Nitric oxide role in anxiety-like behavior, memory and cognitive impairments in animal model of chronic migraine

Transmission of behavioral and cognitive impairments across generations in rats subjected to prenatal valproic acid exposure

BACKGROUND

Autism spectrum disorder (ASD) represents an inheritable neurodevelopmental condition characterized by social communication deficits and repetitive behaviors. Numerous studies have underscored the significant roles played by genetic and environmental factors in the etiology of ASD, and these factors are known to perpetuate behavioral impairments across generations.

OBJECTIVES

The primary objective of this study was to assess the behavioral and cognitive attributes in the second filial (F2) generation of male and female rats, with a particular focus on those whose parents had been exposed to valproic acid (VPA) during embryonic development.

METHODS

In this study, a cohort of 32 male and 32 female rats from the second filial (F2) generation, referred to as Mother.ASD, Father.ASD, or Both.ASD, was examined. These designations indicate whether the mother, father, or both parents had experienced embryonic exposure to valproic acid (600 mg/kg, i.p.). During adolescence, the F2 pups underwent behavioral and cognitive assessments, including open field testing, marble burying, social interaction evaluations, and Morris water maze tasks.

RESULTS

Our data revealed that while both the Mother.ASD and Father.ASD groups, regardless of sex, exhibited elevated anxiety-like behavior in the open field test. Only the Mother.ASD group displayed repetitive behaviors and deficits in social memory. Additionally, spatial memory impairments were observed in both sexes. These findings highlight the transmission of autistic-like behaviors in the offspring of Mother.ASD rats from both sexes. Nevertheless, future research endeavors should be more targeted in identifying the specific genes responsible for this transmission.

CONCLUSION

In summary, our findings underscore the transmission of autistic-like behaviors, including anxiety-like behavior, repetitive actions, impairments in social interactions, and deficits in memory, to the offspring of the Mother.ASD group, irrespective of their sex.

Electroacupuncture Inhibits Pain Memory and Related Anxiety-Like Behaviors by Blockading the GABAB Receptor Function in the Midcingulate Cortex

Pain memory is commonly considered an underlying cause of chronic pain and is also responsible for a range of anxiety. Electroacupuncture (EA) has been shown to ameliorate pain memories and exert anti-anxiety effects. Previous research has indicated that GABAergic neurons and/or GABA receptors (GABARs) in the midcingulate cortex (MCC) have potential associations with chronic pain and anxiety. However, there is no known empirical research that has specifically studied the effects of EA on the GABAergic system in the MCC. Here, we used cross-injection of carrageenan to establish the pain memory rats model. Immunofluorescence were used to detect the excitability of GABAergic neurons within MCC. Von Frey filament, elevated zero maze, and open field tests were used to measure mechanical allodynia and anxiety-like behaviors, combined with chemogenetic and pharmacologic technologies. Finally, this study provides evidence that pain memories contribute to generalized negative emotions and that downregulating the activity of GABAergic neurons within MCC could block pain memories and reverse anxiety emotion. Specifically, GABABR is involved in pain memory and related anxiety-like behaviors. Activation of GABAergic neurons in the MCC did not reverse the effects of EA on pain memories and related anxiety-like behaviors, whereas these effects could be reversed by a GABABR agonist. These findings highlight the functional significance of GABABR in the EA-mediated attenuation of pain memories and related anxiety-like behaviors in rats.

Design and Development of a Topical Nanogel Formulation Comprising of a Unani Medicinal Agent for the Management of Pain

The oil of the Unani medicinal herb Baboona (Matricaria chamomilla) has shown potential in the management of pain. However, predicaments such as poor skin penetration, skin sensitization, liable to degradation, and volatile nature restrict its use. Therefore, our group for the first time has developed a carrier-based delivery system to facilitate the direct application of chamomile oil to the forehead. The developed nanogel was characterized for physical parameters such as compatibility, TEM, and stability studies. Further, it was also evaluated for pH, viscosity, spread ability, and extrudability, as well as through texture analyses, in vitro studies, and skin irritation tests. The formulation was successfully developed with all the necessary attributes. The in vitro studies revealed the enhanced skin penetration of chamomile oil nanogel. The in vivo studies were also performed in chemically induced pain models, mimicking migraine. The studies show significant improvement of the pain threshold for chamomile nanogel when compared to the positive control group and the results were comparable to marketed diclofenac formulations. Finally, the encapsulation into nanogel reduced the skin irritation property. The nanogel formulation showed promising effects in the pain management of migraine.

Abscisic acid ameliorates motor disabilities in 6-OHDA-induced mice model of Parkinson's disease

Parkinson's disease (PD) is characterized by a myriad of symptoms, encompassing both motor disabilities and cognitive impairments. Recent research has shown that abscisic acid (ABA) is a phytohormone found in various brain regions of several mammals and exhibits neuroprotective properties. To investigate the effects of ABA on cognitive and motor disorders, a mouse model of PD was utilized. The administration of 6-hydroxydopamine (6-OHDA) to the lateral ventricles was conducted, with ABA (10 and 15 μg/mouse, i. c.v.) being administered for one week after the 6-OHDA injection for 4 days. Motor and cognitive performance were evaluated through the use of open field, rotarod, wire grip, and shuttle box tests. The results indicated that cognitive function and motor disorders were significantly impaired in 6-OHDA-treated animals. However, in mice treated with 6-OHDA, ABA (15 μg/mouse) significantly reversed balance and muscle strength deficits. It should be noted that the administration of ABA did not significantly improve cognitive impairment or rearing in Parkinsonism mice. Therefore, the findings suggest that ABA plays a crucial role in protecting mice from motor disabilities caused by 6-OHDA.

Amelioration of cognition impairments in the valproic acid-induced animal model of autism by ciproxifan, a histamine H3-receptor antagonist

Autism spectrum disorder is a neurodevelopmental disorder characterized by deficits in social communication and repetitive behavior. Many studies show that the number of cognitive impairmentscan be reduced by antagonists of the histamine H3 receptor (H3R). In this study, the effects of ciproxifan (CPX) (1 and 3 mg/kg, intraperitoneally) on cognitive impairments in rat pups exposed to valproic acid (VPA) (600 mg/kg, intraperitoneally) wereexamined on postnatal day 48-50 (PND 48-50) using marble-burying task (MBT), open field, novel object recognition (NOR), and Passive avoidance tasks. Famotidine (FAM) (10, 20, and 40 mg/kg, intraperitoneally) was also used to determine whether histaminergic neurotransmission exerts its procognitive effects via H2 receptors (H2Rs). Furthermore, a histological investigation was conducted to assess the degree of degeneration of hippocampal neurons. The results revealed that repetitive behaviors increased in VPA-exposed rat offspring in the MBT. In addition, VPA-exposed rat offspring exhibited more anxiety-like behaviors in the open field than saline-treated rats. It was found that VPA-exposed rat offspring showed memory deficits in NOR and Passive avoidance tasks. Our results indicated that 3 mg/kg CPX improved cognitive impairments induced by VPA, while 20 mg/kg FAM attenuated them. We concluded that 3 mg/kg CPX improved VPA-induced cognitive impairments through H3Rs. The histological assessment showed that the number of CA1 neurons decreased in the VPA-exposed rat offspring compared to the saline-exposed rat offspring, but this decrease was not significant. The histological assessment also revealed no significant differences in CA1 neurons in VPA-exposed rat offspring compared to saline-exposed rat offspring. However, CPX3 increased the number of CA1 neurons in the VPA + CPX3 group compared to the VPA + Saline group, but this increase was not significant. This study showed that rats prenatally exposed to VPA exhibit cognitive impairments in the MBT, open field, NOR, and Passive avoidance tests, which are ameliorated by CPX treatment on PND 48-50. In addition, morphological investigations showed that VPA treatment did not lead to neuronal degeneration in the CA1 subfield of the hippocampus in rat pups.

Hangover headache and its behavioral changes in rats

Objectives

The present study aims to establish and evaluate a rat model for hangover headaches caused by alcoholic drinks.

Materials and Methods

Chronic migraine (CM) model rats were divided into 3 groups, and intragastrically administered alcoholic drinks (sample A, B, or C) to simulate hangover headache attacks. The withdrawal threshold for the hind paw/face and the thermal latency of hind paw withdrawal were detected after 24 hr. Serum was collected from the periorbital venous plexus of rats in each group, and enzymatic immunoassays were used to determine the serum levels of calcitonin gene-related peptide (CGRP), substance P (SP), and nitric oxide (NO).

Results

Compared with the control group, the mechanical hind paw pain threshold was significantly lower in rats administered Samples A and B after 24 hr; however, no significant difference was observed across groups for the thermal pain threshold. The mechanical threshold for periorbital pain was only significantly reduced in rats administered Sample A. Immunoassays further indicated that serum levels of SP in the group administered Sample A were significantly higher than those in the control group; the serum levels of NO and CGRP were significantly higher in the group of rats receiving Sample B.

Conclusion

We successfully developed an effective and safe rat model for investigating alcohol drink induced hangover headaches. This model could be used to investigate the mechanisms associated with hangover headaches for the development of novel and promising candidates for the future treatment or prophylaxis of hangover headaches.

Dysregulation of Amino Acid, Lipid, and Acylpyruvate Metabolism in Idiopathic Intracranial Hypertension: A Non-targeted Case Control and Longitudinal Metabolomic Study

Background: Idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure occurring predominantly in women with obesity. The pathogenesis is not understood. We have applied untargeted metabolomic analysis using ultrahigh-performance liquid chromatography-mass spectrometry to characterize the cerebrospinal fluid (CSF) and serum in IIH compared to control subjects. Methods and findings: Samples were collected from IIH patients (n = 66) with active disease at baseline and again at 12 months following therapeutic weight loss. Control samples were collected from gender- and weight-matched healthy controls (n = 20). We identified annotated metabolites in CSF, formylpyruvate and maleylpyruvate/fumarylpyruvate, which were present at lower concentrations in IIH compared to control subjects and returned to values observed in controls following weight loss. These metabolites showed the opposite trend in serum at baseline. Multiple amino acid metabolic pathways and lipid classes were perturbed in serum and CSF in IIH alone. Serum lipid metabolite pathways were significantly increased in IIH. Conclusions: We observed a number of differential metabolic pathways related to amino acid, lipid, and acylpyruvate metabolism, in IIH compared to controls. These pathways were associated with clinical measures and normalized with disease remission. Perturbation of these metabolic pathways provides initial understanding of disease dysregulation in IIH.

The PPARα Regulation of the Gut Physiology in Regard to Interaction with Microbiota, Intestinal Immunity, Metabolism, and Permeability

Peroxisome proliferator-activated receptor alpha (PPARα) is expressed throughout the mammalian gut: in epithelial cells, in the villi of enterocytes and in Paneth cells of intestinal crypts, as well as in some immune cells (e.g., lamina propria macrophages, dendritic cells) of the mucosa. This review examines the reciprocal interaction between PPARα activation and intestinal microbiota. We refer to the published data confirming that microbiota products can influence PPARα signaling and, on the other hand, PPARα activation is able to affect microbiota profile, viability, and diversity. PPARα impact on the broad spectrum of events connected to metabolism, signaling (e.g., NO production), immunological tolerance to dietary antigens, immunity and permeability of the gut are also discussed. We believe that the phenomena described here play a prominent role in gut homeostasis. Therefore, in conclusion we propose future directions for research, including the application of synthetic activators and natural endogenous ligands of PPARα (i.e., endocannabinoids) as therapeutics for intestinal pathologies and systemic diseases assumed to be related to gut dysbiosis.

Prenatal ethanol exposure causes anxiety-like phenotype and alters synaptic nitric oxide and endocannabinoid signaling in dorsal raphe nucleus of adult male rats

Mood disorders, including anxiety and depression caused by prenatal ethanol exposure (PE) are prevalent conditions in fetal alcohol spectrum disorders (FASDs). Prenatal ethanol exposure is associated with persistent dysfunctions of several neurotransmitter systems, including the serotonin (5-HT) system, which plays a major role in mood regulation and stress homeostasis. While PE is known to disrupt the development of the 5-HT system, the cellular mechanisms by which it alters the function of dorsal raphe nucleus (DRn) 5-HT neurons and their synaptic inputs remain unknown. Here, we used a second-trimester binge-drinking pattern PE (two daily gavages of 15% w/v ethanol at 3 g/kg, 5-6 h apart) during gestational days 8 - 20 and measured anxiety-like behaviors of adult male rats using the elevated plus (EPM) and zero (ZM) mazes. We also employed ex-vivo electrophysiological and pharmacological approaches to unravel the mechanisms by which PE alters the excitability and synaptic transmission onto DRn 5-HT neurons. We found that PE enhanced anxiety-like behaviors in adult male rats and induced a persistent activation of DRn 5-HT neurons. The PE-induced activation of DRn 5-HT neurons was largely mediated by potentiation of DRn glutamate synapses, which was caused by activation of the nitrergic system and impaired endocannabinoid signaling. As such, the present study reveals "push-pull" effects of PE on nitrergic and eCB signaling, respectively, which mediate the enhanced activity of DRn 5-HT neurons and could contribute to anxiety-like behaviors observed in animal model of FASD.

Modelling migraine-related features in the nitroglycerin animal model: trigeminal hyperalgesia is associated with affective status and motor behavior

Migraine is a complex neurovascular disorder characterized by recurrent attacks of pain and other associated symptoms. Emotional-affective aspects are important components of pain, but so far they have been little explored in animal models of migraine. In this study, we aimed to explore the correlation between trigeminal hyperalgesia and affective status or behavioral components in a migraine-specific animal model. Male Sprague-Dawley rats were treated with nitroglycerin (10 mg/kg, i.p.) or its vehicle. Four hours later, anxiety, motor/exploratory behavior and grooming (a nociception index) were evaluated with the open field test. Rats were then exposed to formalin in the orofacial region to evaluate trigeminal hyperalgesia. The data analysis shows an inverse correlation between trigeminal hyperalgesia and motor or exploratory behavior, and a positive association with anxiety-like behavior or self-grooming. These findings further expand on the translational value of the migraine-specific model based on nitroglycerin administration and prompt additional parameters that can be investigated to explore migraine disease in its complexity.

Nitroglycerin as a model of migraine: Clinical and preclinical review

Migraine stands as one of the most disabling neurological conditions worldwide. It is a disorder of great challenge to study given its heterogeneous representation, cyclic nature, and complexity of neural networks involved. Despite this, clinical and preclinical research has greatly benefitted from the use of the nitric oxide donor, nitroglycerin (NTG), to model this disorder, dissect underlying mechanisms, and to facilitate the development and screening of effective therapeutics. NTG is capable of triggering a migraine attack, only in migraineurs or patients with a history of migraine and inducing migraine-like phenotypes in rodent models. It is however unclear to what extent NTG and NO, as its breakdown product, is a determinant factor in the underlying pathophysiology of migraine, and importantly, whether it really does facilitate the translation from the bench to the bedside, and vice-versa. This review provides an insight into the evidence supporting the strengths of this model, as well as its limitations, and shines a light into the possible role of NO-related mechanisms in altered molecular signalling pathways.

Unpredictable Sound Stress Model Causes Migraine-Like Behaviors in Mice With Sexual Dimorphism

Migraine represents one of the major causes of disability worldwide and is more prevalent in women; it is also related to anxiety symptoms. Stress, such as sound stress, is a frequently reported trigger in migraine patients, but the underlying mechanisms are not fully understood. However, it is known that patients with migraine have higher levels of plasma inflammatory cytokines and calcitonin gene-related peptide (CGRP). Stress mediated by unpredictable sound is already used as a model of painful sensitization, but migraine-like behaviors and sexual dimorphism have not yet been evaluated. This study characterized nociception and anxiety-related symptoms after the induction of sound stress in mice. C57BL/6 mice (20–30 g) were exposed to unpredictable sound stress for 3 days, nonconsecutive days. We observed enhanced plasma corticosterone levels on day 1 after stress induction. First, 7 days after the last stress session, mice developed hind paw and periorbital mechanical allodynia, grimacing pain behavior, anxiety-like symptoms, and reduced exploratory behavior. The nociceptive and behavioral alterations detected in this model were mostly shown in female stressed mice at day 7 post-stress. In addition, on day 7 post-stress nociception, these behaviors were consistently abolished by the CGRP receptor antagonist olcegepant (BIBN4096BS, 100 mg/kg by intraperitoneal route) in female and male stressed mice. We also demonstrated an increase in interleukine-6 (IL-6), tumor necrosis factor (TNF-α), and CGRP levels in stressed mice plasma, with female mice showing higher levels compared to male mice. This stress paradigm allows further preclinical investigation of mechanisms contributing to migraine-inducing pain.

B vitamins and their combination could reduce migraine headaches: A randomized double-blind controlled trial

Background: The B vitamins can potentially help prevent migraine. This study was designed to examine the effects of supplementation with thiamine (B1), pyridoxine (B6), cobalamin (B12), folic acid (B9), and a combination of these vitamins on women with episodic migraine (EM). Methods: This study was a double-blind, placebo-controlled, randomized, clinical trial conducted on 120 women with EM. The participants were divided into the 6 groups of B1 (n = 20), B6 (n = 20), B12 (n = 20), B9 (n = 20), vitamin B complex (n = 20), and placebo (n = 20). Subjects received 1 capsule daily for 12 weeks. As part of the baseline and post-intervention phases, paper-based headache diaries were used to record the number of abortive drugs consumed and the frequency of headache attacks, and the Migraine Disability Assessment Questionnaire (MIDAS) was used to assess migraine disability. Results: A 16-week study on women with EM revealed that the mean changes in the frequency of headache attacks decreased significantly in all vitamin groups in comparison with the placebo group (P < 0.001). In contrast to the placebo, there was also a significant improvement in the migraine disability score in each vitamin group (P < 0.001). The 12-week supplementation with vitamins B9, B1, B6, B12, and B complex also brought on a significant decrease in the use of abortive drugs compared to the placebo group (P = 0.032). Conclusion: The results of this study showed that B1, B6, B12, and B9, and a combination of these vitamins could be effective as an adjuvant in treatment and prophylaxis of EM. Further large trials with long-term follow-ups will be required to confirm our results.

Cardiovascular therapeutics: A new potential for anxiety treatment?

Besides the well‐recognized risk factors, novel conditions increasing cardiovascular morbidity and mortality are emerging. Undesirable emotions and behavior such as anxiety and depression, appear to participate in worsening cardiovascular pathologies. On the other hand, deteriorating conditions of the heart and vasculature result in disturbed mental and emotional health. The pathophysiological background of this bidirectional interplay could reside in an inappropriate activation of vegetative neurohormonal and other humoral systems in both cardiovascular and psychological disturbances. This results in circulus vitiosus potentiating mental and circulatory disorders. Thus, it appears to be of utmost importance to examine the alteration of emotions, cognition, and behavior in cardiovascular patients. In terms of this consideration, recognizing the potential of principal cardiovascular drugs to interact with the mental state in patients with heart or vasculature disturbances is unavoidable, to optimize their therapeutic benefit. In general, beta‐blockers, central sympatholytics, ACE inhibitors, ARBs, aldosterone receptor blockers, sacubitril/valsartan, and fibrates are considered to exert anxiolytic effect in animal experiments and clinical settings. Statins and some beta‐blockers appear to have an equivocal impact on mood and anxiety and ivabradine expressed neutral psychological impact. It seems reasonable to suppose that the knowledge of a patient's mood, cognition, and behavior, along with applying careful consideration of the choice of the particular cardiovascular drug and respecting its potential psychological benefit or harm might improve the individualized approach to the treatment of cardiovascular disorders.

Dual Inhibition of FAAH and MAGL Counteracts Migraine-like Pain and Behavior in an Animal Model of Migraine

The endocannabinoid system exerts an important role in pain processing and modulation. Modulation of the system with hydrolase inhibitors of anandamide (AEA) or 2-arachidonyl glycerol (2-AG) has proved effective in reducing migraine-like features in animal models of migraine. Here, we investigated the effect of dual inhibition of the AEA and 2-AG catabolic pathways in the nitroglycerin-based animal model of migraine. The dual inhibitor JZL195 was administered to rats 2 h after nitroglycerin or vehicle injection. Rats were then exposed to the open field test and the orofacial formalin test. At the end of the tests, they were sacrificed to evaluate calcitonin gene-related peptide (CGRP) serum levels and gene expression of CGRP and cytokines in the cervical spinal cord and the trigeminal ganglion. The dual inhibitor significantly reduced the nitroglycerin-induced trigeminal hyperalgesia and pain-associated behavior, possibly via cannabinoid 1 receptors-mediated action, but it did not change the hypomotility and the anxiety behaviors induced by nitroglycerin. The decreased hyperalgesia was associated with a reduction in CGRP and cytokine gene expression levels in central and peripheral structures and reduced CGRP serum levels. These data suggest an antinociceptive synergy of the endocannabinoid action in peripheral and central sites, confirming that this system participates in reduction of cephalic pain signals.

The cross-talk between dopaminergic and nitric oxide systems in the medial septal nucleus, and their distinct effects on anxiety-like behaviors in male rats

Anxiety disorders, which have a noticeable global prevalence and may be caused by many factors, include a spectrum of disorders that share features of excessive fear- and anxiety-related behavioral disturbances. Different brain areas and neurotransmitter systems have been under investigation for anxiety-related disorders. In this study, we investigated the possible interaction between the dopaminergic and nitric oxide (NO) neurotransmitter systems in the medial septal nucleus and their roles in anxiety-like behaviors using elevated plus-maze (EPM) test in male rats. Our results showed that: (i) both D1-and D2-like receptor agonists, SKF-38393 and quinpirole, augmented anxiety-like behaviors at their two highest applied doses in the EPM test; (ii) both D1-and D2-like receptor antagonists, SCH- 23390 and sulpiride, reduced anxiety-like behaviors at their two highest applied doses in the EPM test; (iii) L-Arginine, a NO precursor, increased anxiety-like behaviors, but L-NAME, a non-specific nitric oxide synthase (NOS) inhibitor, reduced them in the EPM test; (iv) L-NAME could not reverse the anxiety-like parameters produced by SKF-38393, but it significantly reduced the anxiety-like behaviors induced by quinpirole; (v) Neither SCH- 23390 nor sulpiride changed anxiety-related behaviors induced by L-Arginine. It can be concluded that both dopaminergic and nitric oxide systems in the medial septal nucleus are involved in modulating anxiety-like behaviors. While NO has an involvement in the exerted effects by the D2-like agonist, such effects were not observed at the applied range of the doses for D1-and D2-like antagonists.