Effects In Female Mice Research Articles

Fasting produces antidepressant-like effects via activating mammalian target of rapamycin complex 1 signaling pathway in ovariectomized mice.

Recent studies have shown that a 9-hour fast in mice reduces the amount of time spent immobile in the forced swimming test. However, whether 9-hour fasting has therapeutic effects in female mice with depressive symptoms has not been established. Therefore, in this study, we simulated perimenopausal depression via an ovariectomy in mice, and subjected them to a single 9-hour fasting 7 days later. We found that the ovariectomy increased the time spent immobile in the forced swimming test, inhibited expression of the mammalian target of rapamycin complex 1 signaling pathway in the hippocampus and prefrontal cortex, and decreased the density of dendritic spines in the hippocampus. The 9-hour acute fasting alleviated the above-mentioned phenomena. Furthermore, all of the antidepressant-like effects of 9-hour fasting were reversed by an inhibitor of the mammalian target of rapamycin complex 1. Electrophysiology data showed a remarkable increase in long-term potentiation in the hippocampal CA1 of the ovariectomized mice subjected to fasting compared with the findings in the ovariectomized mice not subjected to fasting. These findings show that the antidepressant-like effects of 9-hour fasting may be related to the activation of the mammalian target of the rapamycin complex 1 signaling pathway and synaptic plasticity in the mammalian hippocampus. Thus, fasting may be a potential treatment for depression.

Neonatal exposure to ultrafine iron but not combined iron and sulfur aerosols recapitulates air pollution-induced impulsivity in mice

Air pollution (AP) is becoming recognized as a major threat to neurological health across the lifespan with increased risk of both neurodevelopmental and neurodegenerative disorders. AP is a complex mixture of gases and particulate matter, with adsorbed contaminants including metals and trace elements, which may differentially contribute to its neurodevelopmental impacts. Iron (Fe) is one of the most abundant metals found in AP, and Fe concentrations may drive some behavioral deficits observed in children. Furthermore, brains of neonate mice exposed to concentrated ambient ultrafine particulate matter (UFP) show significant brain accumulation of Fe and sulfur (S) supporting the hypothesis that AP exposure may lead to brain metal dyshomeostasis. The current study determined the extent to which behavioral effects of UFP, namely memory deficits and impulsive-like behavior, could be recapitulated with exposure to Fe aerosols with or without concomitant SO2. Male and female neonate mice were either exposed to filtered air or spark discharge-generated ultrafine Fe particles with or without SO2 gas (n = 12/exposure/sex). Inhalation exposures occurred from postnatal day (PND) 4–7 and 10–13 for 4 hr/day, mirroring our previous UFP exposures. Mice were aged to adulthood prior to behavioral testing. While Fe or Fe + SO2 exposure did not affect gross locomotor behavior, Fe + SO2-exposed females displayed consistent thigmotaxis during locomotor testing. Neither exposure affected novel object memory. Fe or Fe + SO2 exposure produced differential outcomes on a fixed-interval reinforcement schedule with males showing higher (Fe-only) or lower (Fe + SO2) response rates and postreinforcement pauses (PRP) and females showing higher (Fe-only) PRP. Lastly, Fe-exposed, but not Fe + SO2-exposed, males showed increased impulsive-like behavior in tasks requiring response inhibition with no such effects in female mice. These findings suggest that: 1) exposure to realistic concentrations of Fe aerosols can recapitulate behavioral effects of UFP exposure, 2) the presence of SO2 can modulate behavioral effects of Fe inhalation, and 3) brain metal dyshomeostasis may be an important factor in AP neurotoxicity.

Rhamnan sulfate reduces atherosclerotic plaque formation and vascular inflammation

ObjectiveWhile lipid-lowering drugs have become a mainstay of clinical therapy these treatments only slow the progression of the disease and can have side effects. Thus, new treatment options are needed to supplement the effects of lipid lowering therapy for treating atherosclerosis. We examined the use of an inexpensive and widely available marine polysaccharide rhamnan sulfate as an oral therapeutic for limiting vascular inflammation and atherosclerosis. Methods and resultsWe found rhamnan sulfate enhanced the barrier function of endothelial cells, preventing the deposition of LDL and maintaining barrier function even in the presence of glycocalyx-degrading enzymes. Rhamnan sulfate was also found to bind directly to FGF-2, PDGF-BB and NF-κB subunits with high affinity. In addition, rhamnan sulfate was a potent inhibitor of NF-κB pathway activation in endothelial cells by TNF-α. We treated ApoE−/− mice with a high fat diet for 4 weeks and then an addition 9 weeks of high fat diet with or without rhamnan sulfate. Rhamnan sulfate reduced vascular inflammation and atherosclerosis in both sexes of ApoE−/− mice but had a stronger therapeutic effect in female mice. Oral consumption of rhamnan sulfate induced a significant decrease in cholesterol plasma levels in female mice but not in male mice. In addition, there was a marked reduction in inflammation for female mice in the liver and aortic root in comparison to male mice. ConclusionsRhamnan sulfate has beneficial effects in reducing inflammation, binding growth factors and NF-κB, enhancing endothelial barrier function and reducing atherosclerotic plaque formation in ApoE−/− mice.

Peroxisome Proliferator-Activated Receptor α Has a Protective Effect on Fatty Liver Caused by Excessive Sucrose Intake.

Sterol regulatory element binding protein (SREBP)-1c is a transcription factor that regulates lipid synthesis from glucose in the liver. It is activated by sucrose, which activates the fatty acid synthesis pathway. On the other hand, peroxisome proliferator-activated receptor (PPAR) α regulates the transcription of several genes encoding enzymes involved in fatty acid β-oxidation in the liver. To evaluate the beneficial effects of PPARα on fatty liver caused by excessive sucrose intake, we investigated the molecular mechanisms related to the development of fatty liver in PPARα-deficient mice that were fed a high-sucrose diet (Suc). The SREBP-1c target gene expression was increased by sucrose intake, leading to the development of fatty liver. Furthermore, PPARα−/− mice developed severe fatty liver. Male and female PPARα−/− mice fed Suc showed 3.7- and 3.1-fold higher liver fat content than Suc-fed male and female wild-type mice, respectively. Thus, PPARα may work to prevent the development of fatty liver caused by excessive sucrose intake. Liver TG accumulation differed between male and female PPARα−/− mice. A possible explanation is that male mice show the increased expression of Pparγ, which usually contributes to triglyceride synthesis in the liver, to compensate for Pparα deficiency. In contrast, female wild-type mice inherently have low Pparα levels. Thus, Pparα deficiency has less pronounced effects in female mice. A diet that activates PPARα may be effective for preventing the development of fatty liver due to excessive sucrose intake.

Nose-Only Exposure to Cherry- and Tobacco-Flavored E-Cigarettes Induced Lung Inflammation in Mice in a Sex-Dependent Manner.

Flavoring chemicals in electronic nicotine delivery systems have been shown to cause cellular inflammation; meanwhile, the effects of fruit and tobacco flavors on lung inflammation by nose-only exposures to mice are relatively unknown. We hypothesized that exposure to flavored e-cigarettes would cause lung inflammation in C57BL/6 J mice. The mice were exposed to air, propylene glycol/vegetable glycerin, and flavored e-liquids: Apple, Cherry, Strawberry, Wintergreen, and Smooth & Mild Tobacco, one hour per day for three days. Quantification of flavoring chemicals by proton nuclear magnetic resonance spectroscopy (1H NMR), differential cell counts by flow cytometry, pro-inflammatory cytokines/chemokines by ELISA, and matrix metalloproteinase levels by western blot were performed. Exposure to PG/VG increased neutrophil cell count in lung bronchoalveolar lavage fluid (BALF). KC and IL6 levels were increased by PG/VG exposure and female mice exposed to Cherry flavored e-cigarettes, in lung homogenate. Mice exposed to PG/VG, Apple, Cherry, and Wintergreen increased MMP2 levels. Our results revealed flavor- and sex-based e-cigarette effects in female mice exposed to cherry-flavored e-liquids and male mice exposed to tobacco-flavored e-liquids, namely, increased lung inflammation.

Mammalian social memory relies on neuromodulation in the olfactory bulb

Abstract In this review, we aim to integrate our recent findings on the vasopressin system and its role in social discrimination with other known neuromodulatory mechanisms in the olfactory bulb that are involved in different experimental models of social memory. Behavioral paradigms commonly used to investigate odor-related social memory are individual social memory in rodents, lamb recognition in sheep, and the Bruce effect in female mice. All three cases involve neuromodulation in the main and/or the accessory olfactory bulb, the first centers for olfactory processing. As a large diversity of neuromodulators participate in social memory formation, here, we focus primarily on shared neuromodulatory systems and their physiological effects, in particular, the social neuropeptides, vasopressin and oxytocin, and the arousal-related modulators, acetylcholine and noradrenaline.

Effects of a High Glycemic Diet and Soluble Epoxide Hydrolase Inhibitor on Hippocampal Microvascular Function, and Multigenomic Modifications

ObjectivesDiet is a modifiable risk factor for cardiovascular disease (CVD) and dementia, yet relatively little is known about the effect of a high glycemic diet (HGD) on the brain microvasculature. The objective of our study was to determine the multigenomic effects of a HGD on hippocampal microvessels, and to determine if a soluble epoxide hydrolase (sEH) inhibitor (sEHI), known to be vasculoprotective and anti-inflammatory, modulates these effects.MethodsWild type male and female mice were fed a low glycemic diet (LGD, 12% sucrose/weight) or a HGD (34% sucrose/weight) with/without the sEHI, trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB), for 12 wks. Brain hippocampal microvascular gene expression was assessed by microarray and data analyzed using a multiomic approach for differential expression of protein and non-protein coding genes, gene networks, functional pathways, and transcription factors.ResultsGlobal hippocampal microvascular gene expression was fundamentally different for mice fed the HGD vs the LGD. The HGD modulated expression of genes involved in cell signaling, neurodegeneration, metabolism, and cell adhesion/inflammation/oxidation effects reversible by t-AUCB and hence sEH inhibitor correlated with protection against Alzheimer's dementia. However, in female, HGD had very minor genomic modifications, while sEHI presented significant effect in female mice on LGD.ConclusionsOurs is the first study to demonstrate that high dietary glycemia contributes to brain hippocampal microvascular inflammation, through sEH, effects that were sex-dependant.Funding SourcesThis work was supported by an award from the Richard A. and Nora Eccles Foundation (A20-0111), the Richard A. and Nora Eccles Harrison Endowed Chair in Diabetes Research (J.C.R.), and the Frances Lazda Endowed Chair in Women's Cardiovascular Medicine (A.C.V).

Elucidating the Role of Testosterone in the Descending Pain Pathway after Activity-induced Pain

We developed an activity-induced musculoskeletal pain model that produces behavioral sex differences in which females develop widespread hyperalgesia of longer duration, while males develop localized pain for shorter durations. Previously, we determined that testosterone mediates the behavioral phenotype in male and female mice, and that there are sex-dependent differences in expression of SERT in the RVM with females showing increased expression. The current study examined the role of RVM in mediating the testosterone-dependent behavioral phenotype and SERT expression. The pain model was induced by two injections (pH 5.0 saline) into the left gastrocnemius muscle combined with 6 minutes of fatiguing muscle contraction. Hyperalgesia was tested with withdrawal threshold of the gastrocnemius using force sensitive tweezers. To determine if testosterone mediates antinociception centrally, we implanted a guide cannula into the RVM and microinjected drugs to modulate sex hormone receptors in male and female mice. We also tested whether systemic changes in sex hormones modulated SERT in the RVM and whether blockade of SERT in the RVM modulates pain behavior. Blockade of either estrogen receptors (p<.01) or aromatase (p<.05) in the RVM resulted in contralateral hyperalgesia in male mice but had no effect in female mice (p=.457). In females, activation of androgen receptors with dihydrotestosterone reversed the behavioral phenotype causing unilateral hyperalgesia (p<.05). Also, systemic testosterone reduced the increased SERT expression in the RVM in female mice (p=.009); there was no change in gonadectomized males (p=.915). Microinjection of a SERT inhibitor into the RVM reversed ipsilateral hyperalgesia in both male (p<.05) and female (p<.05) mice. Our data suggests that males convert testosterone in the RVM to estrogen to protect from development of widespread hyperalgesia. Conversely, activation of androgen receptors in the RVM in female mice leads to antinociception which may be through modulation of SERT expression. Grant support from AR073187.

Latent Sex Differences in CaMKII-nNOS Signaling That Underlie Antidepressant-Like Effects of Yueju-Ganmaidazao Decoction in the Hippocampus.

Previous studies have demonstrated that Yueju-Ganmaidazao (YG) decoction induces rapid antidepressant-like effects, and the antidepressant response is mostly dependent on the suppression of nitric oxide-cyclic guanosine monophosphate signaling in male mice. This study aimed to investigate the sex difference mediated by calcium/calmodulin-dependent protein kinase II (CaMKII)-neuronal nitric oxide synthase (nNOS) signaling involved in the antidepressant-like effect of YG in mice. We found that the immobility times in the tail suspension test (TST) were found to be decreased after the single injection of YG in male and female mice with the same dosage. Additionally, chronic administration for 4 days of subthreshold dosage of YG and escitalopram (ES) also significantly decreased the immobility time in mice of both sexes. Chronic subthreshold dosage of YG and ES in LPS-treated mice and in chronic unpredictable stress (CUS) mice both decreased the immobility time, which was increased by stress. Meanwhile, in CUS-treated mice, sucrose preference test, forced swimming test, and open field test were applied to further confirm the antidepressant-like effects of YG and ES. Moreover, CUS significantly decreased the expression of nNOS and CaMKII, and both YG and ES could enhance the expression in the hippocampus of female mice, which was opposite to that in male mice, while endothelial nitric oxide synthase expression was not affected by stress or drug treatment neither in male mice nor in female mice. Finally, subthreshold dosage of YG combined with 7-nitroindazole (nNOS inhibitor) induced the antidepressant-like effects both in female and in male mice, while the single use of YG or 7-NI did not display any effect. However, pretreatment with KN-93 (CaMKII inhibitor) only blocked the antidepressant-like effect of high-dosage YG in female mice. Meanwhile, in CUS mice, chronic stress caused NR1 overexpression and inhibited cAMP response element binding protein action, which were both reversed by YG and ES in male and female mice, implying that YG and ES produced the same antidepressant-like effect in mice of both sexes. The study revealed that chronic treatment with a subthreshold dose of YG also produced antidepressant-like effects in female mice, and these effects depended on the regulation of the CaMKII-nNOS signaling pathway.

Sex differences in cholinergic regulation of dopamine release mechanisms underlying reward learning

Substance use disorder (SUD) is a chronic, recurring brain disease characterized by significant dysfunction in reward-seeking behavior. SUD research focused on understanding the neural mechanisms in the brain's reward circuitry has overwhelmingly utilized male subjects, even though epidemiological evidence shows that women are the most susceptible population. The neural control of reward is dependent on tonic/phasic dopamine release in the NAc that are subject to heavy modulation by cholinergic interneurons (ChATs) signaling through nicotinic acetylcholine receptors (nAChRs) located directly on dopamine terminals; a process that is essential to encoding information about environmental reward predictive cues. Importantly, dopamine release in the NAc can be elicited completely independent of action potential firing from the soma – through activation of α4β2*-containing nAChRs located on dopamine terminals - highlighting the critical role that this local microcircuit plays in controlling dopamine neurotransmission. Previous work suggests that ChAT control of reward learning and regulation of dopamine release through nAChRs is fundamentally different between males and females, yet the reward information encoding processes and mechanisms that underlie sex differences in reward learning are largely unknown. To understand how the neural circuits that underlie reward learning are differentially modulated between males and females, we took a multifaceted approach to outlining sex differences in ChAT regulation of tonic/phasic dopamine release mechanisms through nAChR modulation in the NAc. Using fast-scan cyclic voltammetry paired with pharmacology we measured the potentiating effect of 17β-estradiol with and without application of the selective α4β2-nAChR antagonist, Dhβe, on sub-second tonic/phasic dopamine release in NAc slices from male and naturally cycling female mice. First, we found that 17β-estradiol enhanced tonic dopamine release in both sexes with greater biological effects in males. Additionally, 17β-estradiol potentiated dopamine release in response to phasic stimulation patterns in males with no significant effect in females. To investigate how ovarian activity affects the ability of 17β-estradiol to potentiate tonic/phasic dopamine release, ovariectomized females were utilized, showing a similar potentiating effect of 17β-estradiol on tonic/phasic dopamine release as seen in the males. Finally, blocking α4β2*-nAChRs with Dhβe reduced the potentiating effects of 17β-estradiol on dopamine release in males and ovariectomized females, but had no effect in female mice with intact ovaries. This data suggests that circulating ovarian hormones alter the effect of α4β2*-nAChRs on dopamine terminals to regulate dopamine release in the NAc. Moving forward, it will be critical to directly link these sex differences to reward learning for the development of sex-specific pharmacotherapies to treat SUD.

Effects of (+)-naloxone blocking Toll-like Receptor 4 in depression and cognition

Abstract The immune system has been shown to affect the brain, and consequently behaviors. In particular, increasing evidence indicates that inflammation contributes to susceptibility to depression, which is a leading cause of disability, and for which current treatments are often inadequate. We hypothesized that targeting Toll-like receptor 4 (TLR4), one of the main signaling pathways for triggering an inflammatory response, would lessen stress-induced depression-like behaviors in mice. TLR4 inhibition with the CNS-penetrating drug (+)-naloxone that is a TLR4 antagonist but is inactive at opiate receptors, reversed chronic restraint stress-induced impairments of various depression-like behaviors, as well as cognitive tests in male mice but had no effect in female mice. These effects might be mediated by interferon-β (IFNβ) pathway in microglial cells. Altogether, our results confirmed the critical role of TLR4 in mediating depressive-like behaviors and cognitive impairments and demonstrated that (+)-naloxone might be a promising therapeutic strategy for depression.

Manipulations of the gut microbiome alter chemotherapy-induced inflammation and behavioral side effects in female mice

Chemotherapy treatment is associated with acute behavioral side effects (fatigue, anorexia) that significantly reduce patient quality of life and are dose-limiting, thereby increasing mortality (Kidwell et al., 2014). Disruptions to gut homeostasis (diarrhea, constipation, microbial dysbiosis) are also observed in patients receiving chemotherapy. In non-oncological patients, facets of mental health (fatigue, anxiety, depression) correlate with alterations in the gut microbiome, suggestive of a contribution of the gut in CNS disease etiology. The potential gut-to-brain pathway is poorly understood in patients receiving chemotherapy. Our prior studies have demonstrated a correlation between chemotherapy treatment, gut changes, peripheral and central inflammation, and behavioral symptoms in mice. Here we aimed to determine the extent to which chemotherapy-associated gut manipulations modulate the behavioral and biological consequences of chemotherapy. We measured sickness behaviors, peripheral and central inflammatory mediators, and anxiety in conventional or germ-free female mice: 1) cohabitating with mice of the opposite treatment group, 2) pre-treated with broad-spectrum antibiotics, or 3) given an intra-gastric gavage of gut content from chemotherapy-treated mice. In cohabitation studies, presumed coprophagia promoted body mass recovery, however strong associations with inflammation and behavior were not observed. Reduction of gut microbial alpha diversity via antibiotics did not prevent chemotherapy-associated side effects, however the relative abundances of the genera Tyzzerella, Romboutsia, and Turicibacter correlated with circulating inflammatory (IL-1β) and behavioral outcomes (lethargy, anxiety-like behavior). A gut microbiota transplant from chemotherapy-treated mice decreased central locomotion in open field testing, increased circulating CXCL1, and increased hippocampal Il6 and Tnfa in germ-free mice compared to germ-free mice that received a transplant from vehicle-treated mice. Taken together, these data provide further evidence that the gut microbiota likely contributes to the development of chemotherapy-associated side effects. This work has significant implications in the future treatment of anxiety in patients, and warrants future studies using microbe-based treatment options.

Effects of in utero and lactational exposure to the no-observed-adverse-effect level (NOAEL) dose of the neonicotinoid clothianidin on the reproductive organs of female mice.

Recently, developmental exposure to clothianidin (CLO) has been shown to cause reproductive toxicity in male mice, but the effects in female mice remain to be clarified. Pregnant C57BL/6N mice were given a no-observed-adverse-effect-level (NOAEL) dose of CLO until weaning. We then examined ovaries of 3- or 10-week-old female offspring. In the CLO-administered group, morphological changes, a decrease in the immunoreactivity of the antioxidant enzyme glutathione peroxidase 4 (GPx4), and activation of genes in the steroid hormone biosynthesis pathway were observed in 3-week-old mice, and decreases of GPx4 immunoreactivity, 17OH-progesterone and corticosterone levels were observed in 10-week-old mice, along with high rates of infanticide and severe neglect, providing new evidence that developmental exposure to CLO affects juvenile and adult mice differently.

Sex-dependent variations in anti-nociceptive and antipyretic effects of rhizome and stem extract of Schumannianthus dichotomus Roxb. in male and female mice

Schumannianthus dichotomus (Roxb.) is a perennial shrub from Marantaceace family. In traditional medicine, rhizome of the plant is used in fever and stem is used in earache. We aimed to substantiate these therapeutic claims by examining their effects in mice model. Antinociceptive effect was evaluated by three pain models and antipyretic effect was tested by yeast induced hyperthermia experiment. Influence of mice sexes on these pharmacological effects was examined by performing experiments separately on male and female mice. Quantitative analyses of total phenols and flavonoids were performed. Antinociceptive effects showed striking sex dimorphism. In hind paw licking test, male mice showed significant reductions in licking in both phases for both rhizome and stem extracts while significant effect was observed only in late phase in female mice. In writhing test, antinociception is more profound in male than in female. In hot plate test, stem was more effective than rhizome in male mice while female mice produced little effect for both extracts. Antipyretic experiment also showed varied effect in male and female mice; both extracts showed significant decrease in body temperatures. Rhizome showed greater effect in female mice while stem was more effective in male mice. Total phenol and flavonoid in rhizome were found 103.08 mg GAE (gallic acid equivalent) and 9.07mg QE (quercetin equivalent) respectively while in stem, these were 43.39mg GAE and 20.93 QE. Antinociceptive and antipyretic effects of rhizome and stem extracts endorsed the traditional uses of S. dichotomus. Also, differential effects based on mouse sex indicate the prerequisite of both male and female mice model in therapeutic evaluations of plant extract.

The GluA1 AMPAR subunit is necessary for hedonic responding but not hedonic value in female mice

The GluA1 subunit of the AMPA receptor has been implicated in anhedonia. Mice that lack GluA1 (Gria1 knockout mice) show reduced lick cluster size, a measure of palatability in feeding behaviour. This deficit may reflect a role for GluA1 in encoding the hedonic value of palatable substances or instead a role for GluA1 in the behavioural expression of hedonic value. We tested the role of GluA1 in hedonic value by assessing sensitivity to changes in the rewarding property of sucrose as a consequence of negative/positive contrast effects in female mice. During training, on half of the days consumption of a flavour (CS+) mixed with 4% sucrose was preceded by consumption of 1% sucrose (positive contrast). On the other half of days consumption of a different flavour (CS–) mixed with 4% sucrose was preceded by consumption of 16% sucrose (negative contrast). In the test session both wild-type, controls and Gria1 knockout mice consumed more of the CS+ flavour than the CS– flavour. While Gria1 knockout mice showed reduced lick cluster sizes, both genotypes made larger lick clusters for the CS+ flavour than the CS– flavour suggesting that the CS+ was more palatable than the CS–. A follow up experiment in normal mice demonstrated that the negative contrast procedure resulted in a conditioned reduction of palatability of the CS– in comparison to an associatively neutral, novel flavour. The results failed to demonstrate a role for GluA1 in hedonic value suggesting that, instead, GluA1 is necessary for hedonic responding.

Preventative Effect of Mebendazole against Malignancies in Neurofibromatosis 1.

Patients with RASopathy Neurofibromatosis 1 (NF1) are at a markedly increased risk of the development of benign and malignant tumors. Malignant tumors are often recalcitrant to treatments and associated with poor survival; however, no chemopreventative strategies currently exist. We thus evaluated the effect of mebendazole, alone or in combination with cyclooxygenase-2 (COX-2) inhibitors, on the prevention of NF1-related malignancies in a cis Nf1+/−;Tp53+/− (NPcis) mouse model of NF1. Our in vitro findings showed that mebendazole (MBZ) inhibits the growth of NF1-related malignant peripheral nerve sheath tumors (MPNSTs) through a reduction in activated guanosine triphosphate (GTP)-bound Ras. The daily MBZ treatment of NPcis mice dosed at 195 mg/kg daily, initiated 60 days after birth, substantially delayed the formation of solid malignancies and increased median survival (p < 0.0001). Compared to placebo-treated mice, phosphorylated extracellular signal-regulated kinase (pERK) levels were decreased in the malignancies of MBZ-treated mice. The combination of MBZ with COX-2 inhibitor celecoxib (CXB) further enhanced the chemopreventative effect in female mice beyond each drug alone. These findings demonstrate the feasibility of a prevention strategy for malignancy development in high-risk NF1 individuals.

Antidepressant-like effect of a selenopropargylic benzamide in mice: involvement of the serotonergic system.

Major depressive disorder is a psychiatric disorder that requires considerable attention, since it dramatically impairs the quality of life of the sufferers. The available treatments do not have the efficacy needed, often presenting several side effects. Organoselenium compounds and benzamides have presented some pharmacological properties, among them an antidepressant-like effect. This study evaluated the antidepressant-like effect of N-(3-(phenylselanyl)prop-2-yn-1-yl)benzamide (SePB), an organoselenium compound containing a benzamide moiety, on the forced swimming test (FST) and the tail suspension test (TST) in mice, as well as the involvement of the serotonergic system in its effect. SePB, tested after different times (15-120min) and doses (1-50mg/kg, intragastrically (i.g.)), reduced immobility of male mice during FST and TST, without changing locomotor activity in the open-field test (OFT), demonstrating its antidepressant-like effect. SePB (10mg/kg) also produced an antidepressant-like effect in female mice in the TST. The preadministration of the serotonin (5-HT) depletor p-chlorophenylalanine (pCPA; 100mg/kg, intraperitoneal route (i.p.) once daily for 4days) prevented the anti-immobility effect of SePB, indicating that the serotonergic system is involved in the SePB antidepressant-like effect. The preadministration of the selective serotonergic receptor antagonists WAY100635 (0.1mg/kg, subcutaneous route (s.c.), a selective 5-HT1A receptor antagonist), ketanserin (1mg/kg, i.p., a 5-HT2A/2C receptor antagonist), and ondansetron (1mg/kg, i.p., a selective 5-HT3 receptor antagonist) also prevented the anti-immobility effect of SePB, demonstrating that these receptors are involved in the antidepressant-like effect of SePB. The search for new antidepressants drugs is a noteworthy goal. This study has described a new compound with an antidepressant-like effect, whose mechanism of action is related to modulation of the serotonergic system.

Yellow-colored extract from cashew byproduct – Nonclinical safety assessment

Natural and synthetic dyes are widely used in foodstuff, medicines and cosmetics industries to enhance and/or restore the color of the final products. This study aimed to evaluate the safety of oral consumption of one carotenoids and anacardic acids-enriched extract (CAE), obtained by green extraction from cashew apple residue fibers, a byproduct of the cashew juice industry. Presenting intense yellow color, CAE could be proposed as a new natural dye. Single and repeated-dose oral toxicity (30 days) were evaluated in female Swiss mice at doses ranging from 50 to 1000 mg/kg, while (anti)mutagenic effects were evaluated in CHO–K1 cells (in vitro Cytokinesis-Block Micronucleus assay - CBMN) and in erythrocytes collected from murine bone marrow (in vivo). CAE did not induce toxic or mutagenic effects in female mice even after 30 days of treatment, regardless of the dose used. Considering cyclophosphamide (CPA)-challenged animals treated with CAE, neither antimutagenic effect was observed nor CAE increased CPA-mutagenic effects although in vitro CBMN results indicated that CAE might increase methyl methanesulfonate-induced micronuclei (MN) frequency besides promoting reduction on CPA-induced MN frequency. The obtained results suggest that CAE may be a safe source of carotenoids with potential use as industrial dye.

Neuropeptide-S-receptor deficiency affects sex-specific modulation of safety learning by pre-exposure to electric stimuli.

Neuropeptide S (NPS) is a neuropeptide involved in the regulation of fear. Because safety learning is impaired in patients suffering from anxiety-related psychiatric disorders, and polymorphisms of the human neuropeptide S receptor (NPSR) gene have also been associated with anxiety disorders, we wanted to investigate whether NPSR-deficiency interferes with safety learning, and how prior stress would affect this type of learning. We first investigated the effect of pre-exposure to two different types of stressors (electric stimuli or immobilization) on safety learning in female and male C57Bl/6 mice, and found that while stress induced by electric stimuli enhanced safety learning in males, there were no differences in safety learning following immobilization stress. To further investigate the role of the NPS system in stress-induced modulation of safety learning, we exposed NPSR-deficient mice to stress induced by electric stimuli 10 days before safety learning. In nonstressed male mice, NPSR-deficiency enhanced safety learning. As in male C57Bl/6 mice, pre-exposure to electric stimuli increased safety learning in male NPSR +/+ mice. This pre-exposure effect was blocked in NPSR-deficient male mice showing impaired, but still intact, safety learning in comparison to their NPSR +/+ and NPSR +/- littermates. There was neither a pre-exposure nor a genotype effect in female mice. Our findings provide evidence that pre-exposure to stress induced by electric stimuli enhances safety learning in male mice, and that NPSR-deficiency prevents the beneficial effect of stress exposure on safety learning. We propose an inverted U-shape relationship between stress and safety learning.

The Incretin Effect in Female Mice With Double Deletion of GLP-1 and GIP Receptors.

To establish the contribution of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) for the incretin effect after oral glucose, studies were undertaken in female mice with genetic deletion of receptors for GIP and GLP-1 (double incretin receptor knockout [DIRKO] mice) and their wild-type (WT) counterparts. Insulin secretion was explored after oral glucose (doses ranging from 0 to 100 mg), after intravenous glucose (doses ranging from 0 to 0.75 g/kg), and after oral and intravenous glucose at matching circulating glucose. DIRKO mice had glucose intolerance after oral glucose challenges in association with impaired beta-cell function. Suprabasal area under the curve for C-peptide (AUCC-peptide) correlated linearly with suprabasal AUCglucose both in WT (r = 0.942, P = .017) and DIRKO mice (r = 0.972, P = .006). The slope of this regression was lower in DIRKO than in WT mice (0.012 ± 0.006 vs 0.031 ± 0.006 nmol C-peptide/mmol glucose, P = .042). In contrast, there was no difference in the insulin response to intravenous glucose between WT and DIRKO mice. Furthermore, oral and intravenous glucose administration at matching glucose levels showed that the augmentation of insulin secretion after oral glucose (the incretin effect) in WT mice (11.8 ± 2.3 nmol/L min) was entirely absent in DIRKO mice (3.3 ± 1.2 nmol/L min). We conclude that GIP and GLP-1 are required for normal glucose tolerance and beta-cell function after oral glucose in mice, that they are the sole incretin hormones after oral glucose at higher dose levels, and that they contribute by 65% to insulin secretion after oral glucose.