The effect of morphine administration on GluN3B NMDA receptor subunit mRNA expression in rat brain.

Opioid addiction is critically dependent on the activation of N­methyl­D­aspartate (NMDA) receptors, which are widely found in the mesocorticolimbic system. Meanwhile, opioid addiction may affect the expression level of NMDA receptor subunits. The existence of GluN3 subunits in the NMDA receptor's tetramer structure reduces the excitatory current of the receptor channel. We evaluated the changes in the mRNA expression pattern of the GluN3B subunit of the NMDA receptor in rat brains following acute and chronic exposure to morphine. Chronic, escalating intraperitoneal doses of morphine or saline were administered twice daily to male Wistar rats for six days. Two other groups were injected with a single acute dose of morphine or saline. The mRNA level of the GluN3B subunit of the NMDA receptor in the striatum, hippocampus, and nucleus accumbens (NAc) was measured by real­time PCR. mRNA expression of the GluN3B subunit was considerably augmented (3.15 fold) in the NAc of animals chronically treated with morphine compared to the control group. The difference between rats that were chronically administered morphine and control rats was not statistically significant for other evaluated brain areas. In rats acutely treated with morphine, no significant differences were found for GluN3B subunit expression in the examined brain regions compared to the control group. It was concluded that chronic exposure to morphine notably increased the GluN3B subunit of the NMDA receptor in NAc. The extent of the impact of this finding on opioid addiction and its features requires further evaluation in future studies.

Alcohol: Epigenome alteration and inter/transgenerational effect.

While DNA serves as the fundamental genetic blueprint for an organism, it is not a static entity. Gene expression, the process by which genetic information is utilized to create functional products like proteins, can be modulated by a diverse range of environmental factors. Epigenetic mechanisms, including DNA methylation, histone modification, and microRNAs, play a pivotal role in mediating the intricate interplay between the environment and gene expression. Intriguingly, alterations in the epigenome have the potential to be inherited across generations. Alcohol use disorder (AUD) poses significant health issues worldwide. Alcohol has the capability to induce changes in the epigenome, which can be inherited by offspring, thus impacting them even in the absence of direct alcohol exposure. This review delves into the impact of alcohol on the epigenome, examining how its effects vary based on factors such as the age of exposure (adolescence or adulthood), the duration of exposure (chronic or acute), and the specific sample collected (brain, blood, or sperm). The literature underscores that alcohol exposure can elicit diverse effects on the epigenome during different life stages. Furthermore, compelling evidence from human and animal studies demonstrates that alcohol induces alterations in epigenome content, affecting both the brain and blood. Notably, rodent studies suggest that these epigenetic changes can result in lasting phenotype alterations that extend across at least two generations. In conclusion, the comprehensive literature analysis supports the notion that alcohol exposure induces lasting epigenetic alterations, influencing the behavior and health of future generations. This knowledge emphasizes the significance of addressing the potential transgenerational effects of alcohol and highlights the importance of preventive measures to minimize the adverse impact on offspring.

Does Morphine Exposure Before Gestation Change Anxiety-Like Behavior During Morphine Dependence in Male Wistar Rats?

Background: Anxiety is one of the comorbid disorders of opioid addiction, which leads to opioid abuse or persuades people to engage in opioid abuse. Evidence revealed that morphine exposure before conception changes the offspring's phenotype. The current study aimed to investigate the influence of morphine dependence and abstinence on anxiety-like behavior in morphine-exposed and drug-naïve offspring. Methods: Adult male and female rats were treated with morphine or vehicle for 21 days. Then, all rats were left without drug treatment for 10 days. A morphine-exposed female rat was mated with either a vehicle-exposed or morphine-abstinent male. According to parental morphine exposure, the offspring were categorized into four distinct groups: (1) control (both drug-naïve parents), (2) paternal morphine-exposed, (3) maternal morphine-exposed, and (4) biparental morphine-exposed. The anxiety-like behavior was measured in adult male offspring using open field and elevated plus-maze tests before morphine exposure (naïve), 21 days after morphine exposure (dependence), and ten days after the last morphine exposure (abstinence). Findings: The results indicated that anxiety-like behavior increased before morphine exposure in maternal and biparental morphine-exposed offspring (P<0.05). However, after morphine exposure, the anxiety level did not change among the groups. Ten days after the last morphine exposure, anxiety-like behavior increased only in biparental morphine-exposed offspring (P<0.05). Conclusion: The offspring of morphine-abstinent parents exhibited an anxious phenotype. Disruption of the HPA axis was seen in the progeny of maternal and biparental morphine-exposed rats. Indeed, morphine exposure for 21 days did not change anxiety-like behavior in these offspring which might be correlated to disruption of HPA axis in them.

The role of lateral habenula NMDA receptors in tramadol-induced conditioning.

The role of the lateral habenula (LHb) as a hub for receiving and relaying signals from the limbic system to serotonergic, dopaminergic, and norepinephrinergic regions in the brainstem makes this area a critical region in the control of reward and addiction. Behavioral evidence reveals the vital role of the LHb in negative symptoms during withdrawal. In this investigation, we study the role of the LHb N-Methyl D-Aspartate receptor (NMDAR) in the modulation of tramadol reward. Male adult Wistar rats were used in this study. The effect of intra-LHb micro-injection of NMDAR agonist (NMDA, 0.1, 0.5, 2 µg/rat) and antagonist (D-AP5, 0.1, 0.5, 1 µg/rat) was evaluated in conditioned place preference (CPP) paradigm. The obtained results showed that intra-LHb administration of NMDA induced place aversion dose-dependently, while blockade of NMDAR in the LHb using D-AP5 micro-injection led to an increased preference score in the CPP task. Co-administration of NMDA (0.5 µg/rat) with tramadol (4 mg/kg) reduced preference score, while co-administration of D-AP5 (0.5 µg/rat) with a non-effective dose of tramadol (1 mg/kg) potentiate the rewarding effect of tramadol. LHb receives inputs from the limbic system and projects to the monoaminergic nuclei in the brainstem. It has been declared that NMDAR is expressed in LHb, and as obtained data revealed, these receptors could modulate the rewarding effect of tramadol. Therefore, NMDA receptors in the LHb might be a new target for modulating tramadol abuse.

Inter/Transgenerational Effects of Drugs of Abuse: A Scoping Review.

Drug addiction is a chronic relapsing disorder that makes it a global problem. Genetics and environmental factors are the two most important factors that make someone vulnerable to drug addiction. Investigations in the past decade highlighted the role of epigenetics in the inter/transgenerational inheritance of drug addiction. A growing body of evidence showed that parental (paternal, maternal, and biparental) drug exposure before conception changes the phenotype of the offspring, which is correlated with neurochemical and neurostructural changes in the brain. The current paper reviews the effects of parental (maternal, paternal, and biparental) exposure to drugs of abuse (opioids, cocaine, nicotine, alcohol, and cannabis) before gestation in animal models.

Effect of tramadol on apoptosis and synaptogenesis in hippocampal neurons: The possible role of µ-opioid receptor.

Tramadol is a synthetic opioid with centrally acting analgesic activity that alleviates moderate to severe pain and treats withdrawal symptoms of the other opioids. Like other opioid drugs, tramadol abuse has adverse effects on central nervous system components. Chronic administration of tramadol induces maladaptive plasticity in brain structures responsible for cognitive function, such as the hippocampus. However, the mechanisms by which tramadol induces these alternations are not entirely understood. Here, we examine the effect of tramadol on apoptosis and synaptogenesis of hippocampal neuronal in vitro. First, the primary culture of hippocampal neurons from neonatal rats was established, and the purity of the neuronal cells was verified by immunofluorescent staining. To evaluate the effect of tramadol on neuronal cell viability MTT assay was carried out. The western blot analysis technique was performed for the assessment of apoptosis and synaptogenesis markers. Results show that chronic exposure to tramadol reduces cell viability of neuronal cells and naloxone reverses this effect. Also, the level of caspase-3 significantly increased in tramadol-exposed hippocampal neurons. Moreover, tramadol downregulates protein levels of synaptophysin and stathmin as synaptogenesis markers. Interestingly, the effects of tramadol were abrogated by naloxone treatment. These findings suggest that tramadol can induce neurotoxicity in hippocampal neuronal cells, and this effect was partly mediated through opioid receptors.

Exercise can restore behavioural and molecular changes of intergenerational morphine effects.

In our previous studies, the offspring of morphine-exposed parents (MEO) showed pharmacological tolerance to the morphine's reinforcing effect. According to the role of exercise in treatment of morphine addiction, the current study was designed to utilize exercise to improve the effect of parental morphine exposure on the morphine's reinforcing effect. Male and female rats received morphine for 10 days and were drug-free for another 10 days. Each morphine-exposed animal was allowed to mate either with a drug-naïve or a morphine-exposed rat. The offspring were divided into two groups: (1) offspring that were subjected to treadmill exercise and (2) offspring that were not subjected to exercise. The reinforcing effect of morphine was evaluated using conditioned place preference (CPP) and two-bottle choice (TBC) tests. Levels of dopamine receptors (D1DR and D2DR), µ-opioid receptor (MOR), and ΔFosB were evaluated in the nucleus accumbens. The MEO obtained lower preference scores in CPP and consumed morphine more than the control group in TBC. After 3 weeks of exercise, the reinforcing effect of morphine in the MEO was similar to the control. D1DR, D2DR, and MOR were increased in MEO compared with the controls before exercise. Levels of D1DR and MOR were decreased after exercise in the MEO; however, D1DR was increased in control. D2DR level did not change after exercise in MEO, but it increased in control group. Moreover, the level of ΔFosB was decreased among MEO while it was increased after exercise. In conclusion, exercise might modulate the reinforcing effect of morphine via alteration in levels of D1DR, MOR, and ΔFosB.

Tannic acid protects aged brain against cerebral hypoperfusion via modulation of Nrf2 and inflammatory pathways.

Current study purposed to investigate the neuroprotective effects of Tannic Acid (TA) on mild chronic cerebral hypoperfusion model in rats. Male Wistar rats were subjected to permanent Unilateral Common Carotid Artery Occlusion (UCCAO), followed by TA treatment (0.05% w/v) in drinking water for one month. Nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H: quinone oxidoreductase 1 (NQO-1), heme oxygenase-1 (HO-1), factor kappa-light-chain-enhancer of activated B cells (NF-κB), tumor necrosis factor-α (TNF-α), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), caspase-3, blood triglyceride, blood glucose, and liver enzymes' activity were detected after the experimental period. Also, behavioral tests, hematoxylin and eosin (H&E) staining, and PET scan were performed after treatment. Post-treatment of TA improved locomotion and memory function (P < 0.001), and reduced neural cell death (P < 0.001) in the treatment group compared to UCCAO rats. Furthermore, long-term TA treatment significantly increased the levels of Nrf2 (P < 0.001), NQO-1 (P < 0.001), and HO-1 (P < 0.001) in the hippocampus of the treatment group compared to the UCCAO group. TA consumption in the treatment group applied its anti-inflammatory effects via reducing the activity of NF-κB and TNF-α in comparison with the UCCAO group (P < 0.001 for both). Blood triglyceride, blood glucose, and liver enzymes did not change considerably in the groups (P > 0.05). The current results indicate that long-term post-treatment of TA exhibits protective effects against memory deficit and motor dysfunction. The cellular mechanism of TA in hypoperfused rats might be associated with the activation of antioxidant pathways, especially the Nrf2 pathway, and suppressing inflammatory factors like NF-κB and TNF-α.

Effects of Morphine and Maternal Care on Behaviors and Protein Expression of Male Offspring.

Genes and environment interact during development to alter gene expression and behavior. Parental morphine exposure before conception has devastating effects on the offspring. In the present study, we evaluated the role of maternal care in the intergenerational effect of maternal morphine exposure. Female rats received morphine or saline for ten days and were drugfree for another ten days. Thereafter, they were allowed to mate with drug-naïve male rats. When pups were born, they were cross-fostered to assess the contribution of maternal care versus morphine effects on the offspring. Adult male offspring were examined for anxiety-like behavior, spatial memory, and obsessive-compulsive-like behavior. To determine the mechanisms underlying the observed behavioral changes, protein levels of acetylated histone H3, BDNF, Trk-B, NMDA subunits, p-CREB, and 5-HT3R were measured in the brain. Our results indicate that maternal caregiving is impaired in morphine-abstinent mothers. Interestingly, maternal care behaviors were also affected in drug-naïve mothers that raised offspring of morphine-exposed mothers. In addition, the offspring of morphine abstinent and non-drug dependent mothers, when raised by morphine abstinent mothers, exhibited more anxiety, obsessive-compulsive behaviors and impaired spatial memory. These altered behaviors were associated with alterations in the levels of the above-mentioned proteins. These data illustrate the intergenerational effects of maternal morphine exposure on offspring behaviors. Moreover, exposure to morphine before gestation not only affects maternal care and offspring behavior, but also has negative consequences on behaviors and protein expression in adoptive mothers of affected offspring.

Comparison and interaction of morphine and CB1 agonist conditioned place preference in the rat model of early life stress.

Early life stress (ELS) disrupts brain development and subsequently affects physical and psychological health. ELS has been associated with an increased risk of relapse and inadequate treatment response in addicted patients. The current study was designed to find the effect of ELS on the rewarding effect of morphine and cannabinoid and their interaction. Pregnant female Wistar rats were used in this study. On postnatal day 2 (PND2), pups were separated from their mothers for 3 hr daily. This procedure was repeated every day at the same time until PND 14. The control group was kept in the standard nesting way with their mothers. The adult male offspring of maternal separated (MS) and standard nested (SN) rats were used. Using conditioned place preference task (CPP), the rewarding effect of morphine (0.75, 1.25, 2.5, and 5 mg/kg) was evaluated in both MS and SN groups. Besides, the rewarding effect of cannabinoids was investigated using the administration of CB1 receptor agonist (ACPA, 0.25, 0.5, 1 µg/rat) and inverse agonist (AM-251, 30, 60, and 90 ng/rat) in the nucleus accumbens (NAc). To evaluate the interaction between NAc cannabinoidergic system and morphine, the noneffective dose of ACPA and AM-251 were administered with a noneffective dose of morphine (0.75 mg/kg) on both MS and SN animals. Obtained results indicated that MS groups had a leftward shift in the rewarding effect of morphine and conditioned with low doses of morphine. However, they had a rightward shift in the rewarding effect of cannabinoids. In addition, coadministration of noneffective doses of morphine and ACPA potentiate conditioning in both MS and SN groups. Previous evidence shows that ELS induced changes in the brain, especially in the reward circuits. Here, we demonstrated that MS animals are more sensitive to the rewarding effect of morphine compared with SN animals. In addition, ELS disrupts the cannabinoid system and affect the rewarding effect of cannabinoids.

Tramadol Treatment Induces Change in Phospho-Cyclic Adenosine Monophosphate Response Element-Binding Protein and Delta and Mu Opioid Receptors within Hippocampus and Amygdala Areas of Rat Brain.

BACKGROUND: Tramadol induces its unique effects through opioid pathways, but the exact mechanism is not known. The study aims to evaluate changes in the level of mu-opioid receptor (µOR), delta-opioid receptor (δOR), and phosphorylated cyclic adenosine monophosphate (cAMP) response element-binding protein (p-CREB) in the hippocampus (HPC) and amygdala (AL) areas of tramadol-treated rats. METHODS: For this purpose, a total of 36 male rats were divided into two main groups for chronic or acute tramadol exposure. The animals were then exposed to 5 mg.kg-1 of tramadol, 10 mg.kg-1 of tramadol, and normal saline. The HPC and AL areas of the animals were dissected upon completion of the period. The levels of p-CREB and µOR were quantified using the western blotting technique. The data were subjected to analysis of variance (ANOVA) followed by Tukey's post-hoc analysis. The differences with the P-value lower than 0.05 were considered as significant. FINDINGS: In the HPC and AL areas of the brain, the level of µOR was decreased by acute tramadol exposure, while no significant difference was observed by chronic tramadol exposure. Moreover, results showed that the level of p-CREB dose-dependently increased by acute and chronic tramadol exposure. CONCLUSION: HPC and AL are essential in the control of tramadol abuse. Tramadol abuse affects gene expression and transcription factors such as CREB. With acute drug tramadol treatments, the level of cAMP response element-binding protein (CREB) rapidly increases, while by chronic tramadol treatment, "peak and trough pattern is observing". The activation of the rewarding mechanism is a precise instance of addictive behavior in tramadol-treated individuals.

Altered D2 receptor and transcription factor EB expression in offspring of aggressive male rats, along with having depressive and anxiety-like behaviors.

MATERIALS AND METHODS: In this study we have evaluated the behavioral mood variations, and expression of DR-D2 and TFEB genes in the amygdala and PFC of aggressive male rats' offspring. RESULTS: Anxiety and depression-like behaviors were observed, but intra-ventricle injection of DR-D2 antagonist (Sulpiride) has shown to be efficient in reducing negative behavioral changes in offspring. Furthermore, DR-D2 gene expression was increased in the amygdala and PFC of aggressive male rats' offspring, which the injection of Sulpiride decreased it significantly. TFEB gene expression was also decreased in the amygdala and PFC of aggressive male rats' offspring, but the blockade of DR-D2 had no effect on it. CONCLUSIONS: The current data suggests the possible influence of dopaminergic receptors D2 and TFEB genes on the behavioral changes which is modified by having an aggressive father.

The role of cannabinoid 1 receptor in the nucleus accumbens on tramadol induced conditioning and reinstatement.

AIMS: Previous investigations demonstrated that tramadol, as a painkiller, similar to morphine induces tolerance and dependence. Furthermore, the cannabinoid receptor 1 (CB1R) located in the nucleus accumbens (NAc) plays a critical role in morphine-induced conditioning. Therefore, the main objective of this study was to evaluate the role of NAc CB1R in tramadol induced conditioning and reinstatement. MAIN METHODS: In the present experiment, the effect of NAc CB1 receptors on tramadol induced conditioning was tested by microinjecting of arachidonylcyclopropylamide (ACPA, CB1R agonist) and AM 251 (CB1R inverse agonist) in the NAc during tramadol-induced conditioning in the adult male Wistar rats. In addition, the role of NAc CB1R in the reinstatement was also evaluated by injecting ACPA and AM 251 after a 10-days extinction period. KEY FINDINGS: The obtained data revealed that the administration of tramadol (1,2, and 4 mg/kg, ip) dose-dependently produced conditioned place preference (CPP). Moreover, intra-NAc administration of ACPA (0.25, 0.5, and 1 µg/rat) dose-dependently induced conditioning, while the administration of AM-251 (30, 60, and 120 ng/rat) induced a significant aversion. In addition, the administration of a non-effective dose of AM251 during tramadol conditioning inhibited conditioning induced by tramadol. On the other hand, the administration of ACPA after extinction induced a significant reinstatement. Notably, the locomotor activity did not change among groups. SIGNIFICANCE: Previous studies have shown that tramadol-induced CPP occurs through µ-opioid receptors. The data obtained in the current study indicated that CB1R located in the NAc is involved in mediating conditioning induced by tramadol. Besides, CB1R also plays a vital role in the reinstatement of tramadol-conditioned animals. It might be due to the effect of opioids on enhancing the level of CB1R.

Toxic effect of calcium/calmodulin kinase II on anxiety behavior, neuronal firing and plasticity in the male offspring of morphine-abstinent rats.

Studies have shown that epigenetic changes such as alteration in histone acetylation and DNA methylation in various brain regions play an essential role in anxiety behavior. According to the critical role of calcium/calmodulin protein kinaseII (CaMKII) in these processes, the present study examined the effect of CaMKII inhibitor (KN93) on neuronal activity and level of c-fos in the amygdala and nucleus accumbens (NAC) in the offspring of morphine-exposed parents. Adult male and female Wistar rats received morphine orally (for 21 days). After the washout period (10 days), rats were mated with either drug-naïve or morphine-exposed rats. KN93 was microinjected into the brain of male offspring. The anxiety-like behavior, the neuronal firing rate in the NAC and the amygdala and level of c-fos were assessed by related techniques. Data showed the offspring with one and/or two morphine-abstinent parent(s) had more anxiety-like behavior than the control group. However, the administration of KN-93 decreased anxiety in the offspring of morphine-exposed rats compared with saline-treated groups. The expression level of the c-fos was not significantly altered by the inhibition of CaMKII in the amygdala, but the c-fos level was reduced in the NAC. The neuronal firing rate of these groups was associated with an increase in the amygdala in comparison to the saline groups but was decreased in the NAC. Results showed that CaMKII had a role in anxiety-like behavior in the offspring of morphine-exposed parents, and changes in neuronal firing rate and c-fos level in the NAC might be involved in this process.

Alteration of orexin-A and PKCα in the postmortem brain of pure-opioid and multi-drug abusers.

Finding changes induced by the drug of abuse is one of the most important approaches to design new drugs for the treatment of substance use disorders (SUD). Postmortem study is the most reliable method for detecting alteration in the brain of SUD patients. Recently, the role of orexinergic system in SUD is in consideration. In the current study, we evaluated the level of orexin-A in the CSF and protein kinase Cα (PKCα) in the brain of pure-opioid (POA) and multi-drug abusers (MDA). A total of 56 POA, 45 MDA, and 13 matched control brains were collected from the legal medicine center, Tehran, Iran. The CSF was gathered from the third ventricle immediately after opening the skull and kept at -80 °C. The medial prefrontal cortex (mPFC), lateral prefrontal cortex (lPFC), orbitofrontal cortex (OFC), nucleus accumbens (NAc), and amygdala were dissected from fresh brain, frozen with liquid nitrogen and kept at -80 °C. The level of orexin-A evaluated in the CSF. Using western blotting, the level of PKCα assessed in the brain. Obtained data revealed that the level of orexin-A increased in POA and MDA compared with the control group (p < 0.05). In addition, the level of PKCα increased in the prefrontal cortex and amygdala of the abusers compared with the control group, although we did not detect changes in the level of PKCα in the NAc. Along with animal studies, the current results showed that the level of orexin increased in the CSF of drug abusers, which might be related to increases in the activation of lateral hypothalamic orexinergic neurons faced with the drug of abuse. Enhancement in the level of PKCα in the drug reward circuits might be adaptational changes induced by orexin and drugs of abuse.

Beneficial effects of physical activity on depressive and OCD-like behaviors in the male offspring of morphine-abstinent rats.

The role of parental morphine exposure before gestation on mood disorder in the offspring was well described. Besides, physical activity can improve the symptoms of mood disorders. So, the current study aimed to investigate the role of physical activity on depressive and OCD-like behaviors induced by parental morphine exposure. 40 male and 40 female Wistar rats (60-days old) received morphine for consecutive 10 days and were drug-free for 10 days. They were prepared for mating either with a morphine-abstinent or with a drug-naïve rat. The adult male offspring were divided into two groups as follows: (1) those that were subjected to treadmill exercise for three weeks (3-days each week), and (2) those without exercise. Also, the offspring were subjected to forced swimming and marble-burying tests. The levels of 5-HT3 receptor (R), D1, and D2 dopamine receptor (DR) were evaluated as well as the level of monoamine oxidase-B (MAO-B) in the prefrontal cortex (PFC). Results showed that exercise improved depressive and OCD-like behaviors in the offspring of morphine-abstinent rats. Western blotting data revealed that the levels of 5-HT3R, D1DR, D2DR, and MAO-B in the PFC increased in the offspring of morphine-abstinent rats compared to the control. However, it was shown that treadmill exercise decreases the levels of 5-HT3R, MAO-B, and D2DR. Morphine exposure, even before conception, could affect the behaviors in the offspring. Besides, the molecular changes were also detected in the brain. We found that mild physical activity might modulate OCD and depressive-like behavior in the offspring of morphine-abstinent rats by decreasing the levels of 5-HT3R, D2DR, and MAO-B located in the PFC.

Therapeutic potential of stem cells for treatment of neurodegenerative diseases.

Neurodegenerative diseases are caused by a loss of neurons within the peripheral or central nervous system. Inadequate repairability in the central nervous system and failure of treatments are the significant hurdles for several neurological diseases. The regenerative potential of stem cells drew the attention of researchers to cell-based therapy for treating neurodegenerative diseases. The clinical application of stem cells may help to substitute new cells and overcome the inability of the endogenous repairing system to repair the damaged brain. However, the clinical application induced pluripotent stem cells are restricted due to the risk of tumor formation by residual undifferentiated upon transplantation. In this focused review, we briefly discussed different stem cells currently being studied for therapeutic development. Moreover, we present supporting evidence for the utilization of stem cell therapy for the treatment of neurodegenerative diseases. Also, we described the key issues that should be considered to transplantation of stem cells for different neurodegenerative diseases. In our conclusion, stem cell therapy probably would be the only treatment strategy that offers a cure for neurodegenerative disease. Although, further study is required to identify ideal stem cells candidate, dosing and the ideal method of cell transplantation. We suggest that all grafted cells would be transgenically armed with a molecular kill-switch that could be activated by the event of adverse side effects.

Effect of morphine exposure on novel object memory of the offspring: The role of histone H3 and ΔFosB.

It has been demonstrated that alteration in histone acetylation in the regions of the brain involved in the reward which may have an important role in morphine addiction. It is well established that epigenetic changes prior to birth influence the function and development of the brain. The current study was designed to evaluate changes in novel object memory, histone acetylation and ΔFosB in the brain of the offspring of morphine-withdrawn parents. Male and female Wistar rats received morphine orally for 21 following days. After ten days of abstinent, they were prepared for mating. The male offspring of the first parturition were euthanized on postnatal days 5, 21, 30 and 60. The novel object recognition (NOR) test was performed on adult male offspring. The amount of acetylated histone H3 and ΔFosB were evaluated in the prefrontal cortex (PFC) and hippocampus using western blotting. Obtained results indicated that the discrimination index in the NOR test was decreased in the offspring of morphine-withdrawn parents as compared with morphine-naïve offspring. In addition, the level of acetylated histone H3 was decreased in the PFC and hippocampus in the offspring of morphine-withdrawn parents during lifetime (postnatal days 5, 21, 30 and 60). In the case of ΔFosB, it also decreased in these regions in the morphine-withdrawn offspring. These results demonstrated that parental morphine exposure affects NOR memory, and decreased the level of histone H3 acetylation and ΔFosB in the PFC and hippocampus. Taken together, the effect of morphine might be transmitted to the next generation even after stop consuming morphine.

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.

Activation of D1-like dopamine receptors is involved in the impairment of spatial memory in the offspring of morphine-abstinent rats.

Accumulating evidence suggests that epigenetic mechanisms play an essential role in the formation and maintenance of memory as well as addiction. In this study, we examined the role of D1-like dopamine receptor (D1 DR) on spatial memory in the offspring of morphine-abstinent rats. Adult male and female rats received morphine orally for 21 days and were drug-free for ten days. The rats were prepared to mate and the offspring were divided into four groups: offspring of drug-naïve parents, offspring of maternal morphine-exposed, offspring of paternal morphine-exposed, and PME + MME group. Saline or SCH23390 was injected into the hippocampus and prefrontal (PFC), and the Morris Water Maze task was performed. Afterward, the rats were sacrificed, and phosphorylated-CREB (p-CREB) was assessed using Western blotting. The data obtained from saline-treated offspring indicated that spatial memory was deteriorated in the offspring of morphine-abstinent parents compared with the control which improved when they received SCH23390. The level of p-CREB also decreased in the hippocampus, while it increased in the PFC and hippocampus after SCH23390 administration. Our results suggested that morphine exposure before conception could induce impairment in spatial memory in the offspring. Since D1 DR was up-regulated in the PFC of the offspring, blocking D1 DR led to improved memory deficit in the offspring of morphine-abstinent rats. Improvement of memory is correlated to p-CREB level in the hippocampus and PFC.