Ovarian hormones prevent methamphetamine-induced anxiety-related behaviors and neuronal damage in ovariectomized rats

Role of sex hormones in the effects of sleep deprivation on methamphetamine reward memory

Sleep deficiency is known as an important risk factor for relapse to drug abuse, especially for the powerful psychostimulant methamphetamine (METH). On the other hand, both drug addiction and sleep neurobiology are affected by sex hormones. We, therefore, aimed to examine the probable effects of sleep deprivation (SD) on methamphetamine (METH) reward memory in male and female rats. Moreover, we asked if sex hormones influence the effects of SD on METH reward memory. Adult male and female Wistar rats were divided into two main groups, sham and gonadectomized groups. Three weeks later, they were conditioned to receive METH (2 mg/kg, i.p.) in the conditioned place preference. METH reward memory was then reinstated following a 10-day extinction period. SD was induced for 72 h, either before or after extinction, in different groups. In gonadectomized animals, they daily received either subcutaneous administration of estrogen (5 μg/0.1 ml oil) or progesterone (2 mg/0.1 ml oil) or dihydrotestosterone (25 mg/0.1 ml oil) for thirteen days, from post-conditioning day to reinstatement session. We found that SD facilitated relapse to METH reward memory, depending on the time interval between SD and METH reinstatement. Furthermore, we found that estrogen and SD showed synergistic effects to facilitate METH reward memory, whereas testosterone and progesterone revealed inhibitory effects in the controls, but not in the SD, animals. Our findings would seem to suggest that sex hormones should be considered as determinant factors to manage METH abuse and relapse to METH seeking/taking behavior, especially for those with sleep deficiency.

Estradiol administration increases anxiety-like behavior following chronic escalating morphine administration in hormone-replaced ovariectomized female rats

Withdrawal from opioids can induce a state of anxiety and irritability. This negative state can facilitate continued drug taking, as the administration of opioids can alleviate unpleasant symptoms associated with acute and protracted withdrawal. It is, therefore, of interest to investigate factors that can contribute to the severity of anxiety during periods of abstinence. One such factor is the fluctuation of ovarian hormones. Evidence from a non-opioid drug indicates that estradiol increases, while progesterone decreases anxiety during withdrawal. However, no work has yet studied how ovarian hormones might influence the severity of anxiety during withdrawal from opioids. To explore this, we ovariectomized female rats and provided a four-day repeating cycle of ovarian hormone administration (Day 1: estradiol, Day 2: estradiol, Day 3: progesterone, Day 4: peanut oil). Male rats were given sham surgeries and administered peanut oil daily in lieu of hormone replacement. All rats received twice daily injections of morphine (or 0.9 % saline) for 10 days total at a dose that doubled every two days (2.5 mg/kg, 5 mg/kg, 10 m/kg, 20 mg/kg, 40 mg/kg). Rats underwent spontaneous withdrawal and were tested for anxiety-like behaviors 12 and 108 h after the last morphine treatment. At 12 h, morphine-withdrawn female rats treated with estradiol on the day of testing displayed significantly more anxiety-like behavior in light-dark box testing than female morphine-withdrawn and (marginally) male morphine-withdrawn rats receiving vehicle that day. Somatic withdrawal behaviors (wet dog shakes, head shakes, writhing) were also taken every 12 h through 108 h. We found no meaningful contribution of sex or hormone for these measures. This study is the first of its kind to provide evidence that ovarian hormones influence anxiety-like behavior during morphine withdrawal.

Obeticholic acid protects against methamphetamine-induced anxiety-like behavior by ameliorating microbiota-mediated intestinal barrier impairment

Methamphetamine (Meth) abuse can cause severe anxiety disorder and interfere with gut homeostasis. Obeticholic acid (OCA) has emerged as a protective agent against diet-related anxiety that improves gut homeostasis. The potential for OCA to ameliorate Meth-induced anxiety, and the microbial mechanisms involved, remain obscure. Here, C57/BL6 mice were intraperitoneally injected with Meth (15 mg/kg) to induce anxiety-like behavior. 16 S rRNA sequence analysis and fecal microbiome transplantation (FMT) were used to profile the gut microbiome and evaluate its effects, respectively. Orally administered OCA was investigated for protection against Meth-induced anxiety. Results indicated that Meth mediated anxiety-like behavior, aroused hippocampal neuroinflammation through activation of the TLR4/MyD88/NF-κB pathway, weakened intestinal barrier and disturbed the gut microbiome. Specifically, abundance of anxiety-related Rikenella was increased. FMT from Meth-administrated mice also weakened intestinal barrier and elevated serum LPS, inducing hippocampal neuroinflammation and anxiety-like behavior in recipient mice. Finally, OCA pretreatment ameliorated Meth-induced impairment of gut homeostasis by reshaping the microbial composition and improving the intestinal barrier. Meth-induced anxiety-like behavior and hippocampal neuroinflammation were also ameliorated by OCA pretreatment. These preliminary findings reveal the crucial role of gut microbiota in Meth-induced anxiety-like behavior and neuroinflammation, highlighting OCA as a potential candidate for the prevention of Meth-induced anxiety.

Noninvasive Vagus Nerve Stimulation in the Treatment of Methamphetamine Use Disorder: A Review Article

: Methamphetamine (MA) use and the mortality it causes are increasing worldwide. The neurobiological mechanisms underlying the destructive effects of MA use are complex; however, there is much evidence that MA induces the dysfunction of monoaminergic transmission and causes oxidative stress, neuroinflammation, gliosis, and apoptosis. These toxic effects are associated with cardiotoxicity and neurotoxicity and with an imbalance in the autonomic nervous system, which altogether manifest themselves in clinical symptoms, such as neuropsychiatric disorders and cardiovascular diseases. There is no approved treatment for methamphetamine use disorder (MUD) despite all efforts made to date. The behavioral and pharmacological approaches currently used for the treatment of MUD are not completely effective. In this study, it is hypothesized that the stimulation of the vagus nerve and biological pathways underlying the processes of this stimulation might be effective as adjunctive therapy. Despite the potential effects of vagus nerve stimulation (VNS) to improve MUD, no study has yet examined the clinical potential effects of VNS in patients with the disorder. Therefore, further studies, including experimental and clinical trials, are needed to examine the effects of VNS on MUD.

Maternal sleep deprivation affects extinction and reinstatement of methamphetamine reward memory in male offspring: role of the D1-like and D2-like dopamine receptors

Maternal sleep-deprivation (MSD) has been shown to induce stress, hyperactivity, and risk taking behavior in the offspring; howbeit, it is not yet clear whether it may also affect vulnerability to psychostimulant abuse in the offspring. We aimed to determine whether MSD affects extinction and reinstatement of methamphetamine (METH) reward memory in the offspring and also to evaluate the possible role of dopamine D1-like and D2-like receptors in these processes. Thirty-day-old male offspring born to control and sleep-deprived dams (during the third week of pregnancy) were trained to acquire METH-induced place preference (2 mg/kg., i.p.). METH reward memory was then reinstated following an 8-day period of extinction. The offspring received SCH 23390 (0.03 or 0.1 mg/kg, i.p.) or sulpiride (20 or 60 mg/kg, i.p.) as antagonists of dopamine D1-like and D2-like receptors, respectively, either immediately after each daily extinction session or prior to the reinstatement session. MSD postponed METH extinction and facilitated METH reinstatement in the offspring. SCH 23390 facilitated METH extinction and decreased reinstatement of the extinguished METH preference. Sulpiride in the offspring from sleep-deprived dams facilitated METH extinction, but it did not affect reinstatement of the extinguished METH place preference. It seems that MSD may enhance vulnerability to METH abuse in the offspring. Furthermore, both dopamine D1-like and D2-like receptors may mediate METH extinction in the offspring born to the sleep-deprived dams; however, only the dopamine D1 receptor may play an important role in reinstating the extinguished METH reward memory in the offspring.

Local efficiency analysis of restingstate functional brain network in methamphetamine users

This study set out to assess restingstate functional connectivity (rs-FN) and graph theorybased local efficiency within the left and right hemispheres of methamphetamine (MA) abusers. Functional brain networks of 19 MA abusers and 21 control participants were analyzed using restingstate fMRI. Graph edges in functional networks of the brain were defined and recurrence plot was used. We found that MA abuse may be accompanied by alterations of rs-FN within the defaultmode network (DMN), executive control network (ECN), and the salience network (SN) in both hemispheres of the brain. We also observed that such effects of MA may be correlated with duration of MA abuse and abstinence in many components of the DMN and SN. The results would seem to suggest that MAinduced alterations of local efficiency may, in part, account for maladaptive decision making, deficits in executive function and control over drug seeking/taking, and relapse.

Effects of clozapine and risperidone antipsychotic drugs on the expression of CACNA1C and behavioral changes in rat 'Ketamine model of schizophrenia

Calcium Voltage-Gated Channel Subunit Alpha1 C (CACNA1C) is one of the most important genes associated with schizophrenia. In this study, 45 male Wistar rats were divided into 5 groups of saline, control, ketamine, clozapine, and risperidone. Animals in ketamine, risperidone, and clozapine groups received ketamine (30 mg/kg-i.p.) for 10 days. After the last injection of ketamine, we started injecting clozapine (7.5 mg/kg-i.p.), risperidone (1 mg/kg-i.p.), up to 28 days. Twenty-four hours after the last injection, open field, social interaction, and elevated plus-maze tests and gene expression in hippocampus were performed. The results of the social interaction test revealed a significant decrease in cumulative time with ketamine, compared with the saline group, and an increase with clozapine and risperidone compared with the ketamine group. Moreover, results from the elevated plus-maze test demonstrated a critical decrease in open arm time and increase in close arm time with ketamine compared with saline, as well as increased in open arm time with risperidone compared with ketamine. Further results revealed a significant increase in rearing and grooming with ketamine compared to saline, as well as a decrease with risperidone and clozapine compared to ketamine. There were no significant differences in CACNA1C gene expression between groups in the rat hippocampus. In brief, the results of this study indicated that clozapine and risperidone could partially improve cognitive impairments in the rat. However, our findings demonstrated that this treatment is not related to CACNA1C gene expression.

Maternal separation impairs mother's cognition 1 month beyond the separation

OBJECTIVE

Separation of pups from their dam during the infancy not only has detrimental effects on the pups' brain but also affects dams' behavior. Postpartum stress may affect mothers' cognitive functions. In the present study, by using a 180-min day^-1 maternal separation (MS) paradigm, we assessed anxiety-like behavior and locomotor activity of rat dams which experienced separation from postnatal day (PND) 1 until weaning. We tried for the first time to clarify whether such separation impairs dam's performance in the Morris water maze.

METHOD

We assessed dams' behavior at three time points: 24 h, 1 week, and 1 month after weaning. Therefore, the six groups consisted of control (CTRL) 24 h, 1 week, and 1 month and MS 24 h, 1 week, and 1 month, which was allocated in this study.

RESULTS

Our results revealed that although MS-24 h and MS-1 week groups had intact locomotor activity, MS-1 month group showed less locomotor activity in the open field. Moreover, MS-induced anxiety-like behavior was more pronounced in MS-1 week and MS-1 month dams. Spatial learning and memory was also impaired only in MS-1 month dams.

CONCLUSION

We can conclude that MS induces cognitive impairments in dam that may appear not immediately after the separation but a few weeks after such stressful event.

Behaviors Related to Psychiatric Disorders and Pain Perception in C57BL/6J Mice During Different Phases of Estrous Cycle

Robust sex difference among humans regarding psychiatry- and pain-related behaviors is being researched; however, the use of female mice in preclinical research is relatively rare due to an unchecked potential behavioral variation over the estrous cycle. In the present study, a battery of psychiatry- and pain-related behaviors are examined under physiological condition in female C57BL/6J mice over different estrous cycle phases: proestrus, estrous, metestrous, diestrous. Our behavioral results reveal that there is no significant difference over different phases of the estrous cycle in social interaction test, sucrose preference test, tail suspension test, open field test, marble burying test, novelty-suppressed feeding test, Hargreaves thermal pain test, and Von Frey mechanical pain test. These findings implicate those psychiatry- and pain-related behaviors in normal female C57BL/6J mice appear to be relatively consistent throughout the estrous cycle; the estrous cycle might not be a main contributor to female C57BL/6J mice’s variability of behaviors.