Rhynchophylline inhibits methamphetamine dependence via modulating the miR-181a-5p/GABRA1 axis.

ETHNOPHARMACOLOGICAL RELEVANCE: Uncaria rhynchophylla (Miq.) Miq. ex Havil. is a plant species that is routinely devoted in traditional Chinese medicine to treat central nervous system disorders. Rhynchophylline (Rhy), a predominant alkaloid isolated from Uncaria rhynchophylla (Miq.) Miq. ex Havil., has been demonstrated to reverse methamphetamine-induced (METH-induced) conditioned place preference (CPP) effects in mice, rats and zebrafish. The precise mechanism is still poorly understood, thus further research is necessary. AIM OF STUDY: This study aimed to investigate the role of miRNAs in the inhibitory effect of Rhy on METH dependence. MATERIALS AND METHODS: A rat CPP paradigm and a PC12 cell addiction model were established. Microarray assays were used to screen and identify the candidate miRNA. Behavioral assessment, real-time PCR, dual-luciferase reporter assay, western blotting, stereotaxic injection of antagomir/agomir and cell transfection experiments were performed to elucidate the effect of the candidate miRNA and intervention mechanism of Rhy on METH dependence. RESULTS: Rhy successfully reversed METH-induced CPP effect and the upregulated miR-181a-5p expression in METH-dependent rat hippocampus and PC12 cells. Moreover, suppression of miR-181a-5p by antagomir 181a reversed METH-induced CPP effect. Meanwhile, overexpression of miR-181a-5p by agomir 181a in combination with low-dose METH (0.5 mg/kg) elicited a significant CPP effect, which was blocked by Rhy through inhibiting miR-181a-5p. Finally, the result demonstrated that miR-181a-5p exerted its regulatory role by targeting γ-aminobutyric acid A receptor α1 (GABRA1) both in vivo and in vitro. CONCLUSION: This finding reveals that Rhy inhibits METH dependence via modulating the miR-181a-5p/GABRA1 axis, which may be a promising target for treatment of METH dependence.

Expression of miR-133a-5p and ROCK2 in Heart in Methamphetamine-Induced Rats and Intervention of Rhynchophylline.

INTRODUCTION: Rhynchophylline, as a traditional Chinese medicine, was used for the treatment of drug addiction. OBJECTIVE: To investigate miRNAs expression profile in the rat hearts of methamphetamine dependence and the intervention mechanisms of rhynchophylline. MATERIALS AND METHODS: This study detected the expression profile of miRNAs in the methamphetamine-induced rat hearts by microarray and verified the expression of miR-133a-5P and Rho-associated, coiled-coil containing protein kinase 2 (ROCK2) protein. RESULTS: After conditioned place preference training, methamphetamine significantly increased the time spent in the drug-paired compartment, while rhynchophylline and MK-801 could reduce the time. Cluster analysis results of miRNAs showed that compared with the control group, the expression of miR-133a-5p in methamphetamine-induced rat hearts was decreased significantly; rhynchophylline could significantly increase the expression of miR-133a-5p. The result was verified by real-time polymerase chain reaction. The results of target gene predictive software and related research showed that ROCK2 protein may be the target gene of miR-133a-5p. The immunohistochemistry results of heart tissues showed that the expression of ROCK2 protein was significantly upregulated in the methamphetamine group and downregulate in the rhynchophylline group; the difference between the MK-801 group and the methamphetamine group was not significant. The result of western blot was consistent with the immunohistochemistry. CONCLUSION: The active ingredient of Chinese herbal medicine rhynchophylline can effectively inhibit the formation of methamphetamine-dependent conditional place preference (CPP) effect in rats to some extent. MiR-133a-5p may participate in the cardioprotective effects of CPP rats by targeting ROCK2.

Lifetime methamphetamine dependence is associated with cerebral microgliosis in HIV-1-infected adults.

Methamphetamine (Meth) use is common among HIV-infected persons. It remains unclear whether Meth dependence is associated with long-lasting degenerative changes in the brain parenchyma and microvasculature of HIV-infected individuals. We examined the postmortem brains of 78 HIV-infected adults, twenty of whom were diagnosed with lifetime Meth dependence (18 past and two current at the final follow-up visit). Using logistic regression models, we analyzed associations of Meth with cerebral gliosis (immunohistochemistry for ionized calcium-binding adapter molecule-1 (Iba1) and glial fibrillary acidic protein (GFAP) in frontal, temporo-parietal, and putamen-internal capsule regions), synaptodendritic loss (confocal microscopy for synaptophysin (SYP) and microtubule-associated protein-2 (MAP2) in frontal cortex), ß-amyloid plaque deposition (immunohistochemistry in frontal and temporo-parietal cortex and putamen), and arteriolosclerosis (histopathology in forebrain white matter). We found that Meth was associated with marked Iba1 gliosis in the temporo-parietal region (odds ratio, 4.42 (95 % confidence interval, 1.36, 14.39), p = 0.014, n = 62), which remained statistically significant after adjusting for HIV encephalitis, white matter lesions, and opportunistic diseases (n = 61); hepatitis C virus seropositivity (n = 54); and lifetime dependence on alcohol, opiates, and cannabis (n = 62). There was no significant association of Meth with GFAP gliosis, SYP or MAP2 loss, ß-amyloid plaque deposition, or arteriolosclerosis. In conclusion, we found lifetime Meth dependence to be associated with focal cerebral microgliosis among HIV-infected adults, but not with other brain degenerative changes examined. Some of the changes in select brain regions might be reversible following extended Meth abstinence or, alternatively, might have not been induced by Meth initially.

Biological treatments for amfetamine dependence : recent progress.

Amfetamine abuse has grown into a worldwide epidemic. Methamfetamine, a derivative of amfetamine made from readily accessible chemicals, has plagued the US since the 1960s, with an alarming recent surge in the numbers of those meeting the criteria for amfetamine abuse and dependence. We review this problem using a computerised literature search (PubMed 1964-2007) to summarise knowledge from animal and human studies about treatments for amfetamine dependence, while exploring the potential of pharmacogenetics to help uncover new treatment targets. Several promising therapeutic targets have come from animal models of reward, drug-taking behaviour and withdrawal. Although preclinical and selected clinical results have been promising, clinical studies have yielded inconsistent results. To improve these outcomes, pharmacogenetic studies may be used to identify candidate alleles that predict therapeutic response. Exciting preclinical findings and a steady progression of clinical results offer hope for the development of a treatment for amfetamine dependence.

Cocaine-amphetamine regulated transcript (CART) expression is not regulated by amphetamine.

Cocaine-amphetamine-regulated transcript (CART) is one of the most abundantly expressed mRNAs in the rat hypothalamus. Nevertheless, CART was identified from striatal extracts as a transcript induced acutely by cocaine or amphetamine treatment. In the hypothalamus, CART mRNA expression has been shown to be regulated by leptin, and CART peptides have been implicated in feeding behavior and in the regulation of the HPA-axis. In the present experiments we have re-examined the effects of amphetamine on CART expression in the forebrain and in the hypothalamus by the use of in situ hybridization. Although we used the same amphetamine treatment paradigm as that originally reported we failed to demonstrate any regulation of CART mRNA levels by amphetamine in either the forebrain or in the hypothalamus. The present results question the acronym chosen for this predominantly hyopthalamic neuropeptide.

Effect of amphetamine on the expression of the metabotropic glutamate receptor 5 mRNA in developing rat brain.

Mechanisms underlying the acute effects of amphetamine (AMP) were examined by monitoring the expression of metabotropic glutamate receptor 5 (mGluR5) and specific 3H-glutamate binding in the developing rat brain. Each of the postnatal day (P) 4, P21 and P60 rats received one intraperitoneal injection of AMP, 5 mg/kg or saline and were sacrificed one hour later. In situ hybridization analysis revealed that the AMP treatment raised the levels of the mGluR5 mRNA by 9-28% in the neurons of the layer 5 of motor and somatosensory cortices, whereas reduced the levels by 12-28% in the layer 5 of perirhinal cortex and the ventromedial part of caudate-putamen of the 3 ages. In the layer 2/3 neurons of cingular cortex, an 18% higher and 14% and 22% lower than control levels of the mRNA were detected in the P4 and in the P21 and P60 rats injected with AMP. Moreover, the levels of mGluR5 mRNA in the hippocampi and dentate gyri were elevated by AMP to 110-151% of controls in the rats of 3 ages. Reversible 3H-glutamate binding assay showed an increase of 25% and a 12% decrease in the binding levels in the cortices of AMP-treated P4 and P21 rats. The AMP administration also produced a 27% reduction and 62% elevation in the binding of the hippocampi of P4 and P60 rats. The results reveal age- and region-dependent changes in the expression of the glutamate receptors induced by AMP and may indicate differential plastic capability of the neurons to the drug perturbation.