Anxiolytic properties of N -acetylcysteine in mice

L-Cysteine: A promising nutritional supplement for alleviating anxiety disorders

Anxiety disorders are prevalent chronic psychological disease with complex pathogenic mechanisms. Current anxiolytics have limited efficacy and numerous side effects in many anxiety patients, highlighting the urgent need for new therapies. Recent research has been focusing on nutritional supplements, particularly amino acids, as potential therapies for anxiety disorders. Among these, L-Cysteine plays a crucial role in various biological processes. L-Cysteine exhibits antioxidant properties that can enhance the antioxidant functions of the central nervous system (CNS). Furthermore, metabolites of L-cysteine, such as glutathione and hydrogen sulfide have been shown to alleviate anxiety through distinct molecular mechanisms. Long-term administration of L-Cysteine has anxiolytic, antidepressant, and memory-improving effects. L-Cysteine depletion can lead to increased oxidative stress in the brain. This review delves into the potential mechanisms of L-Cysteine and its main products, glutathione (GSH) and hydrogen sulfide (H2S) in the management of anxiety and related diseases.

Marrubium vulgare Extract Improves Spatial Working Memory and Oxidative Stress Damage in Scopolamine-Treated Rats

Background

The cholinergic neuronal loss in the basal forebrain and increasing brain oxidative stress are one of the main features of the brain suffering from Alzheimer's disease. Marrubium vulgare (M. vulgare), commonly known as 'white horehound,' possesses a variety of valuable properties, such as antioxidative, anti-inflammatory, and antidiabetic activities. Moreover, it possesses neuromodulatory properties that could potentially impact short-term memory functions.

Objective

The present study was undertaken to investigate the preventive effects of water M. vulgare extract on working memory, cholinergic neurotransmission, and oxidative stress in rats with scopolamine (Sco)-induced dementia.

Methods

Male Wistar rats (200-250 g) were divided into four experimental groups. The plant extract was administered orally for 21 days, and Sco (2 mg/kg) was administered intraperitoneally for 11 consecutive days. The behavioral performance of the animals was evaluated by the T-maze test. The effect of the extract on acetylcholinesterase (AChE) activity and antioxidant status in cortex and hippocampus were also monitored.

Results

Our experimental data revealed that treatment with M. vulgare significantly increased the percentage of correct choices of rats with Sco-induced dementia in the T maze test (by 38%, p < 0.05). Additionally, it reduced AChE activity in the hippocampus (by 20%, p < 0.05) and alleviated oxidative stress induced by Sco, particularly in the cortex.

Conclusions

M. vulgare water extract demonstrated working memory preserving effect in rats with Sco-induced dementia, AChE inhibitory activity and in vivo antioxidant potential, and deserve further attention.

Effects of N-acetylcysteine and acetyl-L-carnitine on acute PTZ-induced seizures in larval and adult zebrafish

BACKGROUND

Epilepsy is a prevalent neurological disease, affecting approximately 1-2% of the global population. The hallmark of epilepsy is the occurrence of epileptic seizures, which are characterized by predictable behavioral changes reflecting the underlying neural mechanisms of the disease. Unfortunately, around 30% of patients do not respond to current pharmacological treatments. Consequently, exploring alternative therapeutic options for managing this condition is crucial. Two potential candidates for attenuating seizures are N-acetylcysteine (NAC) and Acetyl-L-carnitine (ALC), as they have shown promising neuroprotective effects through the modulation of glutamatergic neurotransmission.

METHODS

This study aimed to assess the effects of varying concentrations (0.1, 1.0, and 10 mg/L) of NAC and ALC on acute PTZ-induced seizures in zebrafish in both adult and larval stages. The evaluation of behavioral parameters such as seizure intensity and latency to the crisis can provide insights into the efficacy of these substances.

RESULTS

Our results indicate that both drugs at any of the tested concentrations were not able to reduce PTZ-induced epileptic seizures. On the other hand, the administration of diazepam demonstrated a notable reduction in seizure intensity and increased latencies to higher scores of epileptic seizures.

CONCLUSION

Consequently, we conclude that, under the conditions employed in this study, NAC and ALC do not exhibit any significant effects on acute seizures in zebrafish.

Potential Role of Glutathione Antioxidant Pathways in the Pathophysiology and Adjunct Treatment of Psychiatric Disorders

Oxidative stress is defined as the imbalance between the production of free radicals and their removal by antioxidants, leading to accumulation and subsequent organ and tissue damage. Antioxidant status and its role in the accumulation of free radicals has been observed in a number of psychological disorders. Glutathione is commonly referred to as the principal antioxidant of the brain and, therefore, plays a critical role in maintaining redox homeostasis. Reduced levels of glutathione in the brain increase its vulnerability to oxidative stress, and may be associated with the development and progression of several psychiatric disorders. Within this review, we focus on analyzing potential associations between the glutathione antioxidant pathway and psychiatric disorders: major depressive disorder, schizophrenia, bipolar disorder, and generalized anxiety disorder. Our research suggests that studies regarding these four disorders have shown decreased levels of GSH in association with diseased states; however, conflicting results note no significant variance in glutathione pathway enzymes and/or metabolites based on diseased state. In studying the potential of NAC administration as an adjunct therapy, various studies have shown NAC to augment therapy and/or aid in symptomatic management for psychiatric disorders, while contrasting results exist within the literature. Based on the conflicting findings throughout this review, there is room for study regarding the potential role of glutathione in the development and progression of psychiatric disorders. Our findings further suggest a need to study such pathways with consideration of the interactions with first-line pharmacotherapy, and the potential use of antioxidants as supplemental therapy.

A Maternal High-Fat Diet Causes Anxiety-Related Behaviors by Altering Neuropeptide Y1 Receptor and Hippocampal Volumes in Rat Offspring: the Potential Effect of N-Acetylcysteine

The children of obese mothers are known to have a high risk of obesity and metabolic disease and are prone to developing cognitive deficits, although the underlying mechanism is not yet fully understood. This study investigated the relationship between neuropeptide Y1 receptor (NPY1R) and anxiety-like behaviors in the hippocampi of male rat offspring exposed to maternal obesity and the potential neuroprotective effects of N-acetylcysteine (NAC). A maternal obesity model was created using a high-fat (60% k/cal) diet. NAC (150 mg/kg) was administered by intragastric gavage for 25 days in both the NAC and obesity + NAC (ObNAC) groups. All male rat offspring were subjected to behavioral testing on postnatal day 28, the end of the experiment. Stereological analysis was performed on hippocampal sections, while NPY1R expression was determined using immunohistochemical methods. Stereological data indicated significant decreases in the total volume of the hippocampus and CA1 and dentate gyrus (DG) regions in the obese (Ob) group (p < 0.01). Decreased NPY1R expression was observed in the Ob group hippocampus (p < 0.01). At behavioral assessments, the Ob group rats exhibited increased anxiety and less social interaction, although the ObNAC group rats exhibited stronger responses than the Ob group (p < 0.01). The study results show that NAC attenuated anxiety-like behaviors and NPY1R expression and also protected hippocampal volume against maternal obesity. The findings indicate that a decrease in NPY1R-positive neurons in the hippocampus of male rats due to maternal conditions may be associated with increased levels of anxiety and a lower hippocampal volume. Additionally, although there is no direct evidence, maintenance of NPY1R expression by NAC may be critical for regulating maternal obesity-induced anxiety-related behaviors and hippocampal structure.

Carbon Dots Derived from Os Draconis and Their Anxiolytic Effect

Background

At present, people are susceptible to developing depression and anxiety disorders in response to stress. However, there is no specific medicine for anxiety. Os Draconis (OD, named "Long gu" in Chinese) are fossilized bones that have been used in traditional Chinese medicine to treat neurological diseases for thousands of years. Thus, we conducted this study to determine the biological basis for the anxiolytic effect of OD.

Methods

In this study, novel carbon dots (OD-CDs) from OD decoctions were discovered and separated. OD-CDs were anatomized using nanomaterials characterization methods to characterize the morphological structure, optical properties, and functional group properties. Four behavioural tests were conducted to observe the behavioural activities of mice, including the open field test (OFT), light/dark box test (LDT), elevated plus maze test (EPMT), and novelty-suppressed feeding test (NSFT), to determine its anxiolytic effects. Moreover, we assessed the possible mechanisms of the OD-CDs by detecting hormones associated with the hypothalamic-pituitary-adrenal (HPA) axis.

Results

OD-CDs were spherical and monodispersed with a narrow size distribution between 1 and 5 nm and had a yield of 3.67%. OD-CDs increased the activity time of mice in the central zone in the OFT. The mice in the experimental group showed more frequent activity in the light compartment and the open arms, in LDT and EPMT, respectively. In addition, OD-CDs shortened the feeding latency in the NSFT. Furthermore, the results after OD-CDs intervention showed a significant increase in serum serotonin (5-HT) and norepinephrine (NE). In addition, the concentrations of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ATCH), and corticosterone (CORT) were decreased.

Conclusion

These results demonstrate a definite anxiolytic effect of OD-CDs and reveal the possible mechanism of action of OD-CDs' anxiolytic effect, which supports the research of OD for neurological disorders and a promising new trend of therapeutic approach and drug development.

N-acetylcysteine improves impulse control and attenuates relapse-like alcohol intake in long-term drinking rats

Increasing evidence suggests that individuals with alcohol use disorder (AUD) present with a disrupted glutamatergic system that underlies core components of addictive disorders, including drug relapse and low impulse control. N-acetylcysteine (NAC) is a cystine prodrug that has been found to promote glutamate homeostasis and drug abstinence. However, no studies to date have evaluated NAC's effect on impulsivity in substance use disorders. Here we determined whether NAC would decrease alcohol-intake behaviors, in addition to improving impulse control, in long-term alcohol drinking male Wistar-Han rats. Before the start of the experiments, all rats were exposed to long-term intermittent access to 20% ethanol for at least seven weeks. Next, in different groups of rats, the effect of NAC (60 and/or 90mg/kg) was evaluated on (i) voluntary alcohol drinking using a two-bottle free choice paradigm, (ii) the motivation to self-administer alcohol under a progressive ratio schedule of reinforcement, and (iii) relapse-like drinking using the alcohol deprivation effect model. Finally, (iv) NAC's effect on impulse control was evaluated using the five-choice serial reaction time task. Results showed that NAC administration at 90mg/kg significantly reduced relapse-like drinking and improved impulse control. In contrast, NAC had no effect on levels of alcohol drinking or motivation to drink alcohol. In conclusion, our findings continue to support the use of NAC as an adjuvant treatment for the maintenance of abstinence in AUD. Moreover, we provide evidence for NAC's efficacy in improving impulse control following drinking, which warrants further investigation in substance use settings.

Under or Absent Reporting of Light Stimuli in Testing of Anxiety-Like Behaviors in Rodents: The Need for Standardization

Behavioral neuroscience tests such as the Light/Dark Test, the Open Field Test, the Elevated Plus Maze Test, and the Three Chamber Social Interaction Test have become both essential and widely used behavioral tests for transgenic and pre-clinical models for drug screening and testing. However, as fast as the field has evolved and the contemporaneous involvement of technology, little assessment of the literature has been done to ensure that these behavioral neuroscience tests that are crucial to pre-clinical testing have well-controlled ethological motivation by the use of lighting (i.e., Lux). In the present review paper, N = 420 manuscripts were examined from 2015 to 2019 as a sample set (i.e., n = ~20–22 publications per year) and it was found that only a meager n = 50 publications (i.e., 11.9% of the publications sampled) met the criteria for proper anxiogenic and anxiolytic Lux reported. These findings illustrate a serious concern that behavioral neuroscience papers are not being vetted properly at the journal review level and are being released into the literature and public domain making it difficult to assess the quality of the science being reported. This creates a real need for standardizing the use of Lux in all publications on behavioral neuroscience techniques within the field to ensure that contributions are meaningful, avoid unnecessary duplication, and ultimately would serve to create a more efficient process within the pre-clinical screening/testing for drugs that serve as anxiolytic compounds that would prove more useful than what prior decades of work have produced. It is suggested that improving the standardization of the use and reporting of Lux in behavioral neuroscience tests and the standardization of peer-review processes overseeing the proper documentation of these methodological approaches in manuscripts could serve to advance pre-clinical testing for effective anxiolytic drugs. This report serves to highlight this concern and proposes strategies to proactively remedy them as the field moves forward for decades to come.

The Potential of N-Acetyl-L-Cysteine (NAC) in the Treatment of Psychiatric Disorders

N-acetyl-L-cysteine (NAC) is a compound of increasing interest in the treatment of psychiatric disorders. Primarily through its antioxidant, anti-inflammatory, and glutamate modulation activity, NAC has been investigated in the treatment of neurodevelopmental disorders, schizophrenia spectrum disorders, bipolar-related disorders, depressive disorders, anxiety disorders, obsessive compulsive-related disorders, substance-use disorders, neurocognitive disorders, and chronic pain. Whilst there is ample preclinical evidence and theoretical justification for the use of NAC in the treatment of multiple psychiatric disorders, clinical trials in most disorders have yielded mixed results. However, most studies have been underpowered and perhaps too brief, with some evidence of benefit only after months of treatment with NAC. Currently NAC has the most evidence of having a beneficial effect as an adjuvant agent in the negative symptoms of schizophrenia, severe autism, depression, and obsessive compulsive and related disorders. Future research with well-powered studies that are of sufficient length will be critical to better understand the utility of NAC in the treatment of psychiatric disorders.

N-acetylcysteine as a new prominent approach for treating psychiatric disorders

N-acetylcysteine (NAC) is a well-known and safe mucolytic agent, also used in patients with paracetamol overdose. In addition to these effects, recent preclinical and clinical studies have shown that NAC exerts beneficial effects on different psychiatric disorders. Many potential mechanisms have been proposed to underlie the therapeutic effects of NAC, including the regulation of several neurotransmitters, oxidative homeostasis, and inflammatory mediators. In this paper, we summarize the current knowledge on the ability of NAC to ameliorate symptoms and neuropathologies related to different psychiatric disorders, including attention deficit hyperactivity disorder, anxiety, bipolar disorder, depression, obsessive-compulsive disorder, obsessive-compulsive-related disorder, posttraumatic stress disorder, and schizophrenia. Although preclinical studies have shown a positive effect of NAC on animal models of psychiatric disorders, the clinical efficacy of NAC is not fully established. NAC remains a strong candidate for adjunct treatment for many psychiatric disorders, but additional preclinical and clinical studies are needed.

Water-Soluble Carbon Dots in Cigarette Mainstream Smoke: Their Properties and the Behavioural, Neuroendocrinological, and Neurotransmitter Changes They Induce in Mice

BACKGROUND

It is well known that smoking is harmful to health; however, it can also ameliorate anxiety. To date, it is unclear whether any nanoparticles found in cigarette mainstream smoke (CS) contribute to this effect.

AIM

The aim of this study was to assess the particle composition of CS to identify novel anti-anxiety components.

METHODS

Carbon dots (CDs) from CS (CS-CDs) were characterised using high-resolution transmission electron microscopy, Fourier-transform infrared, ultraviolet, fluorescence, X-ray photoelectron spectroscopy, X-ray diffraction and high-performance liquid chromatography. The anti-anxiety effects of CS-CDs in mouse models were evaluated and confirmed with the elevated plus maze and open-field tests.

RESULTS

The quantum yield of CS-CDs was 13.74%, with a composition of C, O, and N. In addition, the surface groups contained O-H, C-H, C=O, C-N, N-H, C-O-C, and COO- bonds. Acute toxicity testing revealed that CS-CDs had low in vitro and in vivo toxicity within a certain concentration range. The results of the elevated plus maze and open-field tests showed that CS-CDs had a significant anti-anxiety effect and a certain sedative effect in mice. The mechanism of these effects may be related to the decrease in glutamate levels and promotion of norepinephrine production in the mouse brain, and the decrease in dopamine in mouse serum due to CS-CDs.

CONCLUSION

CS-CDs may have anti-anxiety and certain sedative effects. This study provides a new perspective for a more comprehensive understanding of the components, properties, and functions of CS. Furthermore, it offers a novel target for the development of smoking cessation treatments, such as nicotine replacement therapy.

N-Acetylcysteine Attenuates the Anxiety-Like Behavior and Spatial Cognition Impairment Induced by Doxorubicin and Cyclophosphamide Combination Treatment in Rats

BACKGROUND

Cancer patients can suffer from psychological and cognitive disorders after chemotherapy, which influence quality of life.

OBJECTIVE

Oxidative stress may contribute to the psychological and cognitive disorders induced in rats by chemotherapy. In the present study, we examined the effects of N-acetylcysteine, an anti-oxidant, on anxiety-like behavior and cognitive impairment in rats treated with a combination of doxorubicin and cyclophosphamide.

METHODS

Rats were intraperitoneally injected with doxorubicin and cyclophosphamide once a week for 2 weeks. The light-dark test and the novel location recognition test were used to assess anxiety-like behavior and spatial cognition, respectively. The rats' hippocampal levels of glutathione (GSH) and glutathione disulfide (GSSG) were measured using a GSSG/GSH quantification kit.

RESULTS

Combined treatment with doxorubicin and cyclophosphamide produced anxiety-like behavior and cognitive impairment in rats. N-acetylcysteine reversed the anxiety-like behavior and inhibition of novel location recognition induced by the combination treatment. Furthermore, the combination of doxorubicin and cyclophosphamide significantly reduced the rats' hippocampal GSH/GSSG ratios. N-acetylcysteine reversed the reduction in the GSH/GSSG ratio seen in the doxorubicin and cyclophosphamide-treated rats.

CONCLUSION

These results suggest that N-acetylcysteine inhibits doxorubicin and cyclophosphamide-induced anxiety-like behavior and cognitive impairment by reducing oxidative stress in the hippocampus.

Effects of N-acetylcysteine treatment on ethanol's rewarding properties and dopaminergic alterations in mesocorticolimbic and nigrostriatal pathways

Recent reports have shown that N-acetylcysteine (N-AC) has beneficial effects in the treatment of cocaine and nicotine abuse. Considering the similar neurobiologic mechanisms involved in the development of addiction to different drugs, N-AC treatment could be useful in the treatment of ethanol abuse. The rewarding properties of the drugs of abuse plays an important role in the development of addiction and can be studied using the conditioned place preference (CPP) paradigm. Thus, to study the effects of N-AC treatment in the rewarding effects of ethanol, we investigated the effects of N-AC administration in the ethanol-induced CPP and neurochemical alterations within the mesocorticolimbic and the nigrostriatal dopaminergic pathways. Adult male Swiss mice were pretreated with N-AC (60 or 120 mg/kg intraperitoneal) and tested for the development, expression, or extinction of the ethanol-induced CPP. Another cohort of animals received N-AC (60 or 120 mg/kg intraperitoneal) 2-h before an acute administration of ethanol and had their brains removed for dopamine and its metabolites quantification in the mesocorticolimbic and nigrostriatal pathways. Pretreatment with N-AC (120 mg/kg) blocked the development of ethanol-induced CPP. On the other hand, N-AC at both doses did not alter the expression nor the extinction of ethanol-induced CPP. N-AC increased 3,4-dihydroxyphenylacetic acid content in the medial prefrontal cortex and dopaminergic turnover within the substantia nigra. Besides that, there was an increase in dopamine content in the nucleus accumbens of ethanol-treated animals. In summary, N-AC treatment blocked the development of ethanol CPP, without altering ethanol effects on dopaminergic neurotransmission.

Effects of N-acetylcysteine amide on anxiety and stress behavior in zebrafish

Anxiety disorders are highly prevalent and a leading cause of disability worldwide. Their etiology is related to stress, an adaptive response of the organism to restore homeostasis, in which oxidative stress and glutamatergic hyperactivity are involved. N-Acetylcysteine (NAC) is a multitarget approved drug proved to be beneficial in the treatment of various mental disorders. Nevertheless, NAC has low membrane permeability and poor bioavailability and its limited delivery to the brain may explain inconsistencies in the literature. N-Acetylcysteine amide (AD4) is a synthetic derivative of NAC in which the carboxyl group was modified to an amide. The amidation of AD4 improved lipophilicity and blood-brain barrier permeability and enhanced its antioxidant properties. The purpose of this study was to investigate the effects of AD4 on behavioral and biochemical parameters in zebrafish anxiety models. Neither AD4 nor NAC induced effects on locomotion and anxiety-related parameters in the novel tank test. However, in the light/dark test, AD4 (0.001 mg/L) increased the time spent in the lit side in a concentration 100 times lower than NAC (0.1 mg/L). In the acute restraint stress protocol, NAC and AD4 (0.001 mg/L) showed anxiolytic properties without meaningful effects on oxidative status. The study suggests that AD4 has anxiolytic effects in zebrafish with higher potency than the parent compound. Additional studies are warranted to characterize the anxiolytic profile of AD4 and its potential in the management of anxiety disorders.

Anxiolytic properties of compounds that counteract oxidative stress, neuroinflammation, and glutamatergic dysfunction: a review

Objective:

Anxiety disorders are highly prevalent and the efficacy of the available anxiolytic drugs is less than desired. Adverse effects also compromise patient quality of life and adherence to treatment. Accumulating evidence shows that the pathophysiology of anxiety and related disorders is multifactorial, involving oxidative stress, neuroinflammation, and glutamatergic dysfunction. The aim of this review was to evaluate data from animal studies and clinical trials showing the anxiolytic effects of agents whose mechanisms of action target these multiple domains.

Methods:

The PubMed database was searched for multitarget agents that had been evaluated in animal models of anxiety, as well as randomized double-blind placebo-controlled clinical trials of anxiety and/or anxiety related disorders.

Results:

The main multitarget agents that have shown consistent anxiolytic effects in various animal models of anxiety, as well in clinical trials, are agomelatine, N-acetylcysteine (NAC), and omega-3 fatty acids. Data from clinical trials are preliminary at best, but reveal good safety profiles and tolerance to adverse effects.

Conclusion:

Agomelatine, NAC and omega-3 fatty acids show beneficial effects in clinical conditions where mainstream treatments are ineffective. These three multitarget agents are considered promising candidates for innovative, effective, and better-tolerated anxiolytics.

Anxiolytic and anti-stress effects of acute administration of acetyl-L-carnitine in zebrafish

Studies have suggested that oxidative stress may contribute to the pathogenesis of mental disorders. In this context, molecules with antioxidant activity may be promising agents in the treatment of these deleterious conditions. Acetyl-L-carnitine (ALC) is a multi-target molecule that modulates the uptake of acetyl-CoA into the mitochondria during fatty acid oxidation, acetylcholine production, protein, and membrane phospholipid synthesis, capable of promoting neurogenesis in case of neuronal death. Moreover, neurochemical effects of ALC include modulation of brain energy and synaptic transmission of multiple neurotransmitters, including expression of type 2 metabotropic glutamate (mGlu2) receptors. The aim of this study was to investigate the effects of ALC in zebrafish by examining behavioral and biochemical parameters relevant to anxiety and mood disorders in zebrafish. ALC presented anxiolytic effects in both novel tank and light/dark tests and prevented the anxiety-like behavior induced by an acute stressor (net chasing). Furthermore, ALC was able to prevent the lipid peroxidation induced by acute stress in the zebrafish brain. The data presented here warrant further investigation of ALC as a potential agent in the treatment of neuropsychiatric disorders. Its good tolerability also subsidizes the additional studies necessary to assess its therapeutic potential in clinical settings.

N-acetylcysteine protects against motor, optomotor and morphological deficits induced by 6-OHDA in zebrafish larvae

Background

Parkinson's disease (PD) is the second most common neurodegenerative disorder. In addition to its highly debilitating motor symptoms, non-motor symptoms may precede their motor counterparts by many years, which may characterize a prodromal phase of PD. A potential pharmacological strategy is to introduce neuroprotective agents at an earlier stage in order to prevent further neuronal death. N-acetylcysteine (NAC) has been used against paracetamol overdose hepatotoxicity by restoring hepatic concentrations of glutathione (GSH), and as a mucolytic in chronic obstructive pulmonary disease by reducing disulfide bonds in mucoproteins. It has been shown to be safe for humans at high doses. More recently, several studies have evidenced that NAC has a multifaceted mechanism of action, presenting indirect antioxidant effect by acting as a GSH precursor, besides its anti-inflammatory and neurotrophic effects. Moreover, NAC modulates glutamate release through activation of the cystine-glutamate antiporter in extra-synaptic astrocytes. Its therapeutic benefits have been demonstrated in clinical trials for several neuropsychiatric conditions but has not been tested in PD models yet.

Methods

In this study, we evaluated the potential of NAC to prevent the damage induced by 6-hydroxydopamine (6-OHDA) on motor, optomotor and morphological parameters in a PD model in larval zebrafish.

Results

NAC was able to prevent the motor deficits (total distance, mean speed, maximum acceleration, absolute turn angle and immobility time), optomotor response impairment and morphological alterations (total length and head length) caused by exposure to 6-OHDA, which reinforce and broaden the relevance of its neuroprotective effects.

Discussion

NAC acts in different targets relevant to PD pathophysiology. Further studies and clinical trials are needed to assess this agent as a candidate for prevention and adjunctive treatment of PD.

N-acetyl cysteine reverses bio-behavioural changes induced by prenatal inflammation, adolescent methamphetamine exposure and combined challenges

RATIONALE

Schizophrenia is associated with prenatal inflammation and/or postnatal stressors such as drug abuse, resulting in immune-redox dysfunction. Antioxidants may offer therapeutic benefits.

OBJECTIVES

The objective of this study is to investigate N-acetyl cysteine (NAC) as a therapeutic antioxidant to reverse schizophrenia-like bio-behavioural changes in rats exposed to maternal immune activation (MIA), adolescent methamphetamine (MA) or a combination thereof.

METHODS

Sprague-Dawley offspring prenatally exposed to saline/lipopolysaccharide (LPS) received saline or MA (0.2-6 mg kg^-1 twice daily × 16 days) during adolescence and divided into LPS, MA and LPS + MA groups. Vehicle/NAC (150 mg kg^-1 × 14 days) was administered following MA/saline exposure on postnatal day 51-64. Social interaction, novel object recognition and prepulse inhibition (PPI) of startle, as well as regional brain monoamines, lipid peroxidation, plasma reactive oxygen species (ROS) and pro- and anti-inflammatory cytokines (TNF-α; IL-10), were assessed.

RESULTS

NAC reversed LPS, MA and LPS + MA-induced anxiety-like social withdrawal behaviours, as well as MA and LPS + MA-induced deficits in recognition memory. PPI deficits were evident in MA, LPS and LPS + MA models, with NAC reversing that following LPS + MA. NAC reversed LPS, MA and LPS + MA-induced frontal cortical dopamine (DA) and noradrenaline (NA) elevations, LPS and LPS + MA-induced frontal cortical 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT) and striatal NA deficits as well as LPS + MA-induced frontal cortical 5-HT turnover. Decreased IL-10 in the LPS, MA and LPS + MA animals, and increased TNF-α in the LPS and MA animals, was reversed with NAC. NAC also reversed elevated lipid peroxidation and ROS in the LPS and LPS + MA animals.

CONCLUSIONS

Prenatal LPS, LPS + postnatal MA challenge during adolescence, and to a lesser extent MA alone, promotes schizophrenia-like bio-behavioural changes later in life that are reversed by NAC, emphasizing therapeutic potential for schizophrenia and MA-associated psychosis. The nature and timing of the dual-hit are critical.