Trans-generational effects of parental exposure to drugs of abuse on offspring memory functions

Recent evidence reported that parental-derived phenotypes can be passed on to the next generations. Within the inheritance of epigenetic characteristics allowing the transmission of information related to the ancestral environment to the offspring, the specific case of the trans-generational effects of parental drug addiction has been extensively studied. Drug addiction is a chronic disorder resulting from complex interactions among environmental, genetic, and drug-related factors. Repeated exposures to drugs induce epigenetic changes in the reward circuitry that in turn mediate enduring changes in brain function. Addictive drugs can exert their effects trans-generally and influence the offspring of addicted parents. Although there is growing evidence that shows a wide range of behavioral, physiological, and molecular phenotypes in inter-, multi-, and trans-generational studies, transmitted phenotypes often vary widely even within similar protocols. Given the breadth of literature findings, in the present review, we restricted our investigation to learning and memory performances, as examples of the offspring's complex behavioral outcomes following parental exposure to drugs of abuse, including morphine, cocaine, cannabinoids, nicotine, heroin, and alcohol.

Balance-energy of resting state network in obsessive-compulsive disorder

Stability of the brain functional network is directly linked to organization of synchronous and anti-synchronous activities. Nevertheless, impact of arrangement of positive and negative links called links topology requires to be well understood. In this study, we investigated how topology of the functional links reduce balance-energy of the brain network in obsessive-compulsive disorder (OCD) and push the network to a more stable state as compared to healthy controls. Therefore, functional associations between the regions were measured using the phase synchrony between the EEG activities. Subsequently, balance-energy of the brain functional network was estimated based on the quality of triadic interactions. Occurrence rates of four different types of triadic interactions including weak and strong balanced, and unbalanced interactions were compared. In addition, impact of the links topology was also investigated by looking at the tendency of positive and negative links to making hubs. Our results showed although the number of positive and negative links were not statistically different between OCD and healthy controls, but positive links in OCDs' brain networks have more tendency to make hub. Moreover, lower number of unbalanced triads and higher number of strongly balanced triad reduced the balance-energy in OCDs' brain networks that conceptually has less requirement to change. We hope these findings could shed a light on better understanding of brain functional network in OCD.

Gender and age differences in suicide attempt: A large population study in the West of Iran

Present study was to evaluate the relationship between suicide attempt, gender and age. We used all of suicide attempt entered in Hamadan Suicide Registry Program (2016-2017). Finding revealed that suicide attempt was lower among elderly patients. Using poison and self-immolation was more common in elder patients. Suicide attempt in females against males was higher in married. In males the higher rate of suicide attempt was in autumn, while in females was in summer. Using of drug was more frequent in females, while self-harm was more common in males. Gender and age are important risk factors of suicide attempts.

Effect of acute and chronic restraint stress on electrical activity of prefrontal cortex neurons in the reinstatement of extinguished methamphetamine-induced conditioned place preference: An electrophysiological study

Increased vulnerability to drug abuse has been observed after exposure to stress and the prefrontal cortex (PFC) plays a major role in the control of the stress response and reward pathway. The current study was conducted to clarify the effects of acute and chronic restraint stress on PFC neural activity during the reinstatement of methamphetamine (METH)-induced conditioned place preference (CPP) in rats. Following the establishment of CPP (METH 0.5 mg/kg; s.c. for 3 days) and the extinction phase, male Wistar rats were divided into threshold (0.25 mg/kg; s.c.) and sub-threshold (0.125 mg/kg; s.c.) METH-treated super groups to induce reinstatement. Each super group contained control (non-stressed), acute restraint stress (ARS) and chronic restraint stress (CRS) groups. in vivo single unit recordings were performed on the urethane-anesthetized rats in these groups. After baseline recordings (10-min period) of the neurons in the PFC, their firing activity was recorded for 50 min during the reinstatement phase after injection of METH. The results showed that the threshold dose, but not the sub-threshold dose, of METH significantly increased PFC neural activity in the non-stressed animals. The sub-threshold dose of METH notably changed this activity in both the ARS and CRS groups. These changes in the excited neurons after the sub-threshold dose in the ARS and CRS groups were significantly higher than those in the non-stressed group. It appears that the PFC is implicated in the associated reward pathway and stress functions. METH affected the firing rate of PFC neurons and stress amplified the effect of METH on changes in the neuronal firing rate in the PFC.

Effects of Acute and Chronic Restraint Stress on Reinstatement of Extinguished Methamphetamine-induced Conditioned Place Preference in Rats

Introduction:

Methamphetamine (METH) is a neurotoxic psychostimulant with highly addictive potential that leads to compulsive drug use and vulnerability to relapse. Environmental cues, such as drug exposure, peer influence, and social stress, are the powerful triggers of drug relapse. In this study, we tried to find out the effect of acute and chronic restraint stress on reinstatement of extinguished METH-induced Conditioned Place Preference (CPP) in rats.

Methods:

Subcutaneous (SC) administration of METH (0.125, 0.25, 0.5, 1, 2 and 4 mg/kg) could induce CPP and it was found that METH with the dose of 0.5 mg/kg was more potent than other doses. In extinction phase, rats were put in the CPP box for 30 min per day for 8 consecutive days. After extinction, animals were exposed to restraint stress (3-h period, as an acute stress) 60 min before subcutaneous administration of ineffective dose of METH (0.125 mg/kg) in order to reinstate the extinguished METH-induced CPP. For induction of the chronic stress during extinction phase, the animals were exposed to the restraint stress for one hour per day.

Results:

The results showed that the effective dose of METH to induce CPP was 0.5 mg/kg. Based on the results, physical stress (restraint stress) whether acute and chronic, can significantly induce reinstatement of METH-induced CPP (P˂0.001) in extinguished animals.

Conclusion:

Additionally, the chronic restraint stress could reduce duration of extinction (maintenance) of METH-induced CPP. It seems that exposure to the stress induces the relapse in abstinent amphetamine, but acute and chronic situation have a different reaction.

Functional roles of orexin/hypocretin receptors in reward circuit

Since its first discovery in 1998, it has become clear that the orexinergic system plays an important role in regulating a number of functions including food, sex, social connections, and most prominently reward-related behaviors. Orexinergic neurons in the lateral hypothalamus project extensively to other brain areas, two most important of which are the ventral tegmental area and the nucleus accumbens that are involved in reward processing. In this review, we have presented the work in our laboratory along with the work of others and have discussed the possible functions we can infer from the research. We discuss the anatomy of the orexinergic system and its components followed by a presentation of other connected brain areas. The second part of this review discusses observed results from the morphine conditioned place preference test that sheds light on the possible role of the involved areas in reward processing. The complex circuits involved in reward processing are only beginning to be understood and we need to deepen our understanding regarding the nature of the interactions between all brain areas involved.

Protective Effects of Cyperus Rotundus Extract on Amyloid β-Peptide (1-40)-Induced Memory Impairment in Male Rats: A Behavioral Study

INTRODUCTION

The Alzheimer Disease (AD) is the most common form of dementia that leads to memory impairment. As the oxidative stress plays an important role in AD pathogenesis, the current study aimed at examining the protective effects of Cyperus Rotundus as an antioxidant on amyloid β (Aβ)-induced memory impairment.

METHODS

Twenty-eight Wistar male rats received intrahippocampal (IHP) injection of the Aβ (1-40) and C. rotundus (400 mg/kg, intraperitoneally). Spatial memory was assessed by the Morris water-maze (MWM) task.

RESULTS

In the MWM, Aβ (1-40) significantly increased escape latency and traveled distance (P<0.001). The administration of C. rotundus attenuated the Aβ-induced memory impairment in the MWM task.

CONCLUSION

The current study findings showed that C. Rotundus could improve the learning impairment, following the Aβ treatment, and it may lead to an improvement of AD-induced cognitive dysfunction.

The Role of Resilience and Age on Quality of life in Patients with Pain Disorders

The quality of life (QOL) has been defined as ''a person's sense of well-being that stems from satisfaction or dissatisfaction with the areas of life that are important to him/her''. Age was also significantly associated with several functional limitations such as illness, and physical restrictions. The concept of ''resilience'' refers to successful adaptation that unfolds within a context of significant and usually debilitating adversity or life stress. The ability to adapt to pain may play an important role in maintaining the QOL. In this study, we investigated the role of resilience and age in various domains of quality of life such as physical, psychological, social and environmental domains. In this study, 290 adult patients (146 men, 144 women) completed the Connor-Davidson Resilience Scale and the WHOQOL-BREF questionnaire. Moreover, we illustrated several demographic variables. The results were analyzed using SPSS version 19.0 and means, descriptive correlation and regression were calculated. Our data revealed that resilience and age could significantly anticipate the QOL and physical aspect (P<0.001). In psychological, social and environmental domains resilience but not the age could significantly predict this domains. In addition, it is noticeable that the effect of resilience on the prediction of QOL is much more obvious in the psychological domain.. In conclusion, resilience is more important factor than the age in prediction of life quality (QOL) in persons suffering from chronic pain.

Prediction of Quality of life by Self-Efficacy, Pain Intensity and Pain Duration in Patient with Pain Disorders

The quality of life (QOL) has been defined as "a person's sense of well-being that stems from satisfaction or dissatisfaction with the areas of life that are important to him/her". It is generally accepted that pain intensity and duration have a negative impact on the QOL. One specific type of control is "self-efficacy", or the belief that one has the ability to successfully engage in specific actions. The ability to adapt to pain may play an important role in maintaining the QOL. In this study, we investigated the role of self-efficacy, pain intensity, and pain duration in various domains of quality of life such as physical, psychological, social and environmental domains. In this study, 290 adult patients (146 men, 144 women) completed coping self-efficacy and the WHOQOL-BREF Questionnaire. Moreover, we illustrated numerical rating scale for pain intensity. The results were analyzed using SPSS version of 19.0 and means, descriptive correlation, and regression were calculated. Our data revealed that self-efficacy but not the pain duration could significantly anticipate the QOL and its four related domains (P<0.001). In addition, it is noticeable that the effect of self-efficacy on the prediction of QOL is much more obvious in the psychological domain. However, the pain intensity could predict all of the QOL domains (P<0.001) except social and environmental ones. In conclusion, to predict the quality of life (QOL) in person suffering from chronic pain, self-efficacy and pain intensity are more important factors than the pain duration and demographic variables.

Orexin A in the ventral tegmental area induces conditioned place preference in a dose-dependent manner: involvement of D1/D2 receptors in the nucleus accumbens

It has been shown that orexin A in the ventral tegmental area (VTA) is necessary for development of morphine place preference. Additionally, D1 and D2 dopamine receptors in the nucleus accumbens (NAc) have critical roles in motivation and reward. However, little is known about the function of orexin in conditioned place preference (CPP) in rats and involvement of D1/D2 receptors in the NAc. In the present study, we investigated the effect of direct administration of orexin A into the VTA, and examined the role of intra-accumbal dopamine receptors in development (acquisition) of reward-related behaviors in the rats. Adult male Wistar rats were unilaterally implanted by two separate cannulae into the VTA and NAc. The CPP paradigm was used, and, conditioning score and locomotor activity were recorded by Ethovision software. The results showed that unilateral intra-VTA administration of orexin A (27, 53 and 107 ng/0.3 μl saline) during conditioning phase induced CPP in a dose-dependent manner. The most effective dose of intra-VTA orexin-A in eliciting CPP was 107 ng. However, intra-NAc administration of SCH 23390 (0.25, 1 and 4 μg/0.5 μl saline), a D1 receptor antagonist, and sulpiride (0.25, 1 and 4 μg/0.5 μl DMSO), a D2 receptor antagonist, inhibited the development of orexin-induced CPP. The inhibitory effect of D2 but not D1 receptor antagonist was exerted in a dose-dependent manner. It is supposed that the activation of VTA dopaminergic neuron by orexin impresses the D2 receptors more than D1 receptors in the NAc.

Changes in phosphorylation of CREB, ERK, and c-fos induction in rat ventral tegmental area, hippocampus and prefrontal cortex after conditioned place preference induced by chemical stimulation of lateral hypothalamus

Experimental evidence indicates that chemical stimulation of lateral hypothalamus (LH) by carbachol can produce conditioned place preference (CPP) in rats. Several lines of evidence have shown that cAMP-response element binding protein (CREB), extracellular signal-regulated kinase (ERK), and c-fos have pivotal role in CPP induced by drugs of abuse, such as morphine, cocaine, nicotine, and alcohol. Therefore, in the present study, we investigated the changes in phosphorylated-CREB (p-CREB) and -ERK (p-ERK), and c-fos induction within ventral tegmental area (VTA), hippocampus and prefrontal cortex (PFC) after the acquisition of CPP induced by intra-LH administration of carbachol. Animals were unilaterally implanted by cannula into LH. For chemical stimulation of LH, carbachol (250 nmol/0.5 μl saline) was microinjected once each day, during 3-day conditioning phase (acquisition period) of CPP paradigm. After the acquisition period, the brains were removed, and p-CREB and p-ERK, and c-fos induction in the ipsilateral VTA, hippocampus and PFC were measured by Western blot analysis. The results indicated a significant increase in level of phosphorylated CREB (P<0.01) in VTA, and PFC (P<0.05), during LH stimulation-induced CPP, while its level decreased in hippocampus (P<0.05). Also, in aforementioned regions, an increase in c-fos level was observed, but this enhancement in PFC was not significant. Moreover, p-ERK changed in these areas, but not significantly. Our findings suggest that studying the intracellular signals and their changes, such as phosphorylated-CREB, can elucidate a functional relationship between LH and other brain structures involved in reward processing in rats.