Heroin-Administered Mice Involved in Oxidative Stress and Exogenous Antioxidant-Alleviated Withdrawal Syndrome

The epigenetic signatures of opioid addiction and physical dependence are prevented by D-cysteine ethyl ester and betaine

We have reported that D,L-thiol esters, including D-cysteine ethyl ester (D-CYSee), are effective at overcoming opioid-induced respiratory depression (OIRD) in rats. Our on-going studies reveal that co-injections of D-CYSee with multi-day morphine injections markedly diminish spontaneous withdrawal that usually occurs after cessation of multiple injections of morphine in rats. Chronically administered opioids are known (1) to alter cellular redox status, thus inducing an oxidative state, and (2) for an overall decrease in DNA methylation, therefore resulting in the transcriptional activation of previously silenced long interspersed elements (LINE-1) retrotransposon genes. The first objective of the present study was to determine whether D-CYSee and the one carbon metabolism with the methyl donor, betaine, would maintain redox control and normal DNA methylation levels in human neuroblastoma cell cultures (SH-SY5Y) under overnight challenge with morphine (100 nM). The second objective was to determine whether D-CYSee and/or betaine could diminish the degree of physical dependence to morphine in male Sprague Dawley rats. Our data showed that overnight treatment with morphine reduced cellular GSH levels, induced mitochondrial damage, decreased global DNA methylation, and increased LINE-1 mRNA expression. These adverse effects by morphine, which diminished the reducing capacity and compromised the maintenance of the membrane potential of SH-SY5Y cells, was prevented by concurrent application of D-CYSee (100 µM) or betaine (300 µM). Furthermore, our data demonstrated that co-injections of D-CYSee (250 μmol/kg, IV) and to a lesser extent, betaine (250 μmol/kg, IV), markedly diminished the development of physical dependence induced by multi-day morphine injections (escalating daily doses of 10-30 mg/kg, IV), as assessed by the lesser number of withdrawal phenomena elicited by the injection of the opioid receptor antagonist, naloxone (1.5 mg/kg, IV). These findings provide evidence that D-CYSee and betaine prevent the appearance of redox alterations and epigenetic signatures commonly seen in neural cells involved in opioid physical dependence/addiction, and lessen development of physical dependence to morphine.

The cell-permeant antioxidant D-thiol ester D-cysteine ethyl ester overcomes physical dependence to morphine in male Sprague Dawley rats

The ability of morphine to decrease cysteine transport into neurons by inhibition of excitatory amino acid transporter 3 (EAA3) may be a key molecular mechanism underlying the acquisition of physical and psychological dependence to morphine. This study examined whether co-administration of the cell-penetrant antioxidant D-thiol ester, D-cysteine ethyl ester (D-CYSee), with morphine, would diminish the development of physical dependence to morphine in male Sprague Dawley rats. Systemic administration of the opioid receptor antagonist, naloxone (NLX), elicited pronounced withdrawal signs (e.g., wet-dog shakes, jumps, rears, circling) in rats that received a subcutaneous depot of morphine (150 mg/kg, SC) for 36 h and continuous intravenous infusion of vehicle (20 μL/h, IV). The NLX-precipitated withdrawal signs were reduced in rats that received an infusion of D-CYSee, but not D-cysteine, (both at 20.8 μmol/kg/h, IV) for the full 36 h. NLX elicited pronounced withdrawal signs in rats treated for 48 h with morphine (150 mg/kg, SC), plus continuous infusion of vehicle (20 μL/h, IV) that began at the 36 h timepoint of morphine treatment. The NLX-precipitated withdrawal signs were reduced in rats that received a 12 h infusion of D-CYSee, but not D-cysteine, (both at 20.8 μmol/kg/h, IV) that began at the 36 h timepoint of morphine treatment. These findings suggest that D-CYSee may attenuate the development of physical dependence to morphine and reverse established dependence to the opioid in male Sprague Dawley rats. Alternatively, D-CYSee may simply suppress the processes responsible for NLX-precipitated withdrawal. Nonetheless, D-CYSee and analogues may be novel therapeutics for the treatment of opioid use disorders.

Lipophilic analogues of D-cysteine prevent and reverse physical dependence to fentanyl in male rats

We examined whether co-injections of the cell-permeant D-cysteine analogues, D-cysteine ethyl ester (D-CYSee) and D-cysteine ethyl amide (D-CYSea), prevent acquisition of physical dependence induced by twice-daily injections of fentanyl, and reverse acquired dependence to these injections in freely-moving male Sprague Dawley rats. Injection of the opioid receptor antagonist, naloxone HCl (NLX, 1.5 mg/kg, IV), elicited a series of withdrawal phenomena that included cardiorespiratory and behavioral responses, and falls in body weight and body temperature, in rats that received 5 or 10 injections of fentanyl (125 μg/kg, IV), and the same number of vehicle co-injections. Regarding the development of physical dependence, the NLX-precipitated withdrawal phenomena were markedly reduced in fentanyl-injected rats that had received co-injections of D-CYSee (250 μmol/kg, IV) or D-CYSea (100 μmol/kg, IV), but not D-cysteine (250 μmol/kg, IV). Regarding reversal of established dependence to fentanyl, the NLX-precipitated withdrawal phenomena in rats that had received 10 injections of fentanyl (125 μg/kg, IV) was markedly reduced in rats that received co-injections of D-CYSee (250 μmol/kg, IV) or D-CYSea (100 μmol/kg, IV), but not D-cysteine (250 μmol/kg, IV), starting with injection 6 of fentanyl. This study provides evidence that co-injections of D-CYSee and D-CYSea prevent the acquisition of physical dependence, and reverse acquired dependence to fentanyl in male rats. The lack of effect of D-cysteine suggests that the enhanced cell-penetrability of D-CYSee and D-CYSea into cells, particularly within the brain, is key to their ability to interact with intracellular signaling events involved in acquisition to physical dependence to fentanyl.

The impact of chronic fentanyl administration on the cerebral cortex in mice: Molecular and histological effects

PURPOSE

Fentanyl, a fully synthetic opioid, is widely used for severe pain management and has a huge abuse potential for its psychostimulant effects. Unlike other opioids, the neurotoxic effects of chronic fentanyl administration are still unclear. In particular, little is known about its effect on the cerebral cortex. The current study aims to test the chronic toxicity of fentanyl in the mice model.

METHODS

Adult male Balb/c mice were chronically treated with low (0.05 mg/kg, i.p) and high (0.1 mg/kg, i.p) doses of fentanyl for 5 consecutive weeks, and various neurotoxic parameters, including apoptosis, oxidative stress, and neuroinflammatory response were assessed in the cortex. Potential histological as well as neurochemical changes were also evaluated.

RESULTS

The results of this study show that chronic fentanyl administration induced intense levels of apoptosis, oxidative stress, and neuroinflammation in the cerebral cortex. These findings were found to be correlated with histopathological characteristics of neural degeneration and white matter injury. Moreover, fentanyl administration was found to reduce the expression of both NMDA receptor subunits and dopamine receptors and elevate the level of epidermal growth factor (EGF).

CONCLUSION

Fentanyl administration induced neurotoxic effects in the mouse cerebral cortex that could be primarily mediated by the evoked oxidative-inflammatory response. The altered expression of NMDA receptors, dopamine receptors, and EGF suggests the pernicious effects of fentanyl addiction that may end in the development of toxic psychosis.

Amelioration of morphine withdrawal syndrome by systemic and intranasal administration of mesenchymal stem cell-derived secretome in preclinical models of morphine dependence

BACKGROUND

Morphine is an opiate commonly used in the treatment of moderate to severe pain. However, prolonged administration can lead to physical dependence and strong withdrawal symptoms upon cessation of morphine use. These symptoms can include anxiety, irritability, increased heart rate, and muscle cramps, which strongly promote morphine use relapse. The morphine-induced increases in neuroinflammation, brain oxidative stress, and alteration of glutamate levels in the hippocampus and nucleus accumbens have been associated with morphine dependence and a higher severity of withdrawal symptoms. Due to its rich content in potent anti-inflammatory and antioxidant factors, secretome derived from human mesenchymal stem cells (hMSCs) is proposed as a preclinical therapeutic tool for the treatment of this complex neurological condition associated with neuroinflammation and brain oxidative stress.

METHODS

Two animal models of morphine dependence were used to evaluate the therapeutic efficacy of hMSC-derived secretome in reducing morphine withdrawal signs. In the first model, rats were implanted subcutaneously with mini-pumps which released morphine at a concentration of 10 mg/kg/day for seven days. Three days after pump implantation, animals were treated with a simultaneous intravenous and intranasal administration of hMSC-derived secretome or vehicle, and withdrawal signs were precipitated on day seven by i.p. naloxone administration. In this model, brain alterations associated with withdrawal were also analyzed before withdrawal precipitation. In the second animal model, rats voluntarily consuming morphine for three weeks were intravenously and intranasally treated with hMSC-derived secretome or vehicle, and withdrawal signs were induced by morphine deprivation.

RESULTS

In both animal models secretome administration induced a significant reduction of withdrawal signs, as shown by a reduction in a combined withdrawal score. Secretome administration also promoted a reduction in morphine-induced neuroinflammation in the hippocampus and nucleus accumbens, while no changes were observed in extracellular glutamate levels in the nucleus accumbens.

CONCLUSION

Data presented from two animal models of morphine dependence suggest that administration of secretome derived from hMSCs reduces the development of opioid withdrawal signs, which correlates with a reduction in neuroinflammation in the hippocampus and nucleus accumbens.

L-cysteine ethyl ester prevents and reverses acquired physical dependence on morphine in male Sprague Dawley rats

The molecular mechanisms underlying the acquisition of addiction/dependence on morphine may result from the ability of the opioid to diminish the transport of L-cysteine into neurons via inhibition of excitatory amino acid transporter 3 (EAA3). The objective of this study was to determine whether the co-administration of the cell-penetrant L-thiol ester, L-cysteine ethyl ester (L-CYSee), would reduce physical dependence on morphine in male Sprague Dawley rats. Injection of the opioid-receptor antagonist, naloxone HCl (NLX; 1.5 mg/kg, IP), elicited pronounced withdrawal phenomena in rats which received a subcutaneous depot of morphine (150 mg/kg) for 36 h and were receiving a continuous infusion of saline (20 μL/h, IV) via osmotic minipumps for the same 36 h period. The withdrawal phenomena included wet-dog shakes, jumping, rearing, fore-paw licking, 360° circling, writhing, apneas, cardiovascular (pressor and tachycardia) responses, hypothermia, and body weight loss. NLX elicited substantially reduced withdrawal syndrome in rats that received an infusion of L-CYSee (20.8 μmol/kg/h, IV) for 36 h. NLX precipitated a marked withdrawal syndrome in rats that had received subcutaneous depots of morphine (150 mg/kg) for 48 h) and a co-infusion of vehicle. However, the NLX-precipitated withdrawal signs were markedly reduced in morphine (150 mg/kg for 48 h)-treated rats that began receiving an infusion of L-CYSee (20.8 μmol/kg/h, IV) at 36 h. In similar studies to those described previously, neither L-cysteine nor L-serine ethyl ester (both at 20.8 μmol/kg/h, IV) mimicked the effects of L-CYSee. This study demonstrates that 1) L-CYSee attenuates the development of physical dependence on morphine in male rats and 2) prior administration of L-CYSee reverses morphine dependence, most likely by intracellular actions within the brain. The lack of the effect of L-serine ethyl ester (oxygen atom instead of sulfur atom) strongly implicates thiol biochemistry in the efficacy of L-CYSee. Accordingly, L-CYSee and analogs may be a novel class of therapeutics that ameliorate the development of physical dependence on opioids in humans.

Ketogenic diet: a potential adjunctive treatment for substance use disorders

Substance use disorders (SUD) can lead to serious health problems, and there is a great interest in developing new treatment methods to alleviate the impact of substance abuse. In recent years, the ketogenic diet (KD) has shown therapeutic benefits as a dietary therapy in a variety of neurological disorders. Recent studies suggest that KD can compensate for the glucose metabolism disorders caused by alcohol use disorder by increasing ketone metabolism, thereby reducing withdrawal symptoms and indicating the therapeutic potential of KD in SUD. Additionally, SUD often accompanies increased sugar intake, involving neural circuits and altered neuroplasticity similar to substance addiction, which may induce cross-sensitization and increased use of other abused substances. Reducing carbohydrate intake through KD may have a positive effect on this. Finally, SUD is often associated with mitochondrial damage, oxidative stress, inflammation, glia dysfunction, and gut microbial disorders, while KD may potentially reverse these abnormalities and serve a therapeutic role. Although there is much indirect evidence that KD has a positive effect on SUD, the small number of relevant studies and the fact that KD leads to side effects such as metabolic abnormalities, increased risk of malnutrition and gastrointestinal symptoms have led to the limitation of KD in the treatment of SUD. Here, we described the organismal disorders caused by SUD and the possible positive effects of KD, aiming to provide potential therapeutic directions for SUD.

Mu opioid receptor-mediated release of endolysosome iron increases levels of mitochondrial iron, reactive oxygen species, and cell death

Objectives

Opioids including morphine and DAMGO activate mu-opioid receptors (MOR), increase intracellular reactive oxygen species (ROS) levels, and induce cell death. Ferrous iron (Fe2+) through Fenton-like chemistry increases ROS levels and endolysosomes are "master regulators of iron metabolism" and contain readily-releasable Fe2+ stores. However, mechanisms underlying opioid-induced changes in endolysosome iron homeostasis and downstream-signaling events remain unclear.

Methods

We used SH-SY5Y neuroblastoma cells, flow cytometry, and confocal microscopy to measure Fe2+ and ROS levels and cell death.

Results

Morphine and DAMGO de-acidified endolysosomes, decreased endolysosome Fe2+ levels, increased cytosol and mitochondria Fe2+ and ROS levels, depolarized mitochondrial membrane potential, and induced cell death; effects blocked by the nonselective MOR antagonist naloxone and the selective MOR antagonist β-funaltrexamine (β-FNA). Deferoxamine, an endolysosome-iron chelator, inhibited opioid agonist-induced increases in cytosolic and mitochondrial Fe2+ and ROS. Opioid-induced efflux of endolysosome Fe2+ and subsequent Fe2+ accumulation in mitochondria were blocked by the endolysosome-resident two-pore channel inhibitor NED-19 and the mitochondrial permeability transition pore inhibitor TRO.

Conclusions

Opioid agonist-induced increases in cytosolic and mitochondrial Fe2+ and ROS as well as cell death appear downstream of endolysosome de-acidification and Fe2+ efflux from the endolysosome iron pool that is sufficient to affect other organelles.

Ferulic acid-loaded nanostructure prevents morphine reinstatement: the involvement of dopamine system, NRF2, and ΔFosB in the striatum brain area of rats

Morphine is among the most powerful analgesics and pain-relieving agents. However, its addictive properties limit their medical use because patients may be susceptible to abuse and reinstatement. Morphine addiction occurs because of dopamine release in the mesolimbic brain area, implying in an increase in oxidative stress. Ferulic acid (FA), a phenolic phytochemical found in a variety of foods, has been reported to exert antioxidant and neuroprotective effects; however, its low bioavailability makes its nano-encapsulated form a promising alternative. This study aimed to evaluate the protective effects of a novel nanosystem with FA on morphine reinstatement and the consequent molecular neuroadaptations and oxidative status in the mesolimbic region. Rats previously exposed to morphine in conditioned place preference (CPP) paradigm were treated with ferulic acid-loaded nanocapsules (FA-Nc) or nonencapsulated FA during morphine-preference extinction. Following the treatments, animals were re-exposed to morphine to induce the reinstatement. While morphine-preference extinction was comparable among all experimental groups, FA-Nc treatment prevented morphine reinstatement. In the dorsal striatum, while morphine exposure increased lipid peroxidation (LP) and reactive species (RS), FA-Nc decreased LP and FA decreased RS levels. Morphine exposure increased the dopaminergic markers (D1R, D3R, DAT) and ΔFosB immunoreactivity in the ventral striatum; however, FA-Nc treatment decreased D1R, D3R, and ΔFosB and increased D2R, DAT, and NRF2. In conclusion, FA-Nc treatment prevented the morphine reinstatement, promoted antioxidant activity, and modified the dopaminergic neurotransmission, NRF2, and ΔFosB, what may indicate a neuroprotective and antioxidant role of this nanoformulation.

Transcriptomics and metabolomics together reveal the underlying mechanism of heroin hepatotoxicity

Researches on heroin are more about addiction and some infectious diseases it causes, but liver fibrosis caused by heroin abuse and the mechanism of heroin hepatotoxicity in addicts are ignored. To explore the mechanism of heroin hepatotoxicity, mice in heroin group were intraperitoneally injected by heroin (10 mg/kg) once a day for 14 consecutive days, while mice in heroin withdraw group underwent another 7 days without heroin administration after the same treatment as heroin group. The levels of alanine aminotransferase （ALT）and aspartate aminotransferase （AST） in serum, as biochemical indexes, were applied to evaluate liver damage. H & E staining and oil red O staining were used to observe the pathological changes of liver. Transcriptomics and metabolomics were applied to detect genes and metabolites in livers. The results of biochemical analysis and pathological examination showed that heroin induced liver damage and lipid loss in mice, and these mice did not return to normal completely after a short-term withdrawal. A total of 511 differential genes and 78 differential metabolites were identified by transcriptomics and metabolomics. These differential genes and metabolites were significantly enriched in pathways like lipid metabolism, arachidonic acid metabolism, glutathione metabolism, TCA cycle. And after undergoing 7-day withdrawal of heroin, most of the above differential genes and metabolites did not return to normal. Our study revealed the hepatotoxicity of heroin and that short-term withdrawal of heroin did not fully restore liver function. In addition, transcriptomics and metabolomics revealed that lipid metabolism and arachidonic acid metabolism may be potential therapeutic targets of heroin hepatotoxicity, providing a basis for the treatment of heroin addiction patients in the future.

Inflammatory, oxidative stress and cognitive functions in patients under maintenance treatment with methadone or buprenorphine and healthy subjects

BACKGROUND

Methadone and buprenorphine which are widely used for opioid maintenance treatment can affect redox status and also brain functions. The present study aimed to compare inflammation, oxidative stress, and cognitive function in methadone maintenance patients (MMP), buprenorphine maintenance patients (BMP), and healthy participants.

METHOD

Oxidative- antioxidant markers, inflammatory factors were investigated in MMP (n = 30), BMP (n = 30), and healthy participants (n = 30) by evaluating the ferritin, malondialdehyde (MDA), total antioxidant capacity (TAC), and also High-sensitivity C-reactive protein (hs-CRP). Also, executive function was evaluated using Wisconsin Card Sorting Test (WCST).

FINDINGS

MMP and BMP showed impairment in executive function compared to the healthy participants. Both buprenorphine and methadone treatments induced oxidative stress. The ferritin level in BMP was significantly lower compared to MMP and healthy participants (P = 0.01). There was a significant difference between control and MMP and BMP (P > 0.0001) in terms of hs-CRP level. BMP had the highest and healthy participant's lowest MDA level (P < 0.001). The TAC levels in BMP were lower than in MMP (p = 0.002) and healthy participants (p = 0.001). Finally, executive function was significantly correlated with oxidative-antioxidant status.

DISCUSSION

Both methadone and buprenorphine induced severe oxidative activity (especially buprenorphine) and cognitive deficits compared to healthy participants. Stress oxidative can affect normal brain activity and consequently cognitive functions. It's suggested that concomitant antioxidant administration with buprenorphine or methadone can potentially enhance their beneficial action by regulating blood redox status.

Crossroads of Drug Abuse and HIV Infection: Neurotoxicity and CNS Reservoir

Drug abuse is a common comorbidity in people infected with HIV. HIV-infected individuals who abuse drugs are a key population who frequently experience suboptimal outcomes along the HIV continuum of care. A modest proportion of HIV-infected individuals develop HIV-associated neurocognitive issues, the severity of which further increases with drug abuse. Moreover, the tendency of the virus to go into latency in certain cellular reservoirs again complicates the elimination of HIV and HIV-associated illnesses. Antiretroviral therapy (ART) successfully decreased the overall viral load in infected people, yet it does not effectively eliminate the virus from all latent reservoirs. Although ART increased the life expectancy of infected individuals, it showed inconsistent improvement in CNS functioning, thus decreasing the quality of life. Research efforts have been dedicated to identifying common mechanisms through which HIV and drug abuse lead to neurotoxicity and CNS dysfunction. Therefore, in order to develop an effective treatment regimen to treat neurocognitive and related symptoms in HIV-infected patients, it is crucial to understand the involved mechanisms of neurotoxicity. Eventually, those mechanisms could lead the way to design and develop novel therapeutic strategies addressing both CNS HIV reservoir and illicit drug use by HIV patients.

Melatonin attenuates morphine-induced conditioned place preference in Wistar rats

PURPOSE

Morphine is the predominantly used drug for postoperative and cancer pain management. However, the abuse potential of morphine is the primary disadvantage of using opioids in pain management. Melatonin is a neurohormone synthesized in the pineal gland and is involved in circadian rhythms in mammals, as well as other physiological functions. Melatonin provenly attenuates alcohol-seeking and relapse behaviors in rats. Therefore, we aimed to investigate the involvement of the melatonergic system in attenuating morphine dependence.

MATERIALS AND METHODS

Male Wistar rats were divided into three groups: control, morphine, and morphine + melatonin. Animals were habituated for 3 days, and the initial preference was evaluated. Following the initial preference, the control group received the vehicle and was placed for a 45-min session in the assigned chamber every day, alternating between the two chambers, for 8 days. The morphine group received a morphine injection (5 mg/kg, IP) and was placed for a 45-min session in the white chamber, for a total of four sessions. The morphine + melatonin group received the morphine injection (5 mg/kg, IP) for a total of four sessions over an 8-day period. In the posttest session, the control and morphine groups received a vehicle injection 30 min before placement in the conditioned place preference (CPP). The morphine + melatonin group received a single injection of melatonin (50 mg/kg, IP) 30 min before the preference test.

RESULTS

Statistical analysis revealed that repeated administration of morphine for four sessions produced a significant increase in the CPP score in the morphine group compared to the control group. However, a single melatonin injection administered 30 min before the posttest attenuated morphine-seeking behavior and reduced morphine-induced place preference.

CONCLUSION

These findings provide novel evidence for the role of the melatonergic system as a potential target in modulating morphine-seeking behavior.

Plasma metabolites changes in male heroin addicts during acute and protracted withdrawal

BACKGROUND

Heroin addiction and withdrawal have been associated with an increased risk for infectious diseases and psychological complications. However, the changes of metabolites in heroin addicts during withdrawal remain largely unknown.

METHODS

A total of 50 participants including 20 heroin addicts with acute abstinence stage, 15 with protracted abstinence stage and 15 healthy controls, were recruited. We performed metabolic profiling of plasma samples based on ultraperformance liquid chromatography coupled to tandem mass spectrometry to explore the potential biomarkers and mechanisms of heroin withdrawal.

RESULTS

Among the metabolites analyzed, omega-6 polyunsaturated fatty acids (linoleic acid, dihomo-gamma-linolenic acid, arachidonic acid, n-6 docosapentaenoic acid), omega-3 polyunsaturated fatty acids (docosahexaenoic acid, docosapentaenoic acid), aromatic amino acids (phenylalanine, tyrosine, tryptophan), and intermediates of the tricarboxylic acid cycle (oxoglutaric acid, isocitric acid) were significantly reduced during acute heroin withdrawal. Although majority of the metabolite changes could recover after months of withdrawal, the levels of alpha-aminobutyric acid, alloisoleucine, ketoleucine, and oxalic acid do not recover.

CONCLUSIONS

In conclusion, the plasma metabolites undergo tremendous changes during heroin withdrawal. Through metabolomic analysis, we have identified links between a framework of metabolic perturbations and withdrawal stages in heroin addicts.

Viral vector-mediated gene therapy for opioid use disorders

Chronic exposure to opioids typically results in adverse consequences. Opioid use disorder (OUD) is a disease of the CNS with behavioral, psychological, neurobiological, and medical manifestations. OUD induces a variety of changes of neurotransmitters/neuropeptides in the nervous system. Existing pharmacotherapy, such as opioid maintenance therapy (OMT) is the mainstay for the treatment of OUD, however, current opioid replacement therapy is far from effective for the majority of patients. Pharmacological therapy for OUD has been challenging for many reasons including debilitating side-effects. Therefore, developing an effective, non-pharmacological approach would be a critical advancement in improving and expanding treatment for OUD. Viral vector mediated gene therapy provides a potential new approach for treating opioid abused patients. Gene therapy can supply targeting gene products directly linked to the mechanisms of OUD to restore neurotransmitter and/or neuropeptides imbalance, and avoid the off-target effects of systemic administration of drugs. The most commonly used viral vectors in rodent studies of treatment of opioid-used disorder are based on recombinant adenovirus (AV), adeno-associated virus (AAV), lentiviral (LV) vectors, and herpes simplex virus (HSV) vectors. In this review, we will focus on the recent progress of viral vector mediated gene therapy in OUD, especially morphine tolerance and withdrawal.

The effect of codeine administration on oxidative stress biomarkers and the expression of the neuron-specific enolase in the brain of Wistar rats

The study aimed to assess the effects of codeine medication on some oxidative stress parameters and how it affects the expression of enolase in neuronal cells. The codeine medication used for the study was Archilin™ with codeine syrup and dihydrocodeine 30 mg. The study used 30 male Wistar rats which were grouped in five: A, B, C, D, and E (n = 6), while treatments were administered for 21 days. Based on the LD₅₀s of 6.09 ml/kg body weight (b.wt.) Archilin™ with codeine syrup and 3.145 mg/kg b.wt. dihydrocodeine, group A served as control and were given normal saline; groups B and C were treated with 1 mg/kg and 2 mg/kg b.wt. dihydrocodeine, respectively; while groups D and E were treated with 2 ml/kg and 4 ml/kg b.wt. Archilin™ with codeine syrup, respectively. After treatments, animals were sacrificed via cervical dislocation and the brains were harvested and prepared for determination of oxidative stress biomarkers as well as immunohistochemical studies of neuron-specific enolase (NSE) to assess for neuronal cell integrity. Significantly decreased mean values (p < 0.05) of superoxide dismutase (SOD) and catalase (CAT) activities were observed while malondialdehyde (MDA) is significantly increased (p < 0.05) among treated groups. The expression of enolase was downregulated in treatment groups when compared to control. Animals in group A which are control showed strong staining intensity of the prefrontal cortex compared to groups C, D, and E which showed mild staining. The scoring of group A for cerebellum showed strong staining intensity, groups B and C showed mild staining, while groups D and E showed weak staining intensity. From the findings of this study, prolonged codeine syrup administration causes oxidative stress and this affects the expression of enolase in neuronal cells resulting in glucose hypometabolism which eventually results in functional brain failure.

A Novel Precision Approach to Overcome the "Addiction Pandemic" by Incorporating Genetic Addiction Risk Severity (GARS) and Dopamine Homeostasis Restoration

This article describes a unique therapeutic precision intervention, a formulation of enkephalinase inhibitors, enkephalin, and dopamine-releasing neuronutrients, to induce dopamine homeostasis for detoxification and treatment of individuals genetically predisposed to developing reward deficiency syndrome (RDS). The formulations are based on the results of the addiction risk severity (GARS) test. Based on both neurogenetic and epigenetic evidence, the test evaluates the presence of reward genes and risk alleles. Existing evidence demonstrates that the novel genetic risk testing system can successfully stratify the potential for developing opioid use disorder (OUD) related risks or before initiating opioid analgesic therapy and RDS risk for people in recovery. In the case of opioid use disorders, long-term maintenance agonist treatments like methadone and buprenorphine may create RDS, or RDS may have been in existence, but not recognized. The test will also assess the potential for benefit from medication-assisted treatment with dopamine augmentation. RDS methodology holds a strong promise for reducing the burden of addictive disorders for individuals, their families, and society as a whole by guiding the restoration of dopamine homeostasisthrough anti-reward allostatic neuroadaptations. WC 175.

Sintocalmy, a Passiflora incarnata Based Herbal, Attenuates Morphine Withdrawal in Mice

Chronic opioid use changes brain chemistry in areas related to reward processes, memory, decision-making, and addiction. Both neurons and astrocytes are affected, ultimately leading to dependence. Passiflora incarnata L. (Passifloraceae) is the basis of frequently used herbals to manage anxiety and insomnia, with proven central nervous system depressant effects. Anti-addiction properties of P. incarnata have been reported. The aim of this study was to investigate the effect of a commercial extract of Passiflora incarnata (Sintocalmy®, Aché Laboratory) in the naloxone-induced jumping mice model of morphine withdrawal. In addition, glial fibrillary acidic protein (GFAP) and S100 calcium-binding protein B (S100B) levels were assessed in the frontal cortex and hippocampus, and DNA damage was verified on blood cells. In order to improve solubilization a Sintocalmy methanol extract (SME) was used. SME is mainly composed by flavonoids isovitexin and vitexin. The effects of SME 50, 100 and 200 mg/kg (i.p.) were evaluated in the naloxone-induced withdrawal syndrome in mice. SME 50 and SME 100 mg/kg decreased naloxone-induced jumping in morphine-dependent mice without reducing locomotor activity. No alterations were found in GFAP levels, however SME 50 mg/kg prevented the S100B increase in the frontal cortex and DNA damage. This study shows anti-addiction effects for a commercial standardized extract of P. incarnata and suggests the relevance of proper clinical assessment.

Glutathione peroxidase-1 and neuromodulation: Novel potentials of an old enzyme

Glutathione peroxidase (GPx) acts in co-ordination with other signaling molecules to exert its own antioxidant role. We have demonstrated the protective effects of GPx,/GPx-1, a selenium-dependent enzyme, on various neurodegenerative disorders (i.e., Parkinson's disease, Alzheimer's disease, cerebral ischemia, and convulsive disorders). In addition, we summarized the recent findings indicating that GPx-1 might play a role as a neuromodulator in neuropsychiatric conditions, such as, stress, bipolar disorder, schizophrenia, and drug intoxication. In this review, we attempted to highlight the mechanistic scenarios mediated by the GPx/GPx-1 gene in impacting these neurodegenerative and neuropsychiatric disorders, and hope to provide new insights on the therapeutic interventions against these disorders.

Glutathione and Glutathione-Like Sequences of Opioid and Aminergic Receptors Bind Ascorbic Acid, Adrenergic and Opioid Drugs Mediating Antioxidant Function: Relevance for Anesthesia and Abuse

Opioids and their antagonists alter vitamin C metabolism. Morphine binds to glutathione (l-γ-glutamyl-l-cysteinyl-glycine), an intracellular ascorbic acid recycling molecule with a wide range of additional activities. The morphine metabolite morphinone reacts with glutathione to form a covalent adduct that is then excreted in urine. Morphine also binds to adrenergic and histaminergic receptors in their extracellular loop regions, enhancing aminergic agonist activity. The first and second extracellular loops of adrenergic and histaminergic receptors are, like glutathione, characterized by the presence of cysteines and/or methionines, and recycle ascorbic acid with similar efficiency. Conversely, adrenergic drugs bind to extracellular loops of opioid receptors, enhancing their activity. These observations suggest functional interactions among opioids and amines, their receptors, and glutathione. We therefore explored the relative binding affinities of ascorbic acid, dehydroascorbic acid, opioid and adrenergic compounds, as well as various control compounds, to glutathione and glutathione-like peptides derived from the extracellular loop regions of the human beta 2-adrenergic, dopamine D1, histamine H1, and mu opioid receptors, as well as controls. Some cysteine-containing peptides derived from these receptors do bind ascorbic acid and/or dehydroascorbic acid and the same peptides generally bind opioid compounds. Glutathione binds not only morphine but also naloxone, methadone, and methionine enkephalin. Some adrenergic drugs also bind to glutathione and glutathione-like receptor regions. These sets of interactions provide a novel basis for understanding some ways that adrenergic, opioid and antioxidant systems interact during anesthesia and drug abuse and may have utility for understanding drug interactions.

Proteomic analysis of protein composition of rat hippocampus exposed to morphine for 10 days; comparison with animals after 20 days of morphine withdrawal

Opioid addiction is recognized as a chronic relapsing brain disease resulting from repeated exposure to opioid drugs. Cellular and molecular mechanisms underlying the ability of organism to return back to the physiological norm after cessation of drug supply are not fully understood. The aim of this work was to extend our previous studies of morphine-induced alteration of rat forebrain cortex protein composition to the hippocampus. Rats were exposed to morphine for 10 days and sacrificed 24 h (groups +M10 and −M10) or 20 days after the last dose of morphine (groups +M10/−M20 and −M10/−M20). The six altered proteins (≥2-fold) were identified in group (+M10) when compared with group (−M10) by two-dimensional fluorescence difference gel electrophoresis (2D-DIGE). The number of differentially expressed proteins was increased to thirteen after 20 days of the drug withdrawal. Noticeably, the altered level of α-synuclein, β-synuclein, α-enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was also determined in both (±M10) and (±M10/−M20) samples of hippocampus. Immunoblot analysis of 2D gels by specific antibodies oriented against α/β-synucleins and GAPDH confirmed the data obtained by 2D-DIGE analysis. Label-free quantification identified nineteen differentially expressed proteins in group (+M10) when compared with group (−M10). After 20 days of morphine withdrawal (±M10/−M20), the number of altered proteins was increased to twenty. We conclude that the morphine-induced alteration of protein composition in rat hippocampus after cessation of drug supply proceeds in a different manner when compared with the forebrain cortex. In forebrain cortex, the total number of altered proteins was decreased after 20 days without morphine, whilst in hippocampus, it was increased.

Effect of fentanyl and its three novel analogues on biochemical, oxidative, histological, and neuroadaptive markers after sub-acute exposure in mice

AIMS

Comparative sub-acute toxicity, including tolerance and dependence potential of fentanyl and its three novel and potent analogues was determined in mice.

MAIN METHODS

Comparative sub-acute (21 d, intraperitoneal; 1/10 LD₅₀) toxicity of fentanyl and its three novel analogues viz., N-(1-(2-phenoxyethyl)-4-piperidinyl) propionanilide (2), N-isopropyl-3-(4-(N-phenylpropionamido)piperidin-1-yl)propanamide (5), and N-t-butyl-3-(4-(N-phenylpropionamido)piperidin-1-yl)propanamide (6) was determined in mice. Animals were observed for additional seven days to assess the recovery. The brain, liver and kidney toxicity was assessed on the basis of various biochemical, oxidative, histological, and neuroadaptive markers. The expression levels of key neuronal markers associated with drug tolerance and dependence were investigated by western blot and immunohistochemistry.

KEY FINDINGS

Fentanyl and its analogues caused abnormal levels of liver and kidney specific biomarkers in plasma. Brain malondialdehyde (MDA) levels were raised by all the treatments and kidney MDA level by analogue 6 (21 d). Reduced glutathione levels in brain, liver, and kidney were diminished by all the treatments (21 & 28 d) and a significant change in the levels of antioxidant enzymes was also produced mainly after 21 d. The deleterious effects of fentanyl and its analogues were further substantiated by corresponding histopathological changes in brain, liver and kidney (21 & 28 d). These compounds were also found to produce neuroadaptive changes as evidenced by the increased expression levels of c-Fos, glucocorticoid receptor, N-methyl-d-aspartate receptor1 and μ-opioid receptor (21 & 28 d).

SIGNIFICANCE

Three novel analogues of fentanyl were envisaged to have alternative therapeutic potentials. However, their comparative sub-acute toxicity revealed undesirable side effects, thereby masking their therapeutic ability.

Oxidative stress enzymes are changed in opioid abusers and multidrug abusers

The current study was designed to measure malondialdehyde level (MDA), super oxide dismutase (SOD) activity and COX-2 protein level in the prefrontal cortex (PFC) of drug-abusers. A total of 101 male drug abusers and 13 control subjects were gathered from the Iranian Legal Medicine center, Kahrizak, Tehran. Kind of death was determined by forensic pathologists, and the kind of drugs of abuse was detected using hair analysis. The medial prefrontal cortex (mPFC), lateral prefrontal cortex (lPFC), and orbitofrontal cortex (OFC) were dissected and were kept at -80 °C, until starting the assays. Our results indicated that the level of MDA was increased in the mPFC, lPFC and OFC of pure-opioid and multi-drug abusers compared with the control group. The SOD activity was reduced in the mPFC, lPFC and OFC of abusers in comparison to the control group. The protein level of COX-2 was decreased in the mPFC and lPFC of multi-drug abusers compared with the control group. This elevation in oxidative stress might be due to the increase of dopamine (as a consequence of drug abuse) or the direct effect of opioids and other drugs of abuse on oxidative agents. Antioxidant agents may be useful in preventing the damaging effect of oxidative agents in the brain of drug-addicted persons.

Effect of Severity of Opiate Use on Cardiometabolic Profile of Chronic Opiate Dependents of Western Rajasthan

Lack of cardiometabolic profile data based on severity of opiate dependence for opiate abusers. The study aimed to evaluate the effect severity of opiate abuse on the cardiometabolic profile of male opiate abusers without co-morbidities. The study included 30 healthy controls (HCs), 90 prospective chronic opiate (opium and heroin) abusers, with and without co-dependence of smoking and tobacco-chewing. The subjects were categorized based on severity of opiate dependence questionnaire (SODQ) and metabolic syndrome (MS) based on NCEP ATP-III criteria and fasting blood samples analyzed for sugar, insulin, insulin resistance (IR), lipid profile, Hs-CRP and total antioxidant capacity (TAC). There was higher prevalence of MS in opiate abusers as compared to HCs. Majority of the patients fell in grade 2 and 3 of severity. There was significant difference across groups for WHR (p < 0.001), SBP (p < 0.03), FBS (p < 0.001), insulin (p < 0.02), IR (p < 0.03) and TAC (p < 0.01). Multiple regression analysis of SODQ grades 2 and 3 independently predicted TAC by Hs-CRP (p = 0.032 and 0.042). There was a significant correlation of TAC with serum insulin, IR and Hs-CRP in SODQ grade 2 and serum insulin and Hs-CRP in SODQ grade 3. Chronic opiate abuse is not benign and predisposes abusers to cardiometabolic risk with increasing severity of dependence, owing to oxidative stress and chronic low-grade inflammation.

Supraphysiologic-dose anabolic-androgenic steroid use: A risk factor for dementia?

Supraphysiologic-dose anabolic-androgenic steroid (AAS) use is associated with physiologic, cognitive, and brain abnormalities similar to those found in people at risk for developing Alzheimer's Disease and its related dementias (AD/ADRD), which are associated with high brain β-amyloid (Aβ) and hyperphosphorylated tau (tau-P) protein levels. Supraphysiologic-dose AAS induces androgen abnormalities and excess oxidative stress, which have been linked to increased and decreased expression or activity of proteins that synthesize and eliminate, respectively, Aβ and tau-P. Aβ and tau-P accumulation may begin soon after initiating supraphysiologic-dose AAS use, which typically occurs in the early 20s, and their accumulation may be accelerated by other psychoactive substance use, which is common among non-medical AAS users. Accordingly, the widespread use of supraphysiologic-dose AAS may increase the numbers of people who develop dementia. Early diagnosis and correction of sex-steroid level abnormalities and excess oxidative stress could attenuate risk for developing AD/ADRD in supraphysiologic-dose AAS users, in people with other substance use disorders, and in people with low sex-steroid levels or excess oxidative stress associated with aging.

Buprenorphine and Methadone as Opioid Maintenance Treatments for Heroin-Addicted Patients Induce Oxidative Stress in Blood

Buprenorphine and methadone are two substances widely used in the substitution treatment of patients who are addicted to opioids. Although it is known that they partly act efficiently towards this direction, there is no evidence regarding their effects on the redox status of patients, a mechanism that could potentially improve their action. Therefore, the aim of the present investigation was to examine the impact of buprenorphine and methadone, which are administered as substitutes to heroin-dependent patients on specific redox biomarkers in the blood. From the results obtained, both the buprenorphine (n = 21) and the methadone (n = 21) groups exhibited oxidative stress and compromised antioxidant defence. This was evident by the decreased glutathione (GSH) concentration and catalase activity in erythrocytes and the increased concentrations of thiobarbituric acid reactive substances (TBARS) and protein carbonyls in the plasma, while there was no significant alteration of plasma total antioxidant capacity (TAC) compared to the healthy individuals (n = 29). Furthermore, methadone revealed more severe oxidant action compared to buprenorphine. Based on relevant studies, the tested substitutes mitigate the detrimental effects of heroin on patient redox status; still it appears that they need to be boosted. Therefore, concomitant antioxidant administration could potentially enhance their beneficial action, and most probably, buprenorphine that did not induce oxidative stress in such a severe mode as methadone, on the regulation of blood redox status.

Effects of glucosamine against morphine-induced antinociceptive tolerance and dependence in mice

BACKGROUND

The most important limitations of morphine in pain therapy are its tolerance and dependence. In this study, we evaluated the protective effect of glucosamine against morphine-induced tolerance and dependence in mice.

METHODS

Mice received twice daily morphine (20 mg/kg, s.c.) alone, or along with orally administered glucosamine (500, 1000 and 2000 mg/kg), for 9 continuous days. To assess antinociceptive effect of morphine, percentage of maximal possible effect (%MPE) of animals exposed to thermal stimulus was measured in the hot plate test, 30 min after morphine administration. Test was performed on days 1, 3, 5, 7 and 9. The effect of glucosamine on the naloxone (5 mg/kg, i.p.)-precipitated morphine withdrawal, was also evaluated. Changes in brain gene expression levels of induced nitric oxide synthase (iNOS), enzyme responsible for nitric oxide generation, as well as pro-inflammatory mediator, tumor necrosis alpha (TNF-α) were measured in morphine tolerated animals, as well as after withdrawal by real-time polymerase chain reaction (RT-PCR). Protein content of TNF-α was evaluated via ELISA assay.

RESULTS

Tolerance to antinociceptive effect of morphine was developed after 7 days of morphine treatment. The concurrent administration of glucosamine (500, 1000 and 2000 mg/kg) with morphine, significantly inhibited tolerance development, on days 7 and 9. In addition, glucosamine ameliorated the naloxone-precipitated opioid withdrawal symptoms (tremor, jumping, teeth chattering, grooming). However, diarrhea was significantly improved only with the dose of 500 mg/kg. Increased mRNA expression of iNOS as well as TNF-α mRNA expression and protein, after both morphine tolerance and withdrawal, were considerably reduced by glucosamine (1000 mg/kg) in the morphine withdrawal animals.

CONCLUSION

These data support the utility of glucosamine in attenuating both tolerance to nociceptive effects of morphine as well as withdrawal-induced behavioral profile. Anti-oxidant and anti-inflammatory effects are responsible, at least in part, for the protective effects of this drug.

Targeting redox regulation to treat substance use disorder using N‐acetylcysteine

Substance use disorder (SUD) is a chronic relapsing disorder characterized by transitioning from acute drug reward to compulsive drug use. Despite the heavy personal and societal burden of SUDs, current treatments are limited and unsatisfactory. For this reason, a deeper understanding of the mechanisms underlying addiction is required. Altered redox status, primarily due to drug-induced increases in dopamine metabolism, is a unifying feature of abused substances. In recent years, knowledge of the effects of oxidative stress in the nervous system has evolved from strictly neurotoxic to include a more nuanced role in redox-sensitive signaling. More specifically, S-glutathionylation, a redox-sensitive post-translational modification, has been suggested to influence the response to drugs of abuse. In this review we will examine the evidence for redox-mediating drugs as therapeutic tools focusing on N-acetylcysteine as a treatment for cocaine addiction. We will conclude by suggesting future research directions that may further advance this field.

Biochemical, Oxidative, and Physiological Changes Caused by Acute Exposure of Fentanyl and Its 3 Analogs in Rodents

Synthesis and bioefficacy of fentanyl and its 8 new 1-substituted analogs (1-8) were earlier reported by us. Of these 8 compounds, N-(1-(2-phenoxyethyl)-4-piperidinyl)propionanilide (2), N-isopropyl-3-(4-( N-phenylpropionamido)piperidin-1-yl)propanamide (5), and N- t-butyl-3-(4-( N-phenylpropionamido)piperidin-1-yl) propanamide (6) were found to be more effective and less toxic compared to fentanyl. The present study reports the acute effect of fentanyl (0.50 Median Lethal Dose (LD₅₀); intraperitoneal) and its 3 analogs (2, 5, and 6) on various biochemical and oxidative parameters in mice and various physiological parameters in rats. Blood alkaline phosphatase (1 hour and 7 days) and urea levels (1 hour) were significantly elevated by fentanyl, while alanine aminotransferase levels (1 hour) were increased by both fentanyl and analog 2 compared to the corresponding control. Increase in partial pressure of carbon dioxide and decrease in partial pressure of oxygen were also caused by fentanyl and analog 2 (1 hour). Analog 6 alone elevated malondialdehyde levels in the brain, liver, and kidney tissues (7 days). The LD₅₀ of fentanyl and analogs 2, 5, and 6 were found to be 0.879, 87.88, 69.80, and 55.44 mg/kg, respectively, in rats. Significant decrease in heart rate, mean arterial pressure, respiratory rate (RR), and neuromuscular transmission was produced by fentanyl and analog 2, while analog 5 decreased the RR alone. The changes, particularly the respiratory depression, were found to be reversed by naloxone, a μ-receptor antagonist. Thereby, indicating involvement of μ-receptor mediated effects of the compounds. To conclude, all the analogs were found to be less toxic compared to fentanyl, suggesting their possible role in pain management.

MnSOD mediated by HSV vectors in the periaqueductal gray suppresses morphine withdrawal in rats

Morphine appears to be the most active metabolite of heroin; therefore, the effects of morphine are important in understanding the ramifications of heroin abuse. Opioid physical dependence (withdrawal response) may have very long-lasting effects on the motivation for reward, including the incubation of cue-induced drug-seeking behavior. However, the exact mechanisms of morphine withdrawal (MW) are not clear yet, and its treatment remains elusive. Periaqueductal gray (PAG) is one of the important sites in the pathogenesis of MW. Here, we used recombinant herpes simplex virus (HSV) vectors that encode the sod2 gene expressing manganese superoxide dismutase (MnSOD) to evaluate its therapeutic potential in MW. Microinjection of HSV vectors expressing MnSOD into the PAG reduced the MW syndrome. MnSOD vectors suppressed the upregulated mitochondrial superoxide, and endoplasmic reticulum stress markers (glucose-related protein 78 (GRP78) and activating transcription factor 6 alpha (ATF6α)) in the PAG induced by MW. Immunostaining showed that mitochondrial superoxide, GRP78 and ATF6α were colocalized with neuronal nuclei (a neuronal-specific marker), suggesting that they are located in the neurons in the PAG. These results suggest that overexpression of MnSOD by HSV vectors may relieve opioid dependence. This study may provide a novel therapeutic approach to morphine physical withdrawal response.

Evaluation of Antioxidant Status, High Sensitivity C-reactive Protein, and Insulin Resistance in Male Chronic Opiate Users Without Comorbidities

BACKGROUND

There is a paucity of data on frequency of metabolic syndrome (MS), insulin resistance (IR), and oxidative stress in Indian opiate users without comorbidities.

OBJECTIVES

To determine the influence of opiate use on frequency of MS, homeostasis model assessment for IR (HOMA-IR), high-sensitivity C-reactive protein (hs-CRP), and oxidative stress in opiate-dependent male patients without comorbidities.

METHODS

Participants (n = 120) were grouped as controls (Group I), pure opiate dependents (Group II), opiate + tobacco dependents (Group III), and tobacco dependents (Group IV) with a minimum of 1-year dependence participated in the study. Participants were evaluated for anthropometric parameters, blood pressure (BP), fasting blood sugar, insulin, HOMA-IR, lipid profile, hs-CRP, and total antioxidant status (TAS). Frequency of MS was determined based on modified Adult Treatment Panel-III. The data were analyzed using one-way ANOVA, multiple regression by SPSS 21.

RESULTS

Frequency of MS in opiate dependents was higher than control. There was a significant difference in serum insulin, HOMA-IR, and TAS levels of the study groups. Multiple regression analysis showed dependence years, body mass index, waist-hip ratio, systolic blood pressure, diastolic blood pressure (DBP), HOMA-IR, and hs-CRP to be significant independent predictors of TAS in Group II and III patients with MS after adjusting for age and education years. TAS and DBP significantly predicted hs-CRP after adjusting for age and education years in Group II and III patients with MS. No such relation was seen in Group I and IV.

CONCLUSIONS

Chronic opiate-dependent males without comorbidity are a unique group that shows low-grade inflammation, oxidative stress, and prevalence of MS predisposing them to future risk of cardiovascular diseases.

Acquisition, Maintenance and Relapse-Like Alcohol Drinking: Lessons from the UChB Rat Line

This review article addresses the biological factors that influence: (i) the acquisition of alcohol intake; (ii) the maintenance of chronic alcohol intake; and (iii) alcohol relapse-like drinking behavior in animals bred for their high-ethanol intake. Data from several rat strains/lines strongly suggest that catalase-mediated brain oxidation of ethanol into acetaldehyde is an absolute requirement (up 80%–95%) for rats to display ethanol’s reinforcing effects and to initiate chronic ethanol intake. Acetaldehyde binds non-enzymatically to dopamine forming salsolinol, a compound that is self-administered. In UChB rats, salsolinol: (a) generates marked sensitization to the motivational effects of ethanol; and (b) strongly promotes binge-like drinking. The specificity of salsolinol actions is shown by the finding that only the R-salsolinol enantiomer but not S-salsolinol accounted for the latter effects. Inhibition of brain acetaldehyde synthesis does not influence the maintenance of chronic ethanol intake. However, a prolonged ethanol withdrawal partly returns the requirement for acetaldehyde synthesis/levels both on chronic ethanol intake and on alcohol relapse-like drinking. Chronic ethanol intake, involving the action of lipopolysaccharide diffusing from the gut, and likely oxygen radical generated upon catechol/salsolinol oxidation, leads to oxidative stress and neuro-inflammation, known to potentiate each other. Data show that the administration of N-acetyl cysteine (NAC) a strong antioxidant inhibits chronic ethanol maintenance by 60%–70%, without inhibiting its initial intake. Intra-cerebroventricular administration of mesenchymal stem cells (MSCs), known to release anti-inflammatory cytokines, to elevate superoxide dismutase levels and to reverse ethanol-induced hippocampal injury and cognitive deficits, also inhibited chronic ethanol maintenance; further, relapse-like ethanol drinking was inhibited up to 85% for 40 days following intracerebral stem cell administration. Thus: (i) ethanol must be metabolized intracerebrally into acetaldehyde, and further into salsolinol, which appear responsible for promoting the acquisition of the early reinforcing effects of ethanol; (ii) acetaldehyde is not responsible for the maintenance of chronic ethanol intake, while other mechanisms are indicated; (iii) the systemic administration of NAC, a strong antioxidant markedly inhibits the maintenance of chronic ethanol intake; and (iv) the intra-cerebroventricular administration of anti-inflammatory and antioxidant MSCs inhibit both the maintenance of chronic ethanol intake and relapse-like drinking.

Neonatal Abstinence Syndrome and High School Performance

BACKGROUND AND OBJECTIVES

Little is known of the long-term, including school, outcomes of children diagnosed with Neonatal abstinence syndrome (NAS) (International Statistical Classification of Disease and Related Problems [10th Edition], Australian Modification, P96.1).

METHODS

Linked analysis of health and curriculum-based test data for all children born in the state of New South Wales (NSW), Australia, between 2000 and 2006. Children with NAS (n = 2234) were compared with a control group matched for gestation, socioeconomic status, and gender (n = 4330, control) and with other NSW children (n = 598 265, population) for results on the National Assessment Program: Literacy and Numeracy, in grades 3, 5, and 7.

RESULTS

Mean test scores (range 0-1000) for children with NAS were significantly lower in grade 3 (359 vs control: 410 vs population: 421). The deficit was progressive. By grade 7, children with NAS scored lower than other children in grade 5. The risk of not meeting minimum standards was independently associated with NAS (adjusted odds ratio [aOR], 2.5; 95% confidence interval [CI], 2.2-2.7), indigenous status (aOR, 2.2; 95% CI, 2.2-2.3), male gender (aOR, 1.3; 95% CI, 1.3-1.4), and low parental education (aOR, 1.5; 95% CI, 1.1-1.6), with all Ps < .001.

CONCLUSIONS

A neonatal diagnostic code of NAS is strongly associated with poor and deteriorating school performance. Parental education may decrease the risk of failure. Children with NAS and their families must be identified early and provided with support to minimize the consequences of poor educational outcomes.

Morphine Withdrawal Modifies Prion Protein Expression in Rat Hippocampus

The hippocampus is a vulnerable brain structure susceptible to damage during aging and chronic stress. Repeated exposure to opioids may alter the brain so that it functions normally when the drugs are present, thus, a prolonged withdrawal might lead to homeostatic changes headed for the restoration of the physiological state. Abuse of morphine may lead to Reacting Oxygen Species-induced neurodegeneration and apoptosis. It has been proposed that during morphine withdrawal, stress responses might be responsible, at least in part, for long-term changes of hippocampal plasticity. Since prion protein is involved in both, Reacting Oxygen Species mediated stress responses and synaptic plasticity, in this work we investigate the effect of opiate withdrawal in rats after morphine treatment. We hypothesize that stressful stimuli induced by opiate withdrawal, and the subsequent long-term homeostatic changes in hippocampal plasticity, might modulate the Prion protein expression. Our results indicate that abstinence from the opiate induced a time-dependent and region-specific modification in Prion protein content, indeed during morphine withdrawal a selective unbalance of hippocampal Prion Protein is observable. Moreover, Prion protein overexpression in hippocampal tissue seems to generate a dimeric structure of Prion protein and α-cleavage at the hydrophobic domain. Stress factors or toxic insults can induce cytosolic dimerization of Prion Protein through the hydrophobic domain, which in turn, it stimulates the α-cleavage and the production of neuroprotective Prion protein fragments. We speculate that this might be the mechanism by which stressful stimuli induced by opiate withdrawal and the subsequent long-term homeostatic changes in hippocampal plasticity, modulate the expression and the dynamics of Prion protein.

S-Glutathionylation and Redox Protein Signaling in Drug Addiction

Drug addiction is a chronic relapsing disorder that comes at a high cost to individuals and society. Therefore understanding the mechanisms by which drugs exert their effects is of prime importance. Drugs of abuse increase the production of reactive oxygen and nitrogen species resulting in oxidative stress. This change in redox homeostasis increases the conjugation of glutathione to protein cysteine residues; a process called S-glutathionylation. Although traditionally regarded as a protective mechanism against irreversible protein oxidation, accumulated evidence suggests a more nuanced role for S-glutathionylation, namely as a mediator in redox-sensitive protein signaling. The reversible modification of protein thiols leading to alteration in function under different physiologic/pathologic conditions provides a mechanism whereby change in redox status can be translated into a functional response. As such, S-glutathionylation represents an understudied means of post-translational protein modification that may be important in the mechanisms underlying drug addiction. This review will discuss the evidence for S-glutathionylation as a redox-sensing mechanism and how this may be involved in the response to drug-induced oxidative stress. The function of S-glutathionylated proteins involved in neurotransmission, dendritic spine structure, and drug-induced behavioral outputs will be reviewed with specific reference to alcohol, cocaine, and heroin.

Drug-induced neurotoxicity in addiction medicine: From prevention to harm reduction

Neurotoxicity is considered as a major cause of neurodegenerative disorders. Most drugs of abuse have nonnegligible neurotoxic effects many of which are primarily mediated by several dopaminergic and glutamatergic neurotransmitter systems. Although many researchers have investigated the medical and cognitive consequences of drug abuse, the neurotoxicity induced by these drugs still requires comprehensive attention. The science of neurotoxicity promises to improve preventive and therapeutic strategies for brain disorders such as Alzheimer disease and Parkinson's disease. However, its clinical applications for addiction medicine remain to be defined adequately. This chapter reviews the most commonly discussed mechanisms underlying neurotoxicity induced by common drugs of abuse including amphetamines, cocaine, opiates, and alcohol. In addition, the known factors that trigger and/or predispose to drug-induced neurotoxicity are discussed. These factors include drug-related, individual-related, and environmental insults. Moreover, we introduce some of the potential pharmacological antineurotoxic interventions deduced from experimental animal studies. These interventions involve various targets such as dopaminergic system, mitochondria, cell death signaling, and NMDA receptors, among others. We conclude the chapter with a discussion of addicted patients who might benefit from such interventions.

Chronic oxycodone induces integrated stress response in rat brain

BACKGROUND

Oxycodone is an opioid that is prescribed to treat multiple types of pain, especially when other opioids are ineffective. Unfortunately, similar to other opioids, repetitive oxycodone administration has the potential to lead to development of analgesic tolerance, withdrawal, and addiction. Studies demonstrate that chronic opioid exposure, including oxycodone, alters gene expression profiles and that these changes contribute to opioid-induced analgesic effect, tolerance and dependence. However, very little is known about opioids altering the translational machinery of the central nervous system. Considering that opioids induce clinically significant levels of hypoxia, increase intracellular Ca(2+) levels, and induce the production of nitric oxide and extracellular glutamate transmission, we hypothesize that opioids also trigger a defensive mechanism called the integrated stress response (ISR). The key event in the ISR activation, regardless of the trigger, is phosphorylation of translation initiation factor 2 alpha (eIF2α), which modulates expression and translational activation of specific mRNAs important for adaptation to stress. To test this hypothesis, we used an animal model in which female rats were orally gavaged with 15 mg/kg of oxycodone every 24 h for 30 days.

RESULTS

We demonstrated increased levels of hsp70 and BiP expression as well as phosphorylation of eIF2α in various rat brain areas after oxycodone administration. Polysomal analysis indicated oxycodone-induced translational stimulation of ATF4 and PDGFRα mRNAs, which have previously been shown to depend on the eIF2α kinase activation. Moreover, using breast adenocarcinoma MCF7 cells, which are known to express the μ-opioid receptor, we observed induction of the ISR pathway after one 24-h treatment with oxycodone.

CONCLUSIONS

The combined in vivo and in vitro data suggest that prolonged opioid treatment induces the integrated stress response in the central nervous system; it modulates translational machinery in favor of specific mRNA and this may contribute to the drug-induced changes in neuronal plasticity.

Redox-based epigenetic status in drug addiction: a potential contributor to gene priming and a mechanistic rationale for metabolic intervention

Alcohol and other drugs of abuse, including psychostimulants and opioids, can induce epigenetic changes: a contributing factor for drug addiction, tolerance, and associated withdrawal symptoms. DNA methylation is a major epigenetic mechanism and it is one of more than 200 methylation reactions supported by methyl donor S-adenosylmethionine (SAM). Levels of SAM are controlled by cellular redox status via the folate and vitamin B12-dependent enzyme methionine synthase (MS). For example, under oxidative conditions MS is inhibited, diverting its substrate homocysteine (HCY) to the trans sulfuration pathway. Alcohol, dopamine, and morphine, can alter intracellular levels of glutathione (GSH)-based cellular redox status, subsequently affecting SAM levels and DNA methylation status. Here, existing evidence is presented in a coherent manner to propose a novel hypothesis implicating the involvement of redox-based epigenetic changes in drug addiction. Further, we discuss how a “gene priming” phenomenon can contribute to the maintenance of redox and methylation status homeostasis under various stimuli including drugs of abuse. Additionally, a new mechanistic rationale for the use of metabolic interventions/redox-replenishers as symptomatic treatment of alcohol and other drug addiction and associated withdrawal symptoms is also provided. Hence, the current review article strengthens the hypothesis that neuronal metabolism has a critical bidirectional coupling with epigenetic changes in drug addiction exemplified by the link between redox-based metabolic changes and resultant epigenetic consequences under the effect of drugs of abuse.

Do maternal opioids reduce neonatal regional brain volumes? A pilot study

OBJECTIVE

A substantial number of children exposed to gestational opioids have neurodevelopmental, behavioral and cognitive problems. Opioids are not neuroteratogens but whether they affect the developing brain in more subtle ways (for example, volume loss) is unclear. We aimed to determine the feasibility of using magnetic resonance imaging (MRI) to assess volumetric changes in healthy opioid-exposed infants.

STUDY DESIGN

Observational pilot cohort study conducted in two maternity hospitals in New South Wales, Australia. Maternal history and neonatal urine and meconium screens were obtained to confirm drug exposure. Volumetric analysis of MRI scans was performed with the ITK-snap program.

RESULT

Scans for 16 infants (mean (s.d.) gestational age: 40.9 (1.5) weeks, birth weight: 3022.5 (476.6) g, head circumference (HC): 33.7 (1.5 cm)) were analyzed. Six (37.5%) infants had HC <25th percentile. Fourteen mothers used methadone, four used buprenorphine and 11 used more than one opioid (including heroin, seven). All scans were structurally normal whole brain volumes (357.4 (63.8)) and basal ganglia (14.5 (3.5)) ml were significantly smaller than population means (425.4 (4.8), 17.1 (4.4) ml, respectively) but lateral ventricular volumes (3.5 (1.8) ml) were larger than population values (2.1(1.5)) ml.

CONCLUSION

Our pilot study suggests that brain volumes of opioid-exposed babies may be smaller than population means and that specific regions, for example, basal ganglia, that are involved in neurotransmission, may be particularly affected. Larger studies including correlation with neurodevelopmental outcomes are warranted to substantiate this finding.

Hypoxia/ischemia a key player in early post stroke seizures: modulation by opioidergic and nitrergic systems

Stroke is a leading cause of death, disability, and socioeconomic loss worldwide. All attempts at pharmacological reduction of the complications of stroke (e.g. post-stroke seizure, and brain׳s vulnerability to hypoxic/ischemic injury) have failed. Endogenous opioids and nitric oxide (NO) overproduction has been documented in brain hypoxia/ischemia (H/I), which can exert pro-convulsive effects. In this study, we aimed to examine the possible involvement of opioidergic and nitrergic pathways in the pathogenesis of post-stroke seizure. H/I was induced by right common carotid ligation and sham-operated mice served as controls. We demonstrated that right common carotid ligation decreases the threshold for clonic seizures induced by pentylenetetrazole (PTZ), a GABA antagonist. Furthermore, pro-convulsive effect of H/I following right common carotid ligation was blocked by naltrexone (NTX) (3mg/kg), NG-Nitro-l-arginine methyl ester (l-NAME) (10mg/kg), and aminoguanidine (AG) (100mg/kg) administration (P<0.001). Interestingly, co-administration of non-effective doses of NTX and l-NAME (1 and 0.5mg/kg, respectively) reverses epileptogenesis of H/I (P<0.001). In the same way, co-administration of non-effective doses of NTX and AG (1 and 5mg/kg, respectively), reverses epileptogenesis of H/I (P<0.001). Indeed, the histological studies performed on mice exposed to H/I confirmed our previous data. These findings suggest hyper-susceptibility to PTZ induced seizure following H/I is mediated by interaction of opioidergic, and iNOS/NO pathways. Therefore, our results identify new pharmacological targets and provide the rationale for a novel strategy to promote recovery after stroke and possibly other brain injuries.

Morphine induces redox-based changes in global DNA methylation and retrotransposon transcription by inhibition of excitatory amino acid transporter type 3-mediated cysteine uptake

Canonically, opioids influence cells by binding to a G protein-coupled opioid receptor, initiating intracellular signaling cascades, such as protein kinase, phosphatidylinositol 3-kinase, and extracellular receptor kinase pathways. This results in several downstream effects, including decreased levels of the reduced form of glutathione (GSH) and elevated oxidative stress, as well as epigenetic changes, especially in retrotransposons and heterochromatin, although the mechanism and consequences of these actions are unclear. We characterized the acute and long-term influence of morphine on redox and methylation status (including DNA methylation levels) in cultured neuronal SH-SY5Y cells. Acting via μ-opioid receptors, morphine inhibits excitatory amino acid transporter type 3-mediated cysteine uptake via multiple signaling pathways, involving different G proteins and protein kinases in a temporal manner. Decreased cysteine uptake was associated with decreases in both the redox and methylation status of neuronal cells, as defined by the ratios of GSH to oxidized forms of glutathione and S-adenosylmethionine to S-adenosylhomocysteine levels, respectively. Further, morphine induced global DNA methylation changes, including CpG sites in long interspersed nuclear elements (LINE-1) retrotransposons, resulting in increased LINE-1 mRNA. Together, these findings illuminate the mechanism by which morphine, and potentially other opioids, can influence neuronal-cell redox and methylation status including DNA methylation. Since epigenetic changes are implicated in drug addiction and tolerance phenomenon, this study could potentially extrapolate to elucidate a novel mechanism of action for other drugs of abuse.

Molecular Advances Leading to Treatment Implications for Fragile X Premutation Carriers

Fragile X syndrome (FXS) is the most common single gene cause of intellectual disability and it is characterized by a CGG expansion of more than 200 repeats in the FMR1 gene, leading to methylation of the promoter and gene silencing. The fragile X premutation, characterized by a 55 to 200 CGG repeat expansion, causes health problems and developmental difficulties in some, but not all, carriers. The premutation causes primary ovarian insufficiency in approximately 20% of females, psychiatric problems (including depression and/or anxiety) in approximately 50% of carriers and a neurodegenerative disorder, the fragile X-associated tremor ataxia syndrome (FXTAS), in approximately 40% of males and 16% of females later in life. Recent clinical studies in premutation carriers have expanded the health problems that may be seen. Advances in the molecular pathogenesis of the premutation have shown significant mitochondrial dysfunction and oxidative stress in neurons which may be amenable to treatment. Here we review the clinical problems of carriers and treatment recommendations.

Protective Effect of Bacoside-A against Morphine-Induced Oxidative Stress in Rats

In the present study, we investigated the protective effect of bacoside-A the active principle isolated from the plant Bacopa monniera against oxidative damage induced by morphine in rat brain. Morphine intoxicated rats received 10-160 mg/kg b.w. of morphine hydrochloride intraperitoneally for 21 days. Bacoside-A pretreated rats were administered with bacoside-A (10 mg/kg b.w/day) orally, 2 h before the injection of morphine for 21 days. Pretreatment with bacoside-A has shown to possess a significant protective role against morphine induced brain oxidative damage in the antioxidant status (total reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase and lipid peroxidation) and membrane bound ATP-ases(Na⁺/K⁺ATPase. Ca²⁺ and Mg²⁺ ATPases) activities in rat. The results of the present study indicate that bacoside-A protects the brain from oxidative stress induced by morphine.

Enhancement of μ-opioid receptor desensitization by nitric oxide in rat locus coeruleus neurons: involvement of reactive oxygen species

It has previously been shown that nitric oxide (NO) synthase is involved in the development of opioid tolerance. The aim of the present work was to study the effect of NO on μ-opioid receptor (MOR) desensitization. Furthermore, we explored the possible role of reactive oxygen species (ROS) in this effect. Single-unit extracellular and whole-cell patch-clamp recordings were performed on locus coeruleus (LC) neurons from rat brain slices. Perfusion with high concentrations of Met(5)-enkephalin (ME) caused a concentration-related reduction of opioid effect, reflecting the induction of homologous MOR desensitization. The NO donors sodium nitroprusside and diethylamine NONOate markedly enhanced the ME-induced MOR desensitization, although the acute effect of ME on K(+) conductance was not affected by sodium nitroprusside. Continuous perfusion with the antioxidants melatonin, trolox, 21-[4-(2,6-di-1-pyrrolidinyl-4-pyrrimidinyl)-1-piperazinyl]-pregna-1,4,9(11)-triene-3,20-dione(Z)-2-butenedioate (U74389G), and diethyldithiocarbamate prevented the effect of sodium nitroprusside on MOR desensitization, but they did not themselves alter the desensitization. Like sodium nitroprusside, the ROS-generating molecule H(2)O(2) enhanced MOR desensitization induced by ME. However, α(2)-adrenoceptor desensitization induced by noradrenaline was not modified by H(2)O(2), suggesting a selective action of ROS on MOR. Our results suggest that elevated levels of NO, which may be reached in pathological processes, enhance homologous desensitization of MOR in the LC, probably through a mechanism involving ROS generation.