Intra-nucleus-accumbens SKF38393 improved the impaired acquisition of morphine-conditioned place preference in depression-like rats

Depression in Chinese men with methamphetamine dependence: Prevalence, correlates and relationship with alexithymia

BACKGROUND

The comorbidity between substance use disorder and major depressive disorder is a typical dual diagnosis in the field of substance addiction. However, the prevalence and correlates of depression in methamphetamine addicts and whether it is associated with drug craving and alexithymia have been rarely reported in the Chinese population.

METHODS

We recruited 585 methamphetamine-dependent males from a drug rehabilitation center in China and 203 healthy controls. Demographic and drug use data were collected. Depression was assessed using the Mini International Neuropsychiatric Interview (M.I.N·I.). Methamphetamine cravings and alexithymia were assessed using the Desire for Drugs Questionnaire (DDQ) and the Toronto Alexithymia Scale (TAS).

RESULTS

The prevalence rate of depression in methamphetamine-dependent men was 16.58 % (97/585). The scores of DDQ desire and intention, DDQ negative reinforcement, total DDQ, difficulty identifying feelings (DIF), difficulty describing feelings (DDF), and total TAS score of depressed patients were higher than those of non-depressed patients. However, only DDQ negative reinforcement score, DIF, DDF, and total TAS score remained significant after Bonferroni correction. Additionally, logistic regression analysis found that age, DIF score, and DDQ negative reinforcement score were significant factors contributing to depression in methamphetamine-dependent men.

CONCLUSION

Our findings suggest that the prevalence of depression is significantly higher in methamphetamine-dependent men than in the healthy Chinese population. Furthermore, age, components of alexithymia and drug craving are risk factors for depression in methamphetamine addicts.

Maternal deprivation effect on morphine-induced CPP is related to changes in Opioid receptors in selected rat brain regions (hippocampus, prefrontal cortex, and nucleus accumbens)

Early-life environmental conditions affect offspring's development. Maternal deprivation (MD) can induce persistent changes that give rise to neuropsychiatric diseases including substance abuse disorders. However, long-lasting mechanisms that determine vulnerability to drug addiction remain unknown. We hypothesized that MD could induce changes in Opioid system, HPA (hypothalamic-pituitary-adrenal) axis, and BDNF (brain-derived neurotrophic factor), so may be involved in the drug abuse in later life. Male offspring of Wistar rats (n=8 per group) were subjected to 3h of daily MD during postnatal days 1-14. In adulthood, morphine-induced CPP (conditioned place preference) was investigated using two doses of morphine (3 and 5mg/kg). Serum corticosterone level was measured by ELISA method. The expression level of genes in selected brain regions (hippocampus, prefrontal cortex, and nucleus accumbens) was determined by qPCR (quantitative PCR). A greater morphine-induced CPP was observed in MD rats with 3 and 5mg/kg morphine compared to controls. MD group had a higher corticosterone level. A significant decrease was observed in the expression of BDNF gene (in all of the selected brain regions) and GR (glucocorticoid receptor) gene (in the hippocampus and nucleus accumbens) in MD rats. Also, a significant increase in the expression of μ Opioid receptor (in all of the selected brain regions) and κ Opioid receptor (in the prefrontal cortex and nucleus accumbens) was observed in MD rats. Our results suggest that MD induces alterations in the HPA axis function, BDNF level, and Opioid receptors system that enhance vulnerability to morphine at adulthood.

The Nucleus Accumbens: A Common Target in the Comorbidity of Depression and Addiction

The comorbidity of depression and addiction has become a serious public health issue, and the relationship between these two disorders and their potential mechanisms has attracted extensive attention. Numerous studies have suggested that depression and addiction share common mechanisms and anatomical pathways. The nucleus accumbens (NAc) has long been considered a key brain region for regulating many behaviors, especially those related to depression and addiction. In this review article, we focus on the association between addiction and depression, highlighting the potential mediating role of the NAc in this comorbidity via the regulation of changes in the neural circuits and molecular signaling. To clarify the mechanisms underlying this association, we summarize evidence from overlapping reward neurocircuitry, the resemblance of cellular and molecular mechanisms, and common treatments. Understanding the interplay between these disorders should help guide clinical comorbidity prevention and the search for a new target for comorbidity treatment.

Effects of inactivating the agranular or granular insular cortex on the acquisition of the morphine-induced conditioned place preference and naloxone-precipitated conditioned place aversion in rats

Recent studies have indicated that the insula underlies affective learning. Although affective learning is well-established in the development of opiate addiction, the role of insula in this context remains unclear. To elucidate the organization of opiate-related affective learning within the insular cortex, we reversibly inactivated each of two major subdivisions of the insula in rats and tested the effects of this inactivation on the acquisition of morphine-induced conditioned place preference (CPP) and conditioned place aversion (CPA) induced by naloxone-precipitated acute morphine withdrawal. Results showed that inactivation of the primary interoceptive posterior granular insula (GI), but not that of the high-order anterior agranular insula (AI), disrupted the acquisition of CPP and that both GI and AI inactivation impaired the acquisition of CPA. These data suggest that the insular cortex is involved in positive and negative affective learning related to opiate addiction. In particular, the GI appears to be critical for both forms of affective learning, whereas the AI is crucial for learning associated with negative affects induced by opiate withdrawal.