Sex differences in the anticompulsive-like effect of memantine: Involvement of nitric oxide pathway but not AMPA receptors.

Memantine, an N-Methyl-D-Aspartate (NMDA) antagonist, has been examined as a potential treatment for Obsessive-Compulsive Disorder (OCD). Yet, there is limited knowledge regarding how it works to reduce compulsive behaviour and whether it has different effects on individuals based on their sex. Herein, we investigated if there are sex differences in the anticompulsive-like effect of memantine in adult Swiss mice. Additionally, we explored whether the nitric oxide (NO) pathway and α-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) receptors play a role in memantine's effects. To start, we assessed the impact of a single intraperitoneal dose of memantine (at 3, 5, and 10 mg/kg) on behaviours exhibited in the open field test (OFT) and the marble-burying test (MBT), the latter being a predictive test for anticompulsive effects. All doses of memantine reduced marble-burying behaviour in both male and female mice without affecting their locomotor activity in the OFT. This anticompulsive-like effect was also confirmed in another predictive test, the nest-building test, with the highest memantine dose (10 mg/kg) reducing nest-building behaviour without significant differences between male and female mice. We observed that pre-treatment with L-arginine, a NO precursor, mitigated the anticompulsive-like effect of memantine in male mice but had no effect in female mice in the MBT. Finally, NBQX, an AMPA receptor antagonist, did not block the anticompulsive-like effect of memantine. In summary, our study suggests that the anticompulsive-like effect of memantine does not appear to be sex-specific, does not depend on AMPA receptors, and involves the NO pathway primarily in male mice.

Effect of Agaricus blazei Murill on exploratory behavior of mice-model / Efeito de Agaricus blazei Murill no comportamento exploratório de modelo de camundongo

Abstract Increased anxiety and depressive symptoms have reported to be its association with long term illness. Because of having unwanted effects of newly available drugs, patients administering anxiolytic drugs usually discontinue the treatment before they are completely recovered. Therefore, there is a serious need to develop new anxiolytic drugs. The anxiolytic effect of hydro-alcoholic extract of Agaricus blazei in animal models was assessed. 24 male mice (Mus musculus genus) were included in the study. Four groups were prepared and each group contained six animals. The groups were vehicle control, positive control (diazepam 1.0 mg/kg, i.p.) as well as two treatment groups receiving Agaricus blazei hydro-alcoholic extract at a dose of 136.50 mg/kg and 273.0 mg/kg orally. The Marble burying test, Nestlet shredding test and Light and Dark box test used to assess anxiolytic activity. Mice administered with diazepam 1.0 mg/kg, i.p. while hydro-alcoholic extract of AbM (136.50 and 273.0 mg/kg, respectively) was administered via oral route which exhibited marked reduction in number of marbles-burying as compared to vehicle control group. Mice administered with diazepam 1.0 mg/kg, i.p. and Oral administration of hydro-alcoholic extract of AbM (136.50 and 273.0 mg/kg, respectively) exhibited significant decrease in nestlet shredding in comparison to vehicle control group. The oral administration of hydro-alcoholic extract at a dose of 136.5mg/kg and 273mg/kg showed elevation in time spent in light box and was comparable to standard treated group while time spent by mice following oral administration of hydro-alcoholic extract of Agaricus blazei at a dose of 273.0 mg/kg also showed elevation and was found to be more near to standard treated group (diazepam 1 mg/kg, i.p.).

Resumo O aumento da ansiedade e dos sintomas depressivos têm relatado sua associação com doenças de longa duração. Por causa dos efeitos indesejáveis dos novos medicamentos disponíveis, os pacientes que administram medicamentos ansiolíticos geralmente interrompem o tratamento antes de estarem completamente recuperados. Portanto, há uma necessidade séria de desenvolver novos medicamentos ansiolíticos. Foi avaliado o efeito ansiolítico do extrato hidroalcoólico de Agaricus blazei em modelos animais. Vinte e quatro camundongos machos (gênero Mus musculus) foram incluídos no estudo. Quatro grupos foram preparados, e cada grupo continha seis animais. Os grupos foram controle de veículo, controle positivo (diazepam 1,0 mg/kg, i.p.), bem como dois grupos de tratamento recebendo extrato hidroalcoólico de Agaricus blazei na dose de 136,50 mg/kg e 273,0 mg/kg por via oral. O teste de enterrar Marble, o teste de retalhamento Nestlet e o teste de caixa clara e escura são usados ​​para avaliar a atividade ansiolítica. Camundongos foram administrados com diazepam 1,0 mg/kg, i.p., enquanto o extrato hidroalcoólico de AbM (136,50 e 273,0 mg/kg, respectivamente) foi administrado por via oral, que exibiu redução acentuada no número de mármores enterrados em comparação com o grupo de controle de veículo. Camundongos administrados com diazepam 1,0 mg/kg, i.p. e a administração oral de extrato hidroalcoólico de AbM (136,50 e 273,0 mg/kg, respectivamente) exibiu diminuição significativa na trituração de ninhos em comparação ao grupo de controle de veículo. A administração oral de extrato hidroalcoólico na dose de 136,5mg/kg e 273mg/kg mostrou elevação no tempo gasto na caixa de luz e foi comparável ao grupo tratado padrão, enquanto o tempo gasto por camundongos após a administração oral de extrato hidroalcoólico de Agaricus blazei na dose de 273,0 mg/kg também mostrou elevação e foi mais próximo do grupo tratado padrão (diazepam 1 mg/kg, ip).

Effect of Agaricus blazei Murill on exploratory behavior of mice-model

Abstract Increased anxiety and depressive symptoms have reported to be its association with long term illness. Because of having unwanted effects of newly available drugs, patients administering anxiolytic drugs usually discontinue the treatment before they are completely recovered. Therefore, there is a serious need to develop new anxiolytic drugs. The anxiolytic effect of hydro-alcoholic extract of Agaricus blazei in animal models was assessed. 24 male mice (Mus musculus genus) were included in the study. Four groups were prepared and each group contained six animals. The groups were vehicle control, positive control (diazepam 1.0 mg/kg, i.p.) as well as two treatment groups receiving Agaricus blazei hydro-alcoholic extract at a dose of 136.50 mg/kg and 273.0 mg/kg orally. The Marble burying test, Nestlet shredding test and Light and Dark box test used to assess anxiolytic activity. Mice administered with diazepam 1.0 mg/kg, i.p. while hydro-alcoholic extract of AbM (136.50 and 273.0 mg/kg, respectively) was administered via oral route which exhibited marked reduction in number of marbles-burying as compared to vehicle control group. Mice administered with diazepam 1.0 mg/kg, i.p. and Oral administration of hydro-alcoholic extract of AbM (136.50 and 273.0 mg/kg, respectively) exhibited significant decrease in nestlet shredding in comparison to vehicle control group. The oral administration of hydro-alcoholic extract at a dose of 136.5mg/kg and 273mg/kg showed elevation in time spent in light box and was comparable to standard treated group while time spent by mice following oral administration of hydro-alcoholic extract of Agaricus blazei at a dose of 273.0 mg/kg also showed elevation and was found to be more near to standard treated group (diazepam 1 mg/kg, i.p.).

Resumo O aumento da ansiedade e dos sintomas depressivos têm relatado sua associação com doenças de longa duração. Por causa dos efeitos indesejáveis dos novos medicamentos disponíveis, os pacientes que administram medicamentos ansiolíticos geralmente interrompem o tratamento antes de estarem completamente recuperados. Portanto, há uma necessidade séria de desenvolver novos medicamentos ansiolíticos. Foi avaliado o efeito ansiolítico do extrato hidroalcoólico de Agaricus blazei em modelos animais. Vinte e quatro camundongos machos (gênero Mus musculus) foram incluídos no estudo. Quatro grupos foram preparados, e cada grupo continha seis animais. Os grupos foram controle de veículo, controle positivo (diazepam 1,0 mg/kg, i.p.), bem como dois grupos de tratamento recebendo extrato hidroalcoólico de Agaricus blazei na dose de 136,50 mg/kg e 273,0 mg/kg por via oral. O teste de enterrar Marble, o teste de retalhamento Nestlet e o teste de caixa clara e escura são usados para avaliar a atividade ansiolítica. Camundongos foram administrados com diazepam 1,0 mg/kg, i.p., enquanto o extrato hidroalcoólico de AbM (136,50 e 273,0 mg/kg, respectivamente) foi administrado por via oral, que exibiu redução acentuada no número de mármores enterrados em comparação com o grupo de controle de veículo. Camundongos administrados com diazepam 1,0 mg/kg, i.p. e a administração oral de extrato hidroalcoólico de AbM (136,50 e 273,0 mg/kg, respectivamente) exibiu diminuição significativa na trituração de ninhos em comparação ao grupo de controle de veículo. A administração oral de extrato hidroalcoólico na dose de 136,5mg/kg e 273mg/kg mostrou elevação no tempo gasto na caixa de luz e foi comparável ao grupo tratado padrão, enquanto o tempo gasto por camundongos após a administração oral de extrato hidroalcoólico de Agaricus blazei na dose de 273,0 mg/kg também mostrou elevação e foi mais próximo do grupo tratado padrão (diazepam 1 mg/kg, ip).

S-ketamine exerts sex- and dose-dependent anti-compulsive-like effect as monotherapy or in augmentation to fluoxetine.

Since a significant body of studies supports the involvement of glutamatergic neurotransmission in the neurobiology of obsessive-compulsive disorder (OCD). Ketamine, a glutamate N-methyl-D-aspartate (NMDA) receptor antagonist with rapid and sustained antidepressant effect, raises as a potential new anti-OCD drug. Evidence from pre-clinical studies indicates that female mice are more sensitive than male mice to ketamine antidepressant effects. Our group previously showed that S-ketamine, one ketamine enantiomer, induces an acute anti-compulsive effect in male mice. Herein, we investigated this S-ketamine effect in female adult Swiss mice as monotherapy or as an adjuvant to fluoxetine, a selective serotonin reuptake inhibitor (SSRI), compared to male mice. For this purpose, we assessed the S-ketamine anti-compulsive-like effect in the marble-burying (MBT) and nest-building (NBT) tests in adult female Swiss mice. S-ketamine reduced the compulsive-like behaviour of female mice in both animal tests in a dose larger (30 mg/kg) than the effective dose in male Swiss mice (10 mg/kg, Tosta et al., 2019). The association of sub-effective doses of S-ketamine and fluoxetine effectively reduced the marble-burying behaviour of both male and female Swiss mice, although male mice present a better response. The variation of female sex hormones (oestrogen and progesterone), inferred by oestrous cycle and ovariectomy, did not influence S-ketamine's response. In conclusion, we found that female mice are less sensitive to S-ketamine's anti-compulsive-like effect than male mice as monotherapy or adjuvant treatment, but oscillations in female sex hormones concentrations do not seem to explain this difference.

Short or moderate-time exposure to the inhalational anesthetics isoflurane and sevoflurane does not alter the marble-burying behavior in mice.

Several studies suggest the involvement of glutamatergic neurotransmission in obsessive-compulsive disorder (OCD). Some NMDA glutamatergic receptor antagonists, such as the general anesthetic ketamine, have shown anti-OCD effects in preclinical and clinical studies. Therefore, we investigated whether the inhalational anesthetics isoflurane and sevoflurane, which are general anesthetics acting as NMDA receptor antagonists, would induce the same effects. To test our hypothesis, adult male Swiss mice were exposed to different concentrations of isoflurane (0.5, 1.5 or 3 %) or sevoflurane (0.8, 2.5 or 4 %) for 20 min (short-time exposure) or 1 h (moderate-time exposure) and submitted to the open field test (OFT) and the marble-burying test (MBT) in the same day (acute effect) or 7 days (long-lasting effect) after anesthetics administration. We found that single short or moderate-time exposure to isoflurane or sevoflurane, at sub-anesthetic or anesthetic concentrations, did not affect marble-burying behavior acutely or even 7 days after their administration. The same treatment schedules with isoflurane or sevoflurane did not impair total distance travelled in the OFT. A single moderate-time exposure to isoflurane (3 %) reduced, acutely, the central exploration of the open field, suggesting an anxiogenic-like effect of isoflurane in mice. Our results suggest that isoflurane and sevoflurane may not be promising anti-compulsive drugs.

Impaired emotional response to stress in mice lacking galectin-1 or galectin-3.

Galectin-1 (Gal-1) and galectin-3 (Gal-3) are multifunctional glycan-binding proteins, expressed in the brain and in its limbic structures that are involved in behavioral control. Gal-1 induces the expression of the brain-derived neurotrophic factor (BDNF) and promotes adult neural stem cells proliferation, biological events impaired in stress-related psychiatric disorders, such as depression and anxiety. Despite that, there is no evidence regarding galectin involvement in emotional control during stressful situations. Thus, we analyzed the behavioral phenotype of Gal-1 or Gal-3 knock-out mice (Gal-1 KO or Gal-3 KO) in different experimental models predictive of depressive and compulsive-like behaviors. METHODS: C57BL-6 Gal-1 KO, Gal-3 KO, and wild-type mice (WT) were analyzed under the open field test (OFT) and, 6 h later, under the forced swim test (FST). Additionally, independent groups of male mice, lacking galectins or not, were exposed to the tail suspension test (TST) or to the marble burying test (MBT). The hippocampus and prefrontal cortex (PFC) of the mice submitted to MBT were dissected to access BDNF levels. RESULTS: Both Gal-1 and Gal-3 KO mice showed increased time of immobility in the FST and in the TST compared to WT animals, thus reflecting an impaired stress-coping behavior. Additionally, Gal-1 and Gal-3 KO female mice presented increased compulsive-like behavior in the MBT, without significant changes in the locomotor activity. BDNF levels were found to be decreased in the PFC of Gal-1 KO mice. DISCUSSION: Our results demonstrate that the absence of either endogenous Gal-1 and Gal-3 impairs stress-coping and increases compulsive-like behavior, suggesting that Gal-1 and Gal-3 are involved in the neurobiology of depression and obsessive-compulsive-like disorder.

Cafeteria diet in breastfeeding dams promotes anxiolytic effects, accumulation of adipose tissue, and impacts offspring development / La dieta de la cafetería en las madres que amamantan promueve los efectos ansiolíticos y la acumulación de tejido adiposo, y afecta el desarrollo de la descendencia

The aim of this study was to evaluate the nutritional and behavioral effects of a cafeteria diet in dams during the breastfeeding period and in their offspring from weaning until early adulthood (70 days old). Pregnant Wistar rats were fed a chow diet until delivery. Postnatally (D0), litters were culled to 8 pups and lactating dams received control (CTRL n= 6) or cafeteria (CAF n= 6) diets and water ad libitum. At the end of the breastfeeding period, male offspring were placed in individual boxes receiving the same treatment from their respective dams (CTRL or CAF) until adulthood (70 days). All nutritional and behavioral evaluations were performed with the dams (n= 12) during the breastfeeding phase and with the male offspring (n= 24) after weaning to adulthood. CAF dams demonstrated a lower caloric and protein intake; higher intake of fats; loss of weight; greater accumulation of adipose tissue; and an anxiolytic effect. CAF male offspring showed lower caloric intake; higher intake of fats; and accumulation of adipose tissue. In addition, these animals continued to have decreased body weight, body length and tibia-femur length in relation to CTRL. In dams, a cafeteria diet promoted alterations in body composition and anxiety, and in offspring the diet resulted in adequate development.

El objetivo de este estudio fue evaluar los efectos nutricionales y de comportamiento de la dieta de la cafetería en las madres durante el período de lactancia materna y en su descendencia desde el destete hasta la edad adulta temprana (70 días de edad). Ratas Wistar embarazadas fueron alimentadas con una dieta estándar hasta el parto. Postnatalmente (D0), las camadas se ajustaron en 8 crías y las madres lactantes recibieron las dietas control (CTRL n= 6) o cafetería (CAF n= 6) además de agua ad libitum. Al final del período de lactancia materna, las proles machos fueron colocados en cajas individuales recibiendo el mismo tratamiento de sus respectivas madres (CTRL o CAF) hasta la edad adulta (70 días). Todas las evaluaciones nutricionales y comportamentales se realizaron con las madres (n= 12) durante la fase de lactancia y con la prole masculina (n= 24) después del destete hasta la edad adulta. Las madres CAF demostraron una menor ingesta calórica y proteica; mayor ingestión de grasas; pérdida de peso; mayor acumulación de tejido adiposo; y un efecto ansiolítico. La prole masculina CAF presentó menor consumo calórico; mayor ingestión de grasas; y la acumulación de tejido adiposo. Además, estos animales presentaron menor peso corporal, longitud corporal, y longitud de la tibia-fémur, en relación a CTRL. En las madres, la dieta de cafetería promovió cambios en la composición corporal y ansiedad, y en la prole la dieta comprometió el desarrollo adecuado.

Dual mechanism of TRKB activation by anandamide through CB1 and TRPV1 receptors.

BACKGROUND: Administration of anandamide (AEA) or 2-arachidonoylglycerol (2AG) induces CB1 coupling and activation of TRKB receptors, regulating the neuronal migration and maturation in the developing cortex. However, at higher concentrations AEA also engages vanilloid receptor TRPV1, usually with opposed consequences on behavior. METHODS AND RESULTS: Using primary cell cultures from the cortex of rat embryos (E18) we determined the effects of AEA on phosphorylated TRKB (pTRK). We observed that AEA (at 100 and 200 nM) induced a significant increase in pTRK levels. Such effect of AEA at 100 nM was blocked by pretreatment with the CB1 antagonist AM251 (200 nM) and, at the higher concentration of 200 nM by the TRPV1 antagonist capsazepine (200 nM), but mildly attenuated by AM251. Interestingly, the effect of AEA or capsaicin (a TRPV1 agonist, also at 200 nM) on pTRK was blocked by TRKB.Fc (a soluble form of TRKB able to bind BDNF) or capsazepine, suggesting a mechanism dependent on BDNF release. Using the marble-burying test (MBT) in mice, we observed that the local administration of ACEA (a CB1 agonist) into the prelimbic region of prefrontal cortex (PL-PFC) was sufficient to reduce the burying behavior, while capsaicin or BDNF exerted the opposite effect, increasing the number of buried marbles. In addition, both ACEA and capsaicin effects were blocked by previous administration of k252a (an antagonist of TRK receptors) into PL-PFC. The effect of systemically injected CB1 agonist WIN55,212-2 was blocked by previous administration of k252a. We also observed a partial colocalization of CB1/TRPV1/TRKB in the PL-PFC, and the localization of TRPV1 in CaMK2+ cells. CONCLUSION: Taken together, our data indicate that anandamide engages a coordinated activation of TRKB, via CB1 and TRPV1. Thus, acting upon CB1 and TRPV1, AEA could regulate the TRKB-dependent plasticity in both pre- and postsynaptic compartments.

S-ketamine reduces marble burying behaviour: Involvement of ventromedial orbitofrontal cortex and AMPA receptors.

Previous clinical and pre-clinical studies suggest the involvement of ventromedial orbitofrontal cortex (vmOFC) and glutamatergic neurotransmission in obsessive-compulsive disorder (OCD). Ketamine, an NMDA glutamatergic receptor antagonist, has shown a rapid and long-lasting antidepressant effect, but its anti-compulsive effect has been scarcely investigated. The antidepressant effect of ketamine involves NMDA receptor blockade, AMPA receptor activation, increased serotonin (5-HT) release and attenuation of nitric oxide (NO) synthesis. It is not known if these mechanisms are involved in ketamine-induced anti-compulsive effect. Therefore, we firstly investigated the effect of S-ketamine in the marble-burying test (MBT), a model for screening of drugs with potential to treat OCD. Then, we evaluated whether ketamine effects in the MBT would involve the vmOFC, be dependent on AMPA receptors, facilitation of serotonergic neurotransmission and inhibition of nitrergic pathway. Our results showed that single systemic (10 mg/kg) and intra-vmOFC (10 nmol/side) administration of S-ketamine reduces marble burying behaviour (MBB) without affecting spontaneous locomotors activity. Pre-treatment with NBQX (3 mg/kg; AMPA receptor antagonist) blocked the reduction of MBB induced by S-ketamine. However, pre-treatment with p-CPA (150 mg/kg/day; a 5-HT synthesis inhibitor), WAY100635 (3 mg/kg; a 5-HT1A receptor antagonist), or L-arginine (500 mg/kg; a nitric oxide precursor) did not counteract S-ketamine effect in the MBT. In contrast, associating sub-effective doses of L-NAME (10 mg/kg; NOS inhibitor) and S-ketamine (3 mg/kg) decreased MBB. In conclusion, the reduction of MBB by S-ketamine strengthens its possible anti-compulsive effect. The vmOFC is involved in this S-ketamine effect, which is dependent on the activation of AMPA receptors.

A high-refined carbohydrate diet facilitates compulsive-like behavior in mice through the nitric oxide pathway.

Obesity is characterized by abnormal adipose tissue expansion and is associated with chronic inflammation. Obesity itself may induce several comorbidities, including psychiatric disorders. It has been previously demonstrated that proinflammatory cytokines are able to up-regulate inducible nitric oxide synthase (iNOS) and nitric oxide (NO) release, which both have a role in compulsive related behaviors. OBJECTIVE: To evaluate whether acute or chronic consumption of a high-refined carbohydrate-containing (HC) diet will modify burying-behavior in the Marble Burying Test (MBT) through augmentation of NO signaling in the striatum, a brain region related to the reward system. Further, we also verified the effects of chronic consumption of a HC diet on the reinforcing effects induced by cocaine in the Conditioned Place Preference (CPP) test. METHODS: Male BALB/c mice received a standard diet (control diet) or a HC diet for 3 days or 12 weeks. RESULTS: An increase in burying behavior occurred in the MBT after chronic consumption of a HC diet that was associated with an increase of nitrite levels in the striatum. The pre-treatment with Aminoguanidine (50 mg/kg), a preferential inhibitor of iNOS, prevented such alterations. Additionally, a chronic HC diet also induced a higher expression of iNOS in this region and higher glutamate release from striatal synaptosomes. Neither statistical differences were observed in the expression levels of the neuronal isoform of NOS nor in microglia number and activation. Finally, the reinforcing effects induced by cocaine (15 mg/kg, i.p.) during the expression of the conditioned response in the CPP test were not different between the chronically HC diet fed mice and the control group. However, HC diet-feeding mice presented impairment of cocaine-preference extinction. CONCLUSION: Altogether, our results suggest that the chronic consumption of a HC diet induces compulsive-like behavior through a mechanism possibly associated with NO activation in the striatum.

Exercise attenuates alveolar bone loss and anxiety-like behaviour in rats with periodontitis.

AIM: To evaluate the effects of physical training on inflammatory and behavioural parameters of Wistar rats with periodontal disease (PD). MATERIALS AND METHODS: Twenty four animals were distributed in a 2 × 2 factorial design (with and without exercise, with and without PD). Trained animals swimmed one hour daily during 8 weeks. PD was induced by ligature 14 days before the end of experiment, and in the last week, all animals were submitted to the Marble Burying Test. Histomorphometric analyses of the mandibles and expression of cytokines were conducted by Western blotting. We also evaluated the morphometry of hippocampal astrocytes using anti-glial fibrillary acidic protein antibody. RESULTS: Physical training attenuated bone loss and epithelial attachment loss levels of rats with PD. Trained animals with PD presented lower TNF-α expression in periodontal tissues while IL-10 was increased. TNF-α/IL-10 ratio was lower in trained animals with PD compared to those with induced periodontitis. PD increased anxiety-like behaviour, and physical training attenuated this parameter. Exercise increased the ramifications of hippocampal astrocytes in rats without PD. CONCLUSIONS: Exercise decreased anxiety behaviour, inflammatory proteins expression and bone loss in rats with PD.

Anxiolytic-like effects of phytol: possible involvement of GABAergic transmission.

Phytol, a branched chain unsaturated alcohol, is particularly interesting because it is an isolated compound from essential oils of different medicinal plants. The aim of this study was to evaluate the anxiolytic-like effects of phytol in animal models to clarify their possible action mechanism. After acute intraperitoneal treatment with phytol at doses of 25, 50 and 75 mg/kg behavioral models of open-field, elevated-plus-maze, rota-rod, light-dark, marble-burying and pentobarbital sleeping time tests were utilized. In open field test, phytol (25, 50 and 75 mg/kg) [p<0.01] increased the number of crossings and rearings. However, the number of groomings [p<0.01] was reduced. Likewise, the number of entries and the time spent in light space were increased [p<0.01] while the number of marble-burying was decreased [p<0.001], in elevated-plus-maze, light-dark and marble-burying tests, respectively. In motor activity test, phytol (75 mg/kg) impaired the rota-rod performance of mice [p<0.01]. In pentobarbital sleeping time test, phytol 75 mg/kg decreased for latency of sleeping and phytol (25, 50 and 75 mg/kg) increased the sleep time when compared to negative control [p<0.05]. All these effects were reversed by pre-treatment with flumazenil (2.5mg/kg, i.p.), similarly to those observed with diazepam (2mg/kg, i.p.; positive control) suggesting that the phytol presents mechanism of action by interaction with the GABAergic system. These findings suggest that acute administration of phytol exerts an anxiolytic-like effect on mice. Furthermore, suppose that phytol interacts with GABAA receptor, probably at the receptor subtypes that mediate benzodiazepines effects, to produce sedative and anxiolytic activities.

Cannabidiol reverses the mCPP-induced increase in marble-burying behavior.

Cannabidiol (CBD), one of the main components of Cannabis sp., presents clinical and preclinical anxiolytic properties. Recent results using the marble-burying test (MBT) suggest that CBD can also induce anticompulsive-like effects. Meta-chloro-phenyl-piperazine (mCPP) is a nonspecific serotonergic agonist (acting mainly at 5HT1A, 5HT2C and 5HT1D receptors) reported to increase symptoms in OCD patients and block the anticompulsive-like effect of serotonin reuptake inhibitors (SRIs) in animal models. The aim of this study was to investigate the interference of CBD on mCPP effects in repetitive burying. Administration of mCPP showed dual effects in the MBT, increasing the number of buried marbles at lower (0.1 mg/kg) while decreasing it at higher doses (1 mg/kg), an effect not related to a general increase in anxiety-like behavior. As found previously, CBD (30 mg/kg) and the positive control fluoxetine (FLX; 10 mg/kg) decreased burying behavior without changing general exploratory activity. A similar effect was found when subeffective doses of CBD (15 mg/kg) and FLX (3 mg/kg) were administered together. These subeffective doses alone were also able to block mCPP-induced repetitive burying. The results, in addition to reinforcing a possible anticompulsive effect of CBD, also suggest that mCPP-induced repetitive burying could be a useful test for the screening of compounds with presumed anticompulsive properties.

Antidepressant- and anticompulsive-like effects of purinergic receptor blockade: involvement of nitric oxide.

Activation of purinergic receptors by ATP (P2R) modulates glutamate release and the activation of post-synaptic P2R is speculated to induce nitric oxide (NO) synthesis. Increased glutamatergic and nitrergic signaling have been involved in the neurobiology of stress-related psychiatric disorders such as anxiety and depression. Therefore, the aim of this study was to test the effects of two P2R antagonists (PPADS and iso-PPADS) in animals submitted to models predictive of antidepressant-, anxiolytic- and anticompulsive-like effects. Swiss mice receiving PPADS at 12.5mg/kg showed reduced immobility time in the forced swimming test (FST) similarly to the prototype antidepressant imipramine (30mg/kg). This dose was also able to decrease the number of buried marbles in the marble-burying test (MBT), an anticompulsive-like effect. However, no effect was observed in animals submitted to the elevated plus maze (EPM) and to the open field test. The systemic administration of iso-PPADS, a preferential P2XR antagonist, also reduced the immobility time in FST, which was associated to a decrease in NOx levels in the prefrontal cortex. In addition, P2X7 receptor was found co-immunoprecipitated with neuronal nitric oxide synthase (NOS1) in the prefrontal cortex. These results suggest that P2X7, possibly coupled to NOS1, could modulate behavioral responses associated to stress-related disorders and it could be a new target for the development of more effective treatments for affective disorders.

Anxiolytic-like and sedative effects of Hydrocotyle umbellata L., Araliaceae, extract in mice

The plant Hydrocotyle umbellata L., Araliaceae (water pennywort), is widely used in Brazilian folk medicine to reduce anxiety. This work investigates the anxiolytic-like effects of the ethanol extract from H. umbellata subterraneous parts as well as the extract's other putative central nervous system effects that could justify its common use. Oral dosing of the extract (0.3 and 1 g/kg) clearly showed an anxiolytic-like profile in the elevated plus maze test where it increased the percentage of entries into and the time spent in the open arms of the maze. In the marble-burying test, the extract induced anxiolytic-like effects only at a dose of 1 g/kg, which also causes mild sedative properties in other models. The sedated state was characterized by a slight reduction in spontaneous exploratory activity during the open field test and a potentiating of pentobarbital-induced hypnosis. No signs of motor impairment were detected in the rota rod or chimney tests. The extract did not show antidepressant properties in mice as assessed by the forced swimming test. These results support the use of H. umbellata in Brazilian folk medicine as an anxiolytic and contribute to the scientific knowledge of this possible phytotherapeutic resource.

Anxiolytic effects of Dolichandrone falcata Seem., Bignoniaceae, stem-bark in elevated plus maze and marble burying test on mice / Efeitos ansiolíticos das cascas de Dolichandrone falcata Seem., Bignoniaceae, em teste do labirinto em cruz elevada e teste de esconder esferas, em camundongos

Dolichandrone falcata Seem., Bignoniaceae, is a deciduous tree commonly known as Medshingi in local areas of Toranmal region of Maharashtra, India. Its bark paste is applied on fractured or dislocated bones, used as a fish poison; bark juice is used in cases of menorragia and leucorrhoea. The leaves of the plant have afforded chrysin-7-rutinoside. The present study was carried out to investigate the anxiolytic effects of methanol extract (DFBM), ethyl acetate extract (DFBEA) and isolated compound DFB (V+VI) of D. falcata stem-bark using animal models. Anxiolytic effects were studied by elevated plus maze (EPM) and marble burying test (MBT) assay. The crude dried DFBM and DFBEA extract was prepared in doses of 100, 200 and 400 mg/kg whereas DFB (V+VI) compound was prepared in doses of 50, 100 and 200 mg/kg and were administered orally to mice for evaluation of anxiolytic activity. DFBEA 400 and DFB (V+VI) 200 mg/kg produced highly significant (p <0.01) anxiolytic effects in dose dependent manner by increasing the time spent on and the number of entries into the open arms of the EPM and by decreasing the number of marbles buried by mice in MBT test. This study showed that the DFBM, DFBEA extracts and DFB (V+VI) isolated compound possesses potential pharmacological active constituents flavonoids (like chrysin) which may be responsible for the anxiolytic activity.

Dolichandrone falcata Seem., Bignoniaceae, é uma árvore do tipo decidua, comumente conhecida como "Medshingi" na da região Toranmal de Maharashtra, na Índia. Uma pasta da casca é aplicada em fraturas ou luxação dos ossos e usada como veneno de peixe; o suco da casca é usada em casos de menorragia e leucorréia. Das folhas da planta foi isolado crisina-7-rutinoside. O presente estudo foi realizado para investigar os efeitos ansiolíticos do extrato metanólico (DFBM), acetato de etila (DFBEA) e compostos isolados DFB (V + VI) de D. falcata utilizando a casca do tronco em modelos animais. Os efeitos ansiolíticos foram estudados por labirinto em cruz elevada (EPM) e o ensaio de esconder esferas de mármore (MBT). Os extratos bruto e seco DFBM DFBEA foram preparados em doses de 100, 200 e 400 mg/kg, enquanto que o composto DFB (V + VI) foi preparado em doses de 50, 100 e 200 mg/kg e foram administrados em camundongos para avaliação da atividade ansiolítica. DFBEA 400 and DFB (V+VI) 200 mg/kg produziram efeitos ansiolíticos significantes (p<0.01), de maneira dose-dependente, por aumentar o tempo despendido e o número de entradas nos braços abertos do EPM e por diminuir o número de esferas escondidas pelos camundongos no teste do MBT. Este estudo mostrou que os extratos DFBM, DFBEA e o composto isolado DFB (V + VI), contendo flavonóides com potencial farmacológico (como a crisina) podem ser o responsável pela atividade ansiolítica.