytiques cible principalement les voies spécifiques et les déterminants moléculaires dans un phénotype unique. Les modèles animaux permettent néanmoins de mieux comprendre les mécanismes d'action. D'abord développés chez le rat, les modèles animaux de l'anxiété ont été adaptés avec un succès variable chez la souris, un mammifère facile à utiliser dont les possibilités génétiques sont meilleures que celles du rat. Dans cet article, nous nous intéressons aux trois modèles d'anxiété les plus courants chez la souris, utilisés pour la sélection d'anxiolytiques. Nous décrivons à la fois les modèles conditionnés et non conditionnés afin de représenter tous les types de modèles animaux d'anxiété. Les études de comportement nécessitant une observation soigneuse des paramètres variables liés à l'environnement, aux façons de réagir ou aux modèles, sont aussi analysées. Enfin nous nous intéressons aux conséquences de la ré-exposition au dispositif. Les techniques de fiabilité test-retest peuvent fournir de nouvelles réponses mais doivent être étudiées en profondeur afin de revalider le modèle entier comme modèle animal de l'anxiété.

Anxiolytic-like effects of carvacryl acetate, a derivative of carvacrol, in mice.

Studies showing anxiolytic-like properties of natural products have grown. This paper evaluated if carvacryl acetate (CA) could be studied as an alternative drug to treat anxiety disorders. Elevated plus maze (EPM) tests , light-dark box (LDB) tests, and marble-burying tests (MBTs) were performed on mice. In the first protocol, the anxiolytic-like activities of CA 25, 50, 75 and 100mg/kg at single doses were compared to those of the vehicle, buspirone 5mg/kg (BUSP) and diazepam 1mg/kg (DZP). In the second protocol, the anxiolytic-like actions of CA were tested for GABAergic and serotonergic systems. The time spent in the open arms (TSOA) and the number of open arms entries (NOAE) were measured in EPM; the time spent in the light box (TSLB) and the number of entries to light box (NELB) were measured in LDB; and the number of marbles buried (NMB) were measured in MBT. CA increased TSOA and NOAE in the EPM, as well as TSLB and NELB in the LDB and the NMB in the MBT. The anxiolytic-like activity of CA 25; 50; 75 and 100mg/kg was not associated with psychomotor retardation in the open field test and in the Rota rod test, contrarily with what happened with DZP. In the second protocol, to suggest the mechanism of action of CA, flumazenil 25mg/kg ip (FLU) and WAY 100,635 10mg/kg ip (WAY-5-HT1A antagonist) were also used. FLU+CA100 reduced TSOA in the EPM when compared to CA100 but WAY+CA100 did not. In LDB, FLU+CA100 reduced the TSLB when compared to CA100 but WAY+CA100 did not. In the MBT, FLU+CA100 inhibited the effect of CA100 on the NMB but WAY+CA100 did not. In conclusion, CA seems to have an anxiolytic-like effect, probably due to GABAergic agonist action, without psychomotor side effects.