Maternal separation and early social enrichment increase anxietyrelated behaviours of adolescent rats in the elevated plus maze / La separación materna y el enriquecimiento social temprano aumentan los comportamientos relacionados con ansiedad de ratas adolescentes en el laberinto en cruz elevado

Abstract Introduction: Adverse or favourable rearing conditions early in life affect emotional response during adolescence. To study the effect of early rearing on emotional response, animal models such as maternal separation (MS) and social enrichment (SE) by community nesting have been useful. However, the comparison of the effect of MS and SE on anxiety-related behaviours in adolescent rats is unknown. Objective: This study aimed to assess the effects of MS and SE on the emotional response of adolescent rats exposed to the elevated plus-maze test (EPM). Method: Pregnant Wistar rats were randomly distributed into three groups according to the rearing condition. In the MS group, pups were separated daily from their dams for 180 minutes, from postnatal day (P) 2 to 14. In the SE group, two females that gave birth synchronously were housed in a cage with a litter of eight pups. Females from control standard housing (SH) were individually housed and kept with their offspring until weaning (P23). On P32, anxiety-related measures were evaluated using an EPM. Results: MS and SE increase anxiety-related behaviours and locomotion in rats exposed to the EPM. SE had sex-dependent effects on anxiety-related measures, increasing vertical activity in females and horizontal activity in males. MS but not SE increased body weight gain in female rats. Conclusion: Adverse or favourable rearing conditions early in life may result in an increased anxiety phenotype in the EPM during adolescence. It is likely that the favourable effect of SE depends on the number of dams per communal nest.

Resumen Introducción: Las condiciones de crianza adversas o favorables en etapas tempranas de la vida afectan la respuesta emocional durante la adolescencia. Para estudiar el efecto de la crianza temprana sobre la respuesta emocional, han sido útiles modelos animales como la separación materna (SM) y el enriquecimiento social (ES) mediante anidamiento comunitario. Sin embargo, se desconoce la comparación del efecto de la SM y el ES sobre las conductas relacionadas con la ansiedad en ratas adolescentes. Objetivo: Este estudio pretende evaluar los efectos de la SM y el ES sobre la respuesta emocional de ratas adolescentes expuestas al test del laberinto en cruz elevado (EPM). Método: Las ratas Wistar preñadas se distribuyeron aleatoriamente en tres grupos según la condición de crianza. En el grupo SM, las crías fueron separadas diariamente de sus madres durante 180 minutos, desde el día postnatal (P) 2 hasta el 14. En el grupo ES, dos hembras que parieron de forma sincronizada se alojaron en una caja con una camada de ocho crías. Las hembras del alojamiento estándar de control (SH) se alojaron individualmente y se mantuvieron con sus crías hasta el destete (P23). En P32, se evaluaron las medidas relacionadas con la ansiedad mediante un EPM. Resultados: La SM y el ES aumentan las conductas relacionadas con la ansiedad y la locomoción en las ratas expuestas al EPM. El ES tuvo efectos dependientes del sexo en las medidas relacionadas con ansiedad, aumentando la actividad vertical en las hembras y la actividad horizontal en los machos. La SM, pero no el ES, incrementó la ganancia de peso corporal en las ratas hembra. Conclusiones: Condiciones de crianza adversas o favorables en etapas tempranas de la vida pueden dar lugar a un fenotipo de ansiedad aumentado en el EPM durante la adolescencia. Es probable que el efecto favorable del ES dependa del número de hembras por nido comunitario.

Repeated Administration of a Full-Spectrum Cannabidiol Product, Not a Cannabidiol Isolate, Reverses the Lipopolysaccharide-Induced Depressive-Like Behavior and Hypolocomotion in a Rat Model of Low-Grade Subchronic Inflammation.

Background: Mounting evidence suggests that the phytocannabinoid cannabidiol (CBD) holds promise as an antidepressant agent in conditions underlined by inflammation. Full-spectrum CBD extracts might provide greater behavioral efficacy than CBD-only isolates and might require lower doses to achieve the same outcomes due to the presence of other cannabinoids, terpenes, and flavonoids. However, investigations in this area remain limited. Methods: We evaluated the behavioral response to the administration for 7 days of 15 and 30 mg/kg of a CBD isolate and a full-spectrum CBD product in a rat model of subchronic lipopolysaccharide (LPS, 0.5 mg/kg/day/7 days, intraperitoneal)-induced depressive-like and sickness behavior. The forced swim test was used to assess depressive-like behavior, the open field test (OFT) to assess locomotion, and the elevated plus maze to assess anxiety-like behavior. Results: The full-spectrum CBD extract at both doses, but not the CBD isolate, reversed the LPS-induced depressive-like behavior in the forced swim test. Moreover, the full-spectrum CBD extract at the higher dose but not the CBD isolate restored the subchronic LPS-induced hypolocomotion in the OFT. Repeated administration of both formulations elicited an anxiogenic-like trend in the elevated plus maze. Conclusion: Full-spectrum CBD products might have greater therapeutic efficacy in resolving inflammation-induced depressive and sickness behavior compared to a CBD-only isolate.

The anxiolytic-like effect of the alkaloid fraction of the psychedelic plant Mimosa tenuiflora (Willd.) Poir.

The present work investigated the anxiolytic effect of the alkaloid fraction (AF II) from the root bark of Mimosa tenuiflora. Female Swiss mice of 6 weeks old were used in this study. The animals were divided into three groups: 0.9% NaCl (vehicle group, s.c.), AF II (6 mg/kg, s.c.), and diazepam - DZP (5 mg/kg, s.c.). The light/dark box and elevated plus maze tests evaluated the animal anxiety. DMT was identified by the HPLC method. AF II showed significant anxiolytic effects in the two behavioural tests used.

Feuerstein Instrumental Enrichment Program for People With Schizophrenia After the First Episode of Psychosis: Protocol for an Open-Label Intervention Study.

BACKGROUND: Schizophrenia is a disorder associated with neurocognitive deficits that adversely affect daily functioning and impose an economic burden. Cognitive rehabilitation interventions, particularly during the early phases of illness, have been shown to improve cognition, functionality, and quality of life. The Feuerstein Instrumental Enrichment (FIE) program, based on the Mediated Learning Experience and the Structural Cognitive Modifiability theory, has been applied in various disorders, but its applicability in schizophrenia has not yet been clarified. OBJECTIVE: This study aims to investigate the effects of the FIE program on the functionality of patients with first-episode schizophrenia. METHODS: In total, 17 patients will be recruited for an open-label intervention consisting of twice-weekly sessions for 10 weeks. The primary outcome measure will be changes in the Goal Achievement Scale score. Maze task performance from the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) battery will serve as a secondary outcome measure. At the same time, changes in Positive and Negative Syndrome Scale scores and other MATRICS domains will be analyzed as exploratory outcomes. Assessments will be administered before and after the intervention, with a follow-up period of 6 months. RESULTS: This trial was preregistered in The Brazilian Registry of Clinical Trials (RBR-4gzhy4s). By February 2024, 11 participants were enrolled in the training. Recruitment is expected to be completed by May 2024. Data analysis will be conducted between May and September 2024. The results are expected to be published in January 2025. CONCLUSIONS: This study may establish a protocol for the FIE program that uses mediation techniques for individuals in the early stages of schizophrenia. The results will add to the knowledge about strategies to promote cognitive skills and functional impairment in daily life. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/57031.

Dihydroergotamine Increases Histamine Brain Levels and Improves Memory in a Scopolamine-Induced Amnesia Model.

The beneficial effects of increasing histamine levels on memory have acquired special interest due to their applicability to psychiatric conditions that cause memory impairments. In addition, by employing drug repurposing approaches, it was demonstrated that dihydroergotamine (DHE), an FDA drug approved to treat migraines, inhibits Histamine N Methyl Transferase (HNMT), the enzyme responsible for the inactivation of histamine in the brain. For this reason, in the present work, the effect of DHE on histamine levels in the hippocampus and its effects on memory was evaluated, employing the scopolamine-induced amnesia model, the Novel Object Recognition (NOR) paradigm, and the Morris Water Maze (MWM). Furthermore, the role of histamine 1 receptor (H1R) and histamine 2 receptor (H2R) antagonists in the improvement in memory produced by DHE in the scopolamine-induced amnesia model was evaluated. Results showed that the rats that received DHE (10 mg/kg, i.p.) showed increased histamine levels in the hippocampus after 1 h of administration but not after 5 h. In behavioral assays, it was shown that DHE (1 mg/kg, i.p.) administered 20 min before the training reversed the memory impairment produced by the administration of scopolamine (2 mg/kg, i.p.) immediately after the training in the NOR paradigm and MWM. Additionally, the effects in memory produced by DHE were blocked by pre-treatment with pyrilamine (20 mg/kg, i.p.) administered 30 min before the training in the NOR paradigm and MWM. These findings allow us to demonstrate that DHE improves memory in a scopolamine-induced amnesia model through increasing histamine levels at the hippocampus due to its activity as an HNMT inhibitor.

Inhibition of corticosterone synthesis impairs cued water maze consolidation, but it does not affect the expression of BDNF, CK2 and SGK1 genes in dorsal striatum.

Corticosterone (CORT) release during learning experiences is associated with strong memories and activity of the glucocorticoid receptor. It has been shown that lesions of the dorsal striatum (DS) of rats trained in the cued version of the Morris water maze impair memory, and that local injection of CORT improves its performance, suggesting that DS activity is involved in procedural memory which may be modulated by CORT. We trained rats in cued Morris water maze and analyzed the effect of CORT synthesis inhibition on performance, CORT levels, expression of plasticity-involved genes, such as the brain derived neurotrophic factor (BDNF), casein kinase 2 (CK2), and the serum/glucocorticoid regulated kinase 1 (SGK1), as well as the presence of phosphorylated nuclear glucocorticoid receptor in serine 232 (pGR-S232) in the DS. The inhibition of CORT synthesis by metyrapone reduced CORT levels in plasma, prevented its increment in DS and impaired the performance of cued water maze. Additionally, there was an increase of CK2 and SGK1 mRNAs expression in trained subjects, which was unrelated to CORT levels. Finally, we did not observe changes in nuclear pGR-S232 in any condition. Our findings agree with evidence demonstrating that decreasing CORT levels hinders acquisition and consolidation of the spatial version of the Morris water maze; these novel findings broaden our knowledge about the involvement of the DS in the mechanisms underlying procedural memory.

The influence of classical music on learning and memory in rats: a systematic review and meta-analysis.

During the learning process, music can activate important neural areas in the brain, promoting the retention of information and memory formation. However, studies testing music effects on memory had found different improvements, which could be due to the methodological differences across studies. Thus, the purpose of this article was to systematically review the literature and meta-analyze the effects of music on Rattus norvegicus' explicit memory (Maze tests) only in controlled investigations. The seven studies included led to a very homogeneous analysis (I2 = 0%), confirming the consistency of the significant standardized mean difference (SMD) between the memory of animals exposed and not exposed to music (SMD 0.60 (95% CI 0.38; 0.83, p < 0.001)). Exploratory analysis suggests music benefits on memory can be acquired when begun at any age, when tested with the three types of mazes evaluated, with exposure lasting from 8 to 83 days and when the age on test day was either under 30 days or over 30 days. To expand the actual understanding of music effects on memory, future studies should investigate different types of music and animal species, with different sex and health conditions, at different time points.

Forty-kHz ultrasonic vocalizations of rat pups predict adult behavior in the elevated plus-maze behavior but not the effect of cocaine on 50-kHz ultrasonic vocalizations.

Ultrasonic vocalizations (USV) are emitted by both young pups and adult rats to convey positive or negative emotional states. These USV manifestations are contingent on factors including developmental stage, situational requirements, and individual dispositions. Pups emit 40-kHz USV when separated from their mother and litter, which function to elicit maternal care. Conversely, adult rats can produce 50-kHz USV in response to stimuli that elicit reward-related states, including natural rewards, stimulant drugs, and reward-predictive stimuli. The present study aims to investigate whether pup 40-kHz USV can serve as predictors of behaviors related to positive or negative states in adult rats. Both male and female Wistar pups were initially tested on the 11th postnatal day and subsequently in adulthood. There was no significant difference in the number of 40-kHz ultrasonic vocalizations between male and female pups. However, cocaine elicited more 50-kHz USV and hyperactivity in adult females compared to males. Notably, cocaine increased the proportion of step and trill USV subtypes in both adult males and females. Interestingly, this effect of cocaine was stronger in females that were in the diestrus, compared to the estrus phase. In males, a significant positive correlation was found between pup 40-kHz USV and lower anxiety scores in adult male but not female rats tested on the elevated plus-maze test. Furthermore, no significant correlation was found between pup 40-kHz and adult 50-kHz USV in both males and females, whether in undrugged (saline) or in cocaine-treated rats. It is possible that the 40-kHz USV emitted by pups predicted reduced anxiety-like behavior only for male rats because they could elicit maternal care directed specifically to male pups. These findings suggest that 40-kHz USV can serve as an indicator of the emotional link between the rat mother and male pups. Indeed, this suggests that maternal care exerts a positive influence on the emotional state during adulthood.

Application of Cut-and-Sew Technique in Thoracoscopic Minimally Invasive Mitral Valve Surgery and Concomitant Maze Procedure

ABSTRACT Introduction: Atrial fibrillation is one of the common complications of mitral valve disease. Currently, in the absence of freezing equipment, it's still impossible to fully conduct a minimally invasive Cox-maze IV procedure to treat atrial fibrillation. Methods: We analyzed the clinical data of 28 patients who underwent thoracoscopic minimally invasive mitral valve full maze surgery in our hospital from October 2021 to September 2022; 13 patients were male and 15 were female, three suffered from paroxysmal atrial fibrillation, and 25 suffered from permanent atrial fibrillation; average age was 61.88±8.30 years, and mean preoperative left atrial diameter was 47.12±8.34 mm. Isolation of left atrial posterior wall (box lesion) was completed in all patients by cut-and-sew technique and bipolar clamp ablation. Results: For these subjects, the median cardiopulmonary bypass time was 169 (109.75-202.75) minutes, aortic cross-clamping time was 106 (77.75-125.50) minutes, and ventilator assistance time was 6.5 (0-10) hours. Among them, eight subjects had the endotracheal tubes removed immediately after surgical operation. Three subjects were in the blanking period; two subjects still had atrial fibrillation at three months after operation, one of whom resumed sinus rhythm after electrical cardioversion therapy; and all the remaining 23 subjects had sinus rhythm. Conclusion: The minimally invasive cut-and-sew technique for electrical isolation of left pulmonary veins can improve sinus conversion rate of patients suffering from both mitral valve disease and atrial fibrillation. In selected subjects, it is safe and has good results in the short-term postoperative period.

Application of Cut-and-Sew Technique in Thoracoscopic Minimally Invasive Mitral Valve Surgery and Concomitant Maze Procedure.

INTRODUCTION: Atrial fibrillation is one of the common complications of mitral valve disease. Currently, in the absence of freezing equipment, it's still impossible to fully conduct a minimally invasive Cox-maze IV procedure to treat atrial fibrillation. METHODS: We analyzed the clinical data of 28 patients who underwent thoracoscopic minimally invasive mitral valve full maze surgery in our hospital from October 2021 to September 2022; 13 patients were male and 15 were female, three suffered from paroxysmal atrial fibrillation, and 25 suffered from permanent atrial fibrillation; average age was 61.88±8.30 years, and mean preoperative left atrial diameter was 47.12±8.34 mm. Isolation of left atrial posterior wall (box lesion) was completed in all patients by cut-and-sew technique and bipolar clamp ablation. RESULTS: For these subjects, the median cardiopulmonary bypass time was 169 (109.75-202.75) minutes, aortic cross-clamping time was 106 (77.75-125.50) minutes, and ventilator assistance time was 6.5 (0-10) hours. Among them, eight subjects had the endotracheal tubes removed immediately after surgical operation. Three subjects were in the blanking period; two subjects still had atrial fibrillation at three months after operation, one of whom resumed sinus rhythm after electrical cardioversion therapy; and all the remaining 23 subjects had sinus rhythm. CONCLUSION: The minimally invasive cut-and-sew technique for electrical isolation of left pulmonary veins can improve sinus conversion rate of patients suffering from both mitral valve disease and atrial fibrillation. In selected subjects, it is safe and has good results in the short-term postoperative period.

Characterization of Depression- and Anxiety-Like Behaviours in a Mouse Model of Relapsing-Remitting Multiple Sclerosis.

Relapsing-remitting multiple sclerosis (RRMS) is an autoimmune neurological disease and is the most common subtype of MS. In addition, it is associated with the development of depression and anxiety. To date, depressive- and anxiety-like behaviours were only studied using models of progressive MS, which causes severe motor alterations. Thus, we sought to standardise the depressive and anxiety-like behaviours in an RRMS model induced by experimental autoimmune encephalomyelitis (RR-EAE) in mice. The RR-EAE model was induced in C57BL/6 female mice using myelin oligodendrocyte glycoprotein (MOG35-55) antigen and Quillaja saponin (Quil A) as an adjuvant. The immunisation of RR-EAE did not induce locomotor alteration but caused relapsing-remitting induction of clinical scores in mice until 35 post-immunization (p.i.). Also, increased levels of tumour necrosis factor alpha (TNF-α), astrocyte marker (GFAP), and microglial markers (IBA-1) were detected in the prefrontal cortex at 35 p.i. of RR-EAE. In the open field test, RR-EAE mice showed decreased time spent at the centre and sniffing behaviour (at days 21 and 34 p.i.). Also, on day 35 p.i. the RR-EAE group spent less time in the open arms and had decreased open-arm entries compared to control mice in the elevated plus maze (EPM) test, confirming the anxiety-like behaviour. At day 36° p.i. in the tail suspension test, mice showed depression-like behaviour with decreased latency time and increased immobility time. Thus, the RR-EAE model mimics the neuroinflammatory and behavioural features of the RRMS, including depression- and anxiety-like symptoms.

Automating behavioral analysis in neuroscience: Development of an open-source python software for more consistent and reliable results.

BACKGROUND: The application of automated analyses in neuroscience has become a practical approach. With automation, the algorithms and tools employed perform fast and accurate data analysis. It minimizes the inherent errors of manual analysis performed by a human experimenter. It also reduces the time required to analyze a large amount of data and the need for human and financial resources. METHODS: In this work, we describe a protocol for the automated analysis of the Morris Water Maze (MWM) and the Open Field (OF) test using the OpenCV library in Python. This simple protocol tracks mice navigation with high accuracy. RESULTS: In the MWM, both automated and manual analysis revealed similar results regarding the time the mice stayed in the target quadrant (p = 0.109). In the OF test, both automated and manual analysis revealed similar results regarding the time the mice stayed in the center (p = 0.520) and in the border (p = 0.503) of the field. CONCLUSIONS: The automated analysis protocol has several advantages over manual analysis. It saves time, reduces human errors, can be customized, and provides more consistent information about animal behavior during tests. We conclude that the automated protocol described here is reliable and provides consistent behavioral analysis in mice. This automated protocol could lead to deeper insight into behavioral neuroscience.

A new automatic method for tracking rats in the Morris water maze.

Morris water maze (MWM) test is widely used to evaluate the learning and memory deficits in rodents. Image processing and pattern recognition can be used to analyse videos and recognize automatically the tracking in MWM. There are several commercial and free access software that allows analyzing the behavioral tasks although they also have limitations such as automation, cost, user intervention among other things. The aim of this paper was to develop a new image processing technique to automatically analyse the track of the rat in the MWM, which we called RatsTrack. The MWM test was performed with an animal model for Alzheimer, and the videos were recorded to measure the distance, time, and speed. The segmentation method based on the projection of the video frames was made for pool identification, eliminating the rat, while conserving the shape of the pool. Then, the Hough transformation was used to recognize the position and radius of the pool. Finally, the frame in which the rat is released into the pool was established automatically using mathematical morphology techniques and added as a plugin on free access ImageJ software. The new image processing technique, RatsTrack, successfully detected and located the pool and rat without user intervention, significantly decreasing operational time and providing results for distance, time, speed, and acceleration parameters of the MWM test. Alzheimer's rats compared with the control group presented significant data measured with the RatsTrack. RatsTrack is a plugin of ImageJ software and will be made freely available for public use.

The antipsychotic olanzapine reduces memory deficits and neuronal abnormalities in a male rat model of Autism.

The prevalence of autism spectrum disorder (ASD), a neurodevelopmental condition that impacts social interaction and sensory processing, is rising. Valproic acid (VPA) exposure during pregnancy causes autistic-like traits in offspring. Olanzapine (OLZ), an atypical antipsychotic, is used to treat ASD. We assessed the impact of OLZ on behavior, neuromorphology, and nitric oxide (NO) levels in the hippocampus using prenatal VPA treatment in rats. It is commonly known that ASD patients exhibit sensory abnormalities. As such, we utilized the tail flick test to validate the ASD model. In the novel object recognition test (NORT), VPA exposure reduces the discrimination index (DI) in the first introduction to the novel object. Moreover, OLZ and vehicle-treated rats perform differently in the second exposition to the DI of the novel object, suggesting that OLZ reverses VPA-induced deficits in recognition memory. The latency to find the hidden platform in the Morris water maze test of memory and learning improves in VPA-exposed rats after OLZ administration, indicating that OLZ improves spatial memory in these rats. Administration of prenatal VPA induces neuronal hypotrophy and reduces spine density in pyramidal neurons of the CA1 region of the hippocampus. Treatment with OLZ corrects the neuromorphological changes brought on by VPA. In the CA1 region of the hippocampus, VPA treatment increases the number of neurons, which normalizes with OLZ treatment. OLZ increases the NO levels in the dorsal hippocampus in control rats. In rats exposed to VPA, the second-generation antipsychotic OLZ reduces memory-related and neuroplastic alterations. The current findings support the use of OLZ in this illness and further validate the use of prenatal VPA as a model of ASD.

The insula mediates the effects of glucocorticoids in anxiety.

Increased activity in the insula has been consistently reported to be associated with anxiety and anxiety-related disorders. However, little is known on how the insula regulates anxiety. The present study aims at determining the role of the insula on the effects of glucocorticoids in anxiety. A combination of pharmacological manipulations, including blockade of adrenal GC synthesis by metyrapone and intra-insular microinjections of corticosterone, corticosterone-BSA, mineralocorticoid receptor (MR) antagonist spironolactone and glucocorticoid receptor (GR) antagonist mifepristone, were used to assess the short-term (5 min) effects of intra-insular corticosterone in two anxiety-like behaviors in male Sprague-Dawley rats. The elevated plus maze (EPM) and Novelty Suppressed Feeding (hyponeophagia) were utilized. We found that corticosterone in the insula is sufficient to prevent the anxiolytic effects corticosterone synthesis blockade in anxiety, and that intra-insular corticosterone has anxiolytic or anxiogenic effects depending on the amount of corticosterone microinjected and the arousal associated to the test, without affecting the HPA axis. Glucocorticoid anxiolytic effects in the insula are mediated by MRs, while its anxiogenic effects are dependent on a mifepristone-sensitive membrane-bound mechanism. Anxiety appears to be modulated at the insula through a competition between fast MR-dependent anxiolytic and membrane-associated anxiogenic signaling pathways that orchestrate the behavioral response to stress and determines the resulting level of anxiety.

Neonatal olfactory bulbectomy induces anxiety-related behavior and modifies dopaminergic receptor expression in post-pubertal rats.

Olfaction is a complex physiological process producing effects in the central nervous system (CNS) and implicated in emotional processes. Indeed, the olfactory bulbs (OB) send projections to various CNS regions including the nucleus accumbens (NAcc) and caudate-putamen (CPu). Both the NAcc and CPu receive important dopaminergic input. Emerging evidence suggests that dopamine (DA) is related to anxiety-related behaviors. Therefore, we aimed to investigate the consequences of neonatal olfactory bulbectomy (nOBX) to anxiety-related behavior as assayed in the elevated plus maze (EPM) as well as the expression of dopaminergic receptors (D1-like, D2-like, and D3) in the NAcc and CPu at pre- and post-pubertal ages in the rat. The results show that nOBX increased the number of entries in the open arm of the EPM post-pubertally, suggesting an anxiolytic-related effect. nOBX increased the D2-like binding in the NAcc shell and D3 binding in the NAcc core pre-pubertally. At post-pubertal ages, the D3 binding was reduced at the olfactory tubercle and islands of Calleja in nOBX rats. Alterations in the DA receptor expression may be one mechanism responsible for the observed behavioral modifications in nOBX rats.

The Estrous Cycle Influences the Effects of Fatty Acid Amide Hydrolase and Monoacylglycerol Lipase Inhibition in the Anxiety-Like Behavior in Rats.

Background: Sex differences in the response to the anxiety-related effects of cannabinoid drugs have been reported, with females being more sensitive than males. Evidence suggests that, according to sex and estrous cycle phase (ECP), the content of the endocannabinoids (eCBs) N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG) varies in brain areas involved in the anxiety-like behavior. Methods: Considering the lack of studies evaluating sex and ECP differences in the eCB system in anxiety, using URB597, a fatty acid amide hydrolase inhibitor, or MJN110, a monoacylglycerol lipase inhibitor, we explored the effects of increasing AEA or 2-AG levels, respectively, in cycling and ovariectomized (OVX) female adult Wistar rats, as well as males, subjected to the elevated plus maze. Results: The administration of URB597 (0.1 or 0.3mg/kg; intraperitoneally) either increased or reduced the percentage of open arms time (%OAT) and open arms entries (%OAE), being anxiolytic in diestrus and anxiogenic in estrus. No effects were observed in proestrus or when all ECPs were analyzed together. Both doses produced anxiolytic-like effects in males. In OVX females, the anxiolytic-like effect of URB597 0.1 was associated with low levels of estradiol, whereas the anxiogenic-like effect of URB597 0.3 was spared by estradiol pretreatment. The systemic administration of MJN110 3.0 mg/kg reduced the risk assessment behavior (RAB), suggesting an anxiolytic-like effect independent of the ECP. When considering the ECP, MJN110 3.0 increased the %OAT and reduced the RAB, being anxiolytic in estrus and diestrus. No effects were observed in proestrus. Both doses of MJN110 were anxiogenic in males. In OVX females, the anxiolytic-like effect of MJN110 was dependent on low estradiol levels. Conclusion: Together, our findings support the evidence that females react differently to the effects of cannabinoids in the anxiety-like behavior; in addition, AEA and 2-AG modulation elicits anxiety-like responses that are closely influenced by hormone levels, mainly estradiol.

Systematic review on the anxiolytic and hypnotic effects of flower extracts in in vivo pre-clinical studies published from 2010 to 2020.

Anxiety disorders are prevalent conditions in the world population, whose standard approaches include pharmacotherapy, psychotherapy, and combinations of these interventions. Different classes of psychopharmaceuticals are recommended as the first line of drugs to treat these disorders, which can have several adverse effects, treatment resistance, dependence, and drug-drug interactions making it necessary to search for new therapeutic agents. In particular, diazepam (DZP), a prototype drug from the group of benzodiazepines, has been commonly used and evaluated for its efficacy and safety in different anxiety disorders in clinical trials. DZP is also the most widely used reference standard in in vivo pharmacological assays of natural compounds. However, translating the results obtained in different rodent species and physiological anxiety tests instead of psychopathological animal models that can be of clinical application remains challenging. A systematic review of scientific articles published between 2010 and 2020 that included in vivo pre-clinical tests to define the anxiolytic, sedative and/or hypnotic effect of flower extracts is proposed. PRISMA and Rayyan were used for the selection of studies using four databases (Pubmed, Scopus, Web of Science, and QInsight), using the keywords: "Animals," "Anxiolytic," "Diazepam," "Elevated Plus Maze," "Flower Extracts," "Insomnia," "In vivo," "Mice," "Open Field Test," "Pre clinical" and "Sedative." The characteristics of anxiety studies in animal models, other studies related to locomotor activity, and the hypnotic effect of the extracts were compiled. Twenty-four articles were included, 21 of them performed the animal model of anxiety-like behavior of the elevated plus maze, seven the open field test, and six the light-dark box test. The locomotor activity was evaluated in 10 studies after the administration of the extracts to the animals to define their sedative effect, where only one defined that the extract (Matricaria chamomilla) had a sedative effect. The plants declared with this type of activity were Achyranthes aspera, Alcea aucheri, Brassica nigra, Cananga odorata, Carthamus tinctorius, Chrysanthemum indicum, Citrus aurantium, Couroupita guianensis, Echium amoenum, Erythrina berteroana, Gardenia jasminoides, Hibiscus tilliaceus, Lavandula officinalis, Lawsonia inermis, Matricaria chamomilla, Melia azedarach, Nerium oleander, Passiflora incarnata, Plumeria rubra, Salix aegyptiaca, Syzygium aromaticum, Tagetes erecta, Tilia americana. Although this review showed that some flower extracts have an anxiolytic effect as effective as diazepam, their therapeutic utility in anxiety disorders remains to be extensively demonstrated. Hence, more reliable and predictive behavioral tests and appropriate strategies for the experimental designs are needed to obtain more conclusive evidence with clinical significance.

Long-term potentiation and spatial memory training stimulate the hippocampal expression of RyR2 calcium release channels.

Introduction: Neuronal Ca2+ signals generated through the activation of Ca2+-induced Ca2+ release in response to activity-generated Ca2+ influx play a significant role in hippocampal synaptic plasticity, spatial learning, and memory. We and others have previously reported that diverse stimulation protocols, or different memory-inducing procedures, enhance the expression of endoplasmic reticulum-resident Ca2+ release channels in rat primary hippocampal neuronal cells or hippocampal tissue. Methods and Results: Here, we report that induction of long-term potentiation (LTP) by Theta burst stimulation protocols of the CA3-CA1 hippocampal synapse increased the mRNA and protein levels of type-2 Ryanodine Receptor (RyR2) Ca2+ release channels in rat hippocampal slices. Suppression of RyR channel activity (1 h preincubation with 20 µM ryanodine) abolished both LTP induction and the enhanced expression of these channels; it also promoted an increase in the surface expression of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluR1 and GluR2 and caused a moderate but significant reduction of dendritic spine density. In addition, training rats in the Morris water maze induced memory consolidation, which lasted for several days after the end of the training period, accompanied by an increase in the mRNA levels and the protein content of the RyR2 channel isoform. Discussion: We confirm in this work that LTP induction by TBS protocols requires functional RyR channels. We propose that the increments in the protein content of RyR2 Ca2+ release channels, induced by LTP or spatial memory training, play a significant role in hippocampal synaptic plasticity and spatial memory consolidation.

Comparative analysis between Open Field and Elevated Plus Maze tests as a method for evaluating anxiety-like behavior in mice.

Anxiety is being increasingly diagnosed in the elderly population. In this sense, epidemiologic data have linked late-life anxiety disorders to increased cognitive decline, morbidity, and even mortality. In addition, studies have already reported the influence of the environment on the association between aging and anxiety. Therefore, the present study aimed to conduct a comparative analysis between Elevated Plus Maze (EPM) and Open Field (OF) tests as methods for evaluating mice's anxiety-like behavior, considering environmental and age variables. For this, eighty Female albino Swiss mice aged 6, 12, and 18 months were housed in an impoverished environment (IE) and enriched environment (EE). Following this, the animals were tested in EPM and OF tests. The environment and age affect the anxiety-like behavior of the mice in the OF, with a difference between the animals of 6 and 18 months, only in the EE (p < 0.021). However, in the EPM, it does not occur. Despite that, the environment affected the distance traveled by the mice in the EPM, where the IE animals showed greater exploratory activity than the EE, only in the 18-month group (p < 0.001). No environmental influences were detected in the OF. Concerning age, in the EPM, animals in the 18-month-old group traveled shorter distances compared to the 6-month group (p < 0.001) and the 12-month group (p < 0.001), only in EE. In turn, in the OF there was a decrease in the distance traveled in the 18-month group compared to the 6-month group (p = 0.012), only in the IE. Thus, the divergences between the results of EPM and OF instigate a better evaluation of the parameters analyzed in each test.