Gamma-aminobutyric Acid Receptor Research Articles

Design, Synthesis, and Biological Evaluation of Novel Spiro Imidazobenzodiazepines to Identify Improved Inhaled Bronchodilators.

Novel gamma-aminobutyric acid receptor (GABAAR) ligands structurally related to imidazobenzodiazepine MIDD0301 were synthesized using spiro-amino acid N-carboxyanhydrides (NCAs). These compounds demonstrated increased resistance to phase 2 metabolism and avoided the formation of a 6H isomer. Compound design was guided by molecular docking using the available crystal structure of the α1β3γ2 GABAAR and correlated with in vitro binding data. The carboxylic acid containing GABAAR ligands have high aqueous solubility, low permeability, and low cell toxicity. The inability of GABAAR ligands to cross the blood-brain barrier was confirmed in vivo by the absence of sensorimotor inhibition. Pharmacological activities at lung GABAARs were demonstrated by ex vivo relaxation of guinea pig airway smooth muscle and reduction of methacholine-induced airway hyperresponsiveness (AHR) in conscious mice. We identified bronchodilator 5c with an affinity of 9 nM for GABAARs that was metabolically stable in the presence of human and mouse microsomes.

Protective Effect of Baclofen on Ovarian Cystogenesis and Morphine-Induced Lipid Profile Change in Female Rats.

Morphine induces ovarian cysts that cause obesity and disrupt sex hormone secretion. Baclofen, a gamma-aminobutyric acid receptor agonist, can help regulate sex hormones and reduce harmful blood lipids by protecting against morphine-induced gamma-aminobutyric acid inhibition. We investigated the prophylactic effect of baclofen in rats receiving morphine by comparing with the untreated groups. Forty eight female Wistar rats were randomly divided into several groups, including control (saline 1 mL/kg, i.p.), morphine (5 mg/kg, i.p.), baclofen (10, 20, and 30 mg/kg, i.p.), and baclofen (10, 20, and 30 mg/kg) before morphine (5 mg/kg). Twenty four hours after the treatment, blood and serum samples were taken to check the levels of gonadotropins (LH & FSH) and lipid profile. The ovaries and uterus were also studied, and a proinflammatory nitric oxide (NO) diagnostic test was completed. The results were analyzed using analysis of variance (α = 0.05). In comparison with the control group, the levels of LH and not FSH decreased in the morphine group and the number of ovarian cysts was more in the morphine group. These problems were not observed in the group of baclofen alone and baclofen + morphine. However, the triglyceride level increased slightly in the baclofen 30 mg/kg + morphine group. But the LDL level somewhat decreased. The proinflammatory NO system did not show significant activation in the ovary and uterus, except for the baclofen 10 mg/kg + baclofen group. Morphine can cause ovarian cysts by lowering LH but baclofen prophylaxis can protect reproductive properties by adapting major metabolic changes.

A Human Microglial Cell Line Expresses γ-Aminobutyric Acid (GABA) Receptors and Responds to GABA and Muscimol by Increasing Production of IL-8

Gamma-aminobutyric acid (GABA) is an essential neurotransmitter and an important regulator of neuroinflammation and disease. Microglia are important immune cells in the brain that express GABA receptors (GABAR) and respond to both GABA and GABAR agonists, yet the effect of GABA on microglial inflammatory responses is unclear. We hypothesized that GABA and GABAR agonists might modify the activation of a human microglial cell line (HMC3). We further hypothesized that Amanita muscaria extract (AME-1), which contained GABAR agonists (GABA and muscimol), would similarly stimulate HMC3. Ligand-gated GABAR (GABAAR) and G protein-coupled GABAR (GABABR) subunit expression was analyzed by qRT-PCR, metabolic activity was determined by nicotinamide adenine dinucleotide (NADH)-dependent oxidoreductase assay (XTT), reactive oxygen species (ROS) generation was analyzed by 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA), and interleukin-8 (IL-8) production was analyzed by an enzyme-linked immunosorbent assay (ELISA). HMC3 expressed several neuroreceptors such as subunits of the GABAA receptor (GABAAR). HMC3 constitutively produce IL-8 and ROS. Both muscimol and GABA stimulated HMC3 to produce more IL-8 but had no effect on constitutive ROS production. GABA and muscimol altered the morphology and Iba1 localization of HMC3. GABA, but not muscimol, increased HMC3 metabolic activity. Similarly, AME-1 induced HMC3 to produce more IL-8 but not ROS and altered cell morphology and Iba1 localization. GABA induction of IL-8 was blocked by bicuculline, an antagonist of GABAAR. AME-1-induced production of IL-8 was not blocked by bicuculline, suggesting that AME-1’s effect on HMC3 was independent of GABAAR. In conclusion, these data show that GABA and GABA agonists stimulate HMC3 to increase their production of IL-8. Mixtures that contain GABA and muscimol, such as AME-1, have similar effects on HMC3 that are independent of GABAAR.

Narrative Review of Topiramate: Clinical Uses and Pharmacological Considerations.

Due to the diverse mechanisms of action of antiseizure drugs, there has been a rise in prescriptions of these drugs for non-epileptic pathologies. One drug that is now being used for a variety of conditions is topiramate. This is a narrative review that used PubMed, Google Scholar, MEDLINE, and ScienceDirect to review literature on the clinical and pharmacologic properties of topiramate. Topiramate is a commonly prescribed second-generation antiseizure drug. The drug works through multiple pathways to prevent seizures. In this regard, topiramate blocks sodium and calcium voltage-gated channels, inhibits glutamate receptors, enhances gamma-aminobutyric acid (GABA) receptors, and inhibits carbonic anhydrase. Topiramate is approved by the Food and Drug Administration (FDA) for epilepsy treatment and migraine prophylaxis. Topiramate in combination with phentermine is also FDA-approved for weight loss in patients with a body mass index (BMI) > 30. The current target dosing for topiramate monotherapy is 400mg/day and 100mg/day to treat epilepsy and migraines, respectively. Commonly reported side effects include paresthesia, confusion, fatigue, dizziness, and change in taste. More uncommon and serious adverse effects can include acute glaucoma, metabolic acidosis, nephrolithiasis, hepatotoxicity, and teratogenicity. Related to a broad side effect profile, physicians prescribing this drug should routinely monitor for side effects and/or toxicity. The present investigation reviews various anti-seizure medications before summarizing indications of topiramate, off-label uses, pharmacodynamics, pharmacokinetics, adverse effects, and drug-drug interactions.

Increased Excitability of Layer 2 Cortical Pyramidal Neurons in the Supplementary Motor Cortex Underlies High Cocaine-Seeking Behaviors

BackgroundMost efforts in addiction research have focused on the involvement of the medial prefrontal cortex, including the infralimbic, prelimbic, and anterior cingulate cortical areas, in cocaine-seeking behaviors. However, no effective prevention or treatment for drug relapse is available. MethodsWe focused instead on the motor cortex, including both the primary and supplementary motor areas (M1 and M2, respectively). Addiction risk was evaluated by testing cocaine seeking after intravenous self-administration (IVSA) of cocaine in Sprague Dawley rats. The causal relationship between the excitability of cortical pyramidal neurons (CPNs) in M1/M2 and addiction risk was explored by ex vivo whole-cell patch clamp recordings and in vivo pharmacological or chemogenetic manipulation. ResultsOur recordings showed that on withdrawal day 45 (WD45) after IVSA, cocaine, but not saline, increased the excitability of CPNs in the cortical superficial layers (primarily layer 2, denoted L2) but not in layer 5 (L5) in M2. Bilateral microinjection of the GABAA (gamma-aminobutyric acid A) receptor agonist muscimol to the M2 area attenuated cocaine seeking on WD45. More specifically, chemogenetic inhibition of CPN excitability in L2 of M2 (denoted M2-L2) by the DREADD (designer receptor exclusively activated by designer drugs) agonist compound 21 prevented drug seeking on WD45 after cocaine IVSA. This chemogenetic inhibition of M2-L2 CPNs had no effects on sucrose seeking. In addition, neither pharmacological nor chemogenetic inhibition manipulations altered general locomotor activity. ConclusionsOur results indicate that cocaine IVSA induces hyperexcitability in the motor cortex on WD45. Importantly, the increased excitability in M2, particularly in L2, could be a novel target for preventing drug relapse during withdrawal.

Baclofen as a Cause of Impaired Consciousness in a Haemodialysis Patient: A Case Report and Literature Review

Baclofen is an agonist of the gamma-aminobutyric acid (GABA) receptor found on both the pre-and postsynaptic neurones in the central and peripheral nervous systems [1]. Binding to GABAB receptors reduces the activation of the neuronal action potentials supplying muscle spindles, resulting in muscle relaxation [2]. This effect is used therapeutically to treat muscle spasticity in conditions such as multiple sclerosis [3]. In addition, the side effects of baclofen, including dizziness and drowsiness, are thought to result from the activation of GABA receptors located in the central and sympathetic nervous systems [2].

Recommendations for selection and adaptation of rating scales for clinical studies of rapid-acting antidepressants.

The novel mechanisms of action (MOA) derived from some recently introduced molecular targets have led to regulatory approvals for rapid acting antidepressants (RAADs) that can generate responses within hours or days, rather than weeks or months. These novel targets include the N-methyl-D-glutamate receptor antagonist ketamine, along with its enantiomers and various derivatives, and the allosteric modulators of gamma-aminobutyric acid (GABA) receptors. There has also been a strong resurgence in interest in psychedelic compounds that impact a range of receptor sites including D1, 5-HT7, KOR, 5-HT5A, Sigma-1, NMDA, and BDNF. The RAADs developed from these novel targets have enabled successful treatment for difficult to treat depressed individuals and has generated a new wave of innovation in research and treatment. Despite the advances in the neurobiology and clinical treatment of mood disorders, we are still using rating instruments that were created decades ago for drugs from a different era (e.g., The Hamilton and Montgomery-Åsberg depression rating scales, HDRS, and MADRS) continue to be used. These rating instruments were designed to assess mood symptoms over a 7-day time frame. Consequently, the use of these rating instruments often requires modifications to address items that cannot be assessed in short time frames, such as the sleep and appetite items. This review describes the adaptative approaches that have been made with the existing scales to meet this need and examines additional domains such as daily activities, side effects, suicidal ideation and behavior, and role functioning. Recommendations for future studies are described, including the challenges related to implementation of these adapted measures and approaches to mitigation.

Promising Insecticidal Properties of Essential Oils from Artemisia aragonensis Lam. and Artemisia negrei L. (Asteraceae) by Targeting Gamma-Aminobutyric Acid and Ryanodine Receptor Proteins: In Vitro and In Silico Approaches

Artemisia negrei (A. negrei) and Artemisia aragonensis (A. aragonensis) are in the family Asteraceae, which has been used in traditional medicine. The use of plant-derived insecticides has become a promising strategy to reduce the harmful effects of synthetic insecticides and overcome the bio-resistance of pest insects to insecticides. In this regard, the purpose of the current study was to determine the chemical composition and evaluate insecticidal effects of essential oils (EOs) extracted from A. negrei (EON) and A. aragonensis (EOA). Notably, all chemical constituents present in the EOs were identified through GC-MS analysis, whilst the insecticidal properties against Callosobruchus maculatus Fab. (C. maculatus) were investigated by use of in vitro an in silico approaches. The obtained results showed that both tested EOs present a significant insecticidal effect against C. maculatus, which increased significantly upon the dose used in both contact and inhalation tests. The lethal concentrations (LC50) for the inhalation test were found to be 2.1 and 2.97 μL/L, while in the contact test they were 2.08 and 2.74 μL/L of air for EON and EOA, respectively. At 5 μL/L of air, the spawn reduction rate was 88.53 % and 77.41%, while the emergence reduction rate was 94.86% and 81.22% by EON and EOA, respectively. With increasing doses of up to 20 μL/L of air, the reduction in individual emergence reached 100% by the two oils tested after 36 h of treatment. In addition, Molecular docking (MD) simulations supported the in vitro findings and indicated that certain identified components in EOA and EON exhibited stronger hydrogen bonding interactions with the target receptors. Interestingly, the prediction of ADMET properties indicates that the molecules investigated have great pharmacokinetic profiles with no side effects. Taken together, our findings suggest that EOA and EON may exert both potential contact and inhalation insecticidal actions and could be used as an alternative tool for the control of this major insect pest of stored products.

BS3 Chemical Crosslinking Assay: Evaluating the Effect of Chronic Stress on Cell Surface GABAA Receptor Presentation in the Rodent Brain.

Anxiety is a state of emotion that variably affects animal behaviors, including cognitive functions. Behavioral signs of anxiety are observed across the animal kingdom and can be recognized as either adaptive or maladaptive responses to a wide range of stress modalities. Rodents provide a proven experimental model for translational studies addressing the integrative mechanisms of anxiety at the molecular, cellular, and circuit levels. In particular, the chronic psychosocial stress paradigm elicits maladaptive responses mimicking anxiety-/depressive-like behavioral phenotypes that are analogous between humans and rodents. While previous studies show significant effects of chronic stress on neurotransmitter contents in the brain, the effect of stress on neurotransmitter receptor levels is understudied. In this article, we present an experimental method to quantitate the neuronal surface levels of neurotransmitter receptors in mice under chronic stress, especially focusing on gamma-aminobutyric acid (GABA) receptors, which are implicated in the regulation of emotion and cognition. Using the membrane-impermeable irreversible chemical crosslinker, bissulfosuccinimidyl suberate (BS3), we show that chronic stress significantly downregulates the surface availability of GABAA receptors in the prefrontal cortex. The neuronal surface levels of GABAA receptors are the rate-limiting process for GABA neurotransmission and could, therefore, be used as a molecular marker or a proxy of the degree of anxiety-/depressive-like phenotypes in experimental animal models. This crosslinking approach is applicable to a variety of receptor systems for neurotransmitters or neuromodulators expressed in any brain region and is expected to contribute to a deeper understanding of the mechanisms underlying emotion and cognition.

Insights into the leveraging of GABAergic signaling in cancer therapy.

Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain of adult mammals. Several studies have demonstrated that the GABAergic system may regulate tumor development via GABA receptors, downstream cyclic adenosine monophosphate (cAMP) pathway, epithelial growth factor receptor (EGFR) pathway, AKT pathway, mitogen-activated protein kinase (MAPK) or extracellular signal-related kinases (ERK) pathway, and matrix metalloproteinase (MMP) pathway, although the exact mechanism is unclear. Pioneering studies reported that GABA signaling exists and functions in the cancer microenvironment and has an immunosuppressive effect that contributes to metastasis and colonization. This article reviews the molecular structures and biological functions of GABAergic components correlated with carcinogenesis, the mechanisms underlying GABAergic signaling that manipulate the proliferation and invasion of cancer cells, and the potential GABA receptor agonists and antagonists for cancer therapy. These molecules may provide an avenue for the development of specific pharmacological components to prevent the growth and metastasis of various cancers.

The effect of maternal diabetes on the expression of gamma-aminobutyric acid and metabotropic glutamate receptors in male newborn rats' inferior colliculi.

Few studies have examined the molecular alterations in the auditory pathway of infants of diabetic mothers, notwithstanding the fact that maternal diabetes may have an impact on the development of the neonatal peripheral and central nervous systems. Male newborn rats were studied to determine how maternal diabetes affected the expression of gamma-aminobutyric acid (GABAAα1 and GABAB1) and metabotropic glutamate (mGlu2) receptors in the inferior colliculus (IC) in this research. Female rats were given a single intraperitoneal injection of streptozotocin (STZ) at a 65 mg/kg dose to develop a model of diabetic mothers. The study population was split into sham, diabetes without treatment, and diabetes with insulin groups. Their male neonatal rats were anesthetized on P0, P7, and P14 after mating and delivery. The receptors' distribution pattern was studied using immunohistochemistry (IHC). Pairwise comparison in the groups revealed that the GABA receptors (Aα1 and B1) were significantly downregulated in the diabetes without treatment group (p<0.001). Furthermore, pairwise comparison in the groups indicated significant mGlu2 upregulation in the diabetes without treatment group (p<0.001). Regarding the concentration of all receptors, there was no discernible distinction between the diabetes with insulin and sham groups. This investigation showed that the concentration of GABAAα1 and GABAB1 receptors decreased significantly over time, whereas the concentration of mGlu2 receptors increased significantly over time in male neonatal rats born to streptozotocin-induced diabetic mothers.

Heukharang lettuce (Lactuca sativa L.) leaf extract displays sleep-promoting effects through GABAA receptor

Ethnopharmacological relevanceAlthough lettuce is traditionally known to have hypnotic and sedative effects, to date, only a few studies have documented its sleep-promoting effects and elucidated the related mechanisms. Aim of the studyWe aimed to investigate the sleep-promoting activity of Heukharang lettuce leaf extract (HLE) with increased lactucin content, known as a sleep-promoting substance in lettuce, in animal models. Materials and methodsTo evaluate the effect of HLE on sleep behavior, analysis of electroencephalogram (EEG), gene expression of brain receptors, and activation mechanisms using antagonists were investigated in rodent models. ResultsHigh-performance liquid chromatography analysis showed that HLE contained lactucin (0.78 mg/g of extract) and quercetin-3-glucuronide (1.3 mg/g of extract). In the pentobarbital-induced sleep model, the group administered 150 mg/kg of HLE showed a 47.3% increase in sleep duration time as compared to the normal group (NOR). The EEG analysis showed that the HLE significantly increased non-rapid eye movement (NREM), where delta waves were improved by 59.5% when compared to the NOR, resulting in increased sleep time. In the caffeine-induced arousal model, HLE significantly decreased the awake time increased by caffeine administration (35.5%) and showed a similar level to NOR. In addition, HLE increased the gene and protein expression of gamma-aminobutyric acid receptor type A (GABAA), GABA type B, and 5-hydroxytryptamine (serotonin) receptor 1A. In particular, in comparison to the NOR, the group administered 150 mg/kg HLE showed an increase in expression levels of GABAA and protein by 2.3 and 2.5 times, respectively. When the expression levels were checked using GABAA receptor antagonists, HLE showed similar levels to NOR, as the sleep duration was reduced by flumazenil (45.1%), a benzodiazepine antagonist. ConclusionsHLE increased NREM sleep and significantly improved sleep behavior due to its action on the GABAA receptors. The collective findings suggest that HLE can be used as a novel sleep-enhancing agent in the pharmaceutical and food industries.

Glutamate and GABA receptors in non-neural animals (Placozoa): Preadaptation to neural transmission

Origins of neural system is one of the major transitions in planetary evolution. Many details of these transitions are still unknown. In particular, high diversity of neurotransmitters lacks convincing explanation so far. We analyze homologues of neuronal glutamate and gamma-aminobutyric acid (GABA) receptors of Placozoa – animal phyla lacking neurons but displaying motility and complex behaviour. Phylogenetic analysis and comparison of amino acids in ligand-binding pockets show that glutamate and GABA-like receptors of Placozoa are surprisingly numerous, diverse and fast-evolving. All these traits are characteristic of odorant rather than neurotransmitter receptors of higher animals. We argue that chemoreception system was an important source of diverse receptors for emerging nervous system to recruit, and that amino acid neurotransmitters (glutamate, GABA, glycine) were relevant external stimuli for early animals before the emergence of nervous system.

Low-frequency Electrical Stimulation of the Hippocampus Plays a Role in the Treatment of Pharmacoresistant Epilepsy by Blocking the PKA-CREB Pathway.

The objective of this study is to study the mechanism of Low frequency electrical stimulation (LFS) in the treatment of drug-resistant epilepsy by regulating the protein kinase A (PKA)-cAMP response element-binding protein (CREB) signaling pathway upstream of gamma aminobutyric acid A (GABAA) receptor. Primary hippocampal neurons were extracted and cultured from fetal rat brains and randomly divided into the normal control group, PKA-CREB agonist group, and PKA-CREB inhibitor group. Drug-resistant epileptic rats were established and randomly divided into the pharmacoresistant group, LFS group, PKA-CREB agonist combined with hippocampal LFS group, and PKA-CREB inhibitor combined with hippocampal LFS group. The normal rats were in the normal control group and drug-sensitive rats were in the pharmacosensitive group. The seizure frequency of epileptic rats was determined using video surveillance. The expression of PKA, CREB, p-CREB, and GABAA receptor subunits α1 and β2 of each group were detected using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting assays. The in vitro expression levels of PKA, CREB, and p-CREB in the agonist group were significantly higher than those in the normal control group (NRC group), while the expression levels of GABAA receptor subunits α1 and β2 were significantly lower than those in the NRC group. The expression levels of PKA, CREB, and p-CREB in the inhibitor group were significantly lower, while the expression levels of GABAA receptor subunits α1 and β2 were significantly higher than those in the NRC group. The in vivo seizure frequency was significantly lower in the LFS group than in the pharmacoresistant group (PRE group). Compared to the LFS group, the seizure frequency and the expression levels of PKA, CREB, and p-CREB in the rat hippocampus were significantly higher, and the expression levels of GABAA receptor subunits α1 and β2 were significantly lower in the agonist group. The results in the inhibitor group were exactly the opposite of those in the agonist group. The PKA-CREB signaling pathway is involved in the regulation of GABAA receptor subunits α1 and β2. In addition, LFS plays an important role in increasing GABAA receptor expression by regulating the PKA-CREB signaling pathway.

The effect of acute topiramate administration on morphine withdrawal syndrome and brain-derived neurotrophic factor in central nervous system

ABSTRACT Objectives Nucleus accumbens plays an important role in opioid addiction. Topiramate, increases postsynaptic gamma-aminobutyric acid receptor activity and antagonizes glutamatergic activity. Brain-derived neurotrophic factor (BDNF), which plays a key role in synaptic plasticity, is produced from proBDNF. The aim of this study is to investigate the effects of 100 µM topiramate applied into the lateral ventricle or nucleus accumbens on naloxone-induced morphine withdrawal and the BDNF/proBDNF ratio in the frontal cortex. Methods In the study, 36 adult male Wistar rats weighing 250–350 g were used. Morphine dependence was created with morphine pellets following guide cannula implantations. Withdrawal findings were evaluated in naloxone-induced morphine withdrawal syndrome following topiramate administration, and locomotor activity measurements were performed simultaneously. The brains of sacrificed animals were removed for determination of BDNF/proBDNF ratio. Results Topiramate administered by either route significantly suppressed the number of jumps in morphine withdrawal. Topiramate applied into the nucleus accumbens significantly reduced stereotypical behavior in morphine withdrawal, but did not cause any changes in other locomotor activity behaviors. Topiramate applied into the lateral ventricle significantly decreased the BDNF/proBDNF ratio, whereas administered into the nucleus accumbens significantly increased this ratio. Conclusion The findings of this study indicate that topiramate administered into the lateral ventricle and nucleus accumbens reduces naloxone-induced morphine withdrawal symptoms, stereotypical locomotor activity, and changes the BDNF/proBDNF ratio.

Profiling GABA(A) Receptor Subunit Expression in the Hippocampus of PMDD Rat Models Based on TCM Theories.

γ-Aminobutyric acid type A receptors (GABAARs) play an important role in cognitive and emotional regulation and are related to the hippocampus. However, little is known regarding patterns of hippocampal GABAAR subunit expression in rat models of premenstrual dysphoric disorder (PMDD). This study investigated the above changes by establishing two PMDD rat models based on Traditional Chinese Medicine (TCM) theories, namely, PMDD liver-qi invasion syndrome (PMDD-LIS) and PMDD liver-qi depression syndrome (PMDD-LDS). Behavioral tests were used to detect depression and irritability emotion. Western blot analysis was used to investigate protein levels of GABAAR α1, α2, α4, α5, β2, β3, and δ subunits, whereas ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis was performed to determine gamma-aminobutyric acid (GABA) and glutamate (Glu) levels in the hippocampus across each group. Concurrently, behavioral data indicated that the PMDD-LDS and PMDD-LIS rat models had been successfully established. GABAAR α2, α5, β2, and δ subunit was significantly upregulated, whereas α4 was significantly downregulated (P < 0.05) in PMDD-LDS rat models relative to controls. On the other hand, GABAAR α1, α2, and β3 were significantly downregulated while α4 and β2 were significantly upregulated in PMDD-LIS rat models relative to the control group (P < 0.05). Moreover, GABA levels significantly decreased, while Glu and the ratio of glutamate to GABA increased in PMDD-LIS rat models (P < 0.05). Conversely, GABA and Glu levels significantly decreased, whereas the ratio of glutamate to GABA increased in PMDD-LIS rat models (P < 0.05). Conclusively, our results revealed differential expression of GABAAR α1, α2, α4, α5, β2, β3, and δ subunits between PMDD-LIS and PMDD-LDS rat models, suggesting that they may be biomarkers in the pathogenesis of PMDD.

Neurobehavioral sex-related differences in Nf1+/− mice: female show a “camouflaging”-type behavior

BackgroundNeurofibromatosis type 1 (NF1) is an inherited neurocutaneous disorder associated with neurodevelopmental disorders including autism spectrum disorder (ASD). This condition has been associated with an increase of gamma-aminobutyric acid (GABA) neurotransmission and, consequently, an excitation/inhibition imbalance associated with autistic-like behavior in both human and animal models. Here, we explored the influence of biological sex in the GABAergic system and behavioral alterations induced by the Nf1+/− mutation in a murine model.MethodsJuvenile male and female Nf1+/− mice and their wild-type (WT) littermates were used. Hippocampus size was assessed by conventional toluidine blue staining and structural magnetic resonance imaging (MRI). Hippocampal GABA and glutamate levels were determined by magnetic resonance spectroscopy (MRS), which was complemented by western blot for the GABA(A) receptor. Behavioral evaluation of on anxiety, memory, social communication, and repetitive behavior was performed.ResultsWe found that juvenile female Nf1+/− mice exhibited increased hippocampal GABA levels. Moreover, mutant female displays a more prominent anxious-like behavior together with better memory performance and social behavior. On the other hand, juvenile Nf1+/− male mice showed increased hippocampal volume and thickness, with a decrease in GABA(A) receptor levels. We observed that mutant males had higher tendency for repetitive behavior.ConclusionsOur results suggested a sexually dimorphic impact of Nf1+/− mutation in hippocampal neurochemistry, and autistic-like behaviors. For the first time, we identified a “camouflaging”-type behavior in females of an animal model of ASD, which masked their autistic traits. Accordingly, like observed in human disorder, in this animal model of ASD, females show larger anxiety levels but better executive functions and production of normative social patterns, together with an imbalance of inhibition/excitation ratio. Contrary, males have more externalizing disorders, such as hyperactivity and repetitive behaviors, with memory deficits. The ability of females to camouflage their autistic traits creates a phenotypic evaluation challenge that mimics the diagnosis difficulty observed in humans. Thus, we propose the study of the Nf1+/− mouse model to better understand the sexual dimorphisms of ASD phenotypes and to create better diagnostic tools.

Early central cardiovagal dysfunction after high fat diet in a murine model

High fat diet (HFD) promotes cardiovascular disease and blunted cardiac vagal regulation. Temporal onset of loss of cardiac vagal control and its underlying mechanism are presently unclear. We tested our hypothesis that reduced central vagal regulation occurs early after HFD and contributes to poor cardiac regulation using cardiovascular testing paired with pharmacology in mice, molecular biology, and a novel bi-transgenic mouse line. Results show HFD, compared to normal fat diet (NFD), significantly blunted cardio/pulmonary chemoreflex bradycardic responses after 15 days, extending as far as tested (> 30 days). HFD produced resting tachycardia by day 3, reflected significant loss of parasympathetic tone. No differences in bradycardic responses to graded electrical stimulation of the distal cut end of the cervical vagus indicated diet-induced differences in vagal activity were centrally mediated. In nucleus ambiguus (NA), surface expression of δ-subunit containing type A gamma-aminobutyric acid receptors (GABAA(δ)R) increased at day 15 of HFD. Novel mice lacking δ-subunit expression in vagal motor neurons (ChAT-δnull) failed to exhibit blunted reflex bradycardia or resting tachycardia after two weeks of HFD. Thus, reduced parasympathetic output contributes to early HFD-induced HR dysregulation, likely through increased GABAA(δ)Rs. Results underscore need for research on mechanisms of early onset increases in GABAA(δ)R expression and parasympathetic dysfunction after HFD.

Acid treated montmorillonite - efficient catalyst in Prins reaction of alpha-methylstyrene with paraldehyde

Acid treated montmorillonite was used as a catalyst in Prins reaction of α methylstyrene with paraldehyde giving 2,4,6-trimethyl-4-phenyl-1,3-dioxane (Vertacetal). The product of this reaction is a bioactive compound, which can interact with GABA (gamma-aminobutyric acid) receptors and has fragrant properties. Montmorillonite (used for this reaction as catalyst) was prepared by treatment with hydrochloric, nitric, sulfuric or chloroacetic acid. The influence of acid used for treatment, and other reaction conditions (reaction temperature, solvent, reactant molar ratio, catalyst amount) on the reaction course were tested. Acid treated montmorillonite proved to be a catalyst suitable for this reaction – a high yield of desired product was obtained (>94%) at room temperature using different solvents. Solvent choice showed to be crucial for the reaction – the best results were obtained using nitromethane or 1,4-dioxane. The catalyst can be reused one time after calcination at 300 °C.

Association of GABRG3, GABRB3, HTR2A gene variants with autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental and neurobehavioral disorder characterized by impaired social communication, repetitive and restricted patterns of behavior, activity, or interest, and altered emotional processing. Reported prevalence is 4 times higher in men and it has increased in recent years. Immunological, environmental, epigenetic, and genetic factors play a role in the pathophysiology of autism. Many neurochemical pathways and neuroanatomical events are effective in determining the disease. It is still unclear how the main symptoms of autism occur because of this complex and heterogeneous situation. In this study, we focused on gamma amino butyric acid (GABA) and serotonin, which are thought to contribute to the etiology of autism; it is aimed to elucidate the mechanism of the disease by investigating variant changes in the GABA receptor subunit genes GABRB3, GABRG3 and the HTR2A gene, which encodes one of the serotonin receptors.200 patients with ASD between the ages of 3–9 and 100 healthy volunteers were included in the study. Genomic DNA isolation was performed from peripheral blood samples taken from volunteers. Genotyping was performed using the RFLP method with PCR specific for specific variants. Data were analyzed with SPSS v25.0 program.According to the data obtained in our study; In terms of HTR2A (rs6313 T102C) genotypes, the homozygous C genotype carrying frequency in the patient group and the homozygous T genotype carrying frequency in the GABRG3 (rs140679 C/T) genotypes were found to be significantly higher in the patient group compared to the control group (*p: 0.0001, p: 0.0001). It was determined that the frequency of individuals with homozygous genotype was significantly higher in the patient group compared to the control group and having homozygous genotypes increased the disease risk approximately 1.8 times. In terms of GABRB3 (rs2081648 T/C) genotypes, it was determined that there was no statistically significant difference in the frequency of carrying homozygous C genotype in the patient group compared to the control group (p: 0.36).According to the results of our study, we think that the HTR2A (rs6313 T102C) polymorphism is effective in modulating the empathic and autistic characteristics of individuals, and that the HTR2A (rs6313 T102C) polymorphism is more distributed in the post-synaptic membranes in individuals with a higher number of C alleles. We believe that this situation can be attributed to the spontaneous stimulatory distribution of the HTR2A gene in the postsynaptic membranes because of T102C transformation.In genetically based autism cases, carrying the point mutation in the rs6313 variant of the HTR2A gene and the C allele and the point mutation in the rs140679 variant of the GABRG3 gene and accordingly carrying the T allele provide a predisposition to the disease.