Medication of l-tetrahydropalmatine significantly ameliorates opiate craving and increases the abstinence rate in heroin users: a pilot study

Natural Product-Inspired Dopamine Receptor Ligands

Due to their evolutionary bias as ligands for biologically relevant drug targets, natural products offer a unique opportunity as lead compounds in drug discovery. Given the involvement of dopamine receptors in various physiological and behavioral functions, they are linked to numerous diseases and disorders such as Parkinson's disease, schizophrenia, and substance use disorders. Consequently, ligands targeting dopamine receptors hold considerable therapeutic and investigative promise. As this perspective will highlight, dopamine receptor targeting natural products play a pivotal role as scaffolds with unique and beneficial pharmacological properties, allowing for natural product-inspired drug design and lead optimization. As such, dopamine receptor targeting natural products still have untapped potential to aid in the treatment of disorders and diseases related to central nervous system (CNS) and peripheral nervous system (PNS) dysfunction.

Natural products as the therapeutic strategies for addiction

World Drug Report 2023 concluded that 296 million people abused drugs, 39.5 million became addiction and 494,000 died as a direct or indirect result of addiction. Addiction has become a growing problem that affects individuals, their families, societies, countries and even the world. However, treatment for addiction is only limited to some developed countries because of the high cost, difficult implementation, and time consuming. Therefore, there is an urgent need to develop a low-cost, effective drug for the development of addiction treatment in more countries, which is essential for the stability and sustainable development of the world. In this review, it provided an overview of the abuse of common addictive drugs, related disorders, and current therapeutic regimen worldwide, and summarized the mechanisms of drug addiction as reward circuits, neuroadaptation and plasticity, cognitive decision-making, genetics, and environment. According to their chemical structure, 43 natural products and 5 herbal combinations with potential to treat addiction were classified, and their sources, pharmacological effects and clinical trials were introduced. It was also found that mitragine, ibogine, L-tetrahydropalmatine and crocin had greater potential for anti-addiction.

Analysis and study of the mechanism of narcotic addiction and withdrawal

Narcotic drugs refer to drugs that have anesthetic effects on the central nervous system, and they easily produce physical dependence and mental dependence and can be addictive due to continuous use, abuse or unreasonable use. In this paper, bioinformatics and data analysis and mining techniques were used to analyze the methylation differences in transcriptional and clinical data of narcotic addiction in public databases, to explore the mechanism of narcotic addiction, and to mine some norepinephrine drugs. This study confirmed the possibility of using norepinephrine as an auxiliary drug for drug addiction rehabilitation. In addition, we also conducted a similar analysis on the addiction of three drugs. The results showed that the differences in the body caused by the ingestion of opiates and cocaine were significantly greater than those caused by the ingestion of methamphetamine.

Morphine Withdrawal-Induced Hyperalgesia in Models of Acute and Extended Withdrawal Is Attenuated by l-Tetrahydropalmatine

Effective pain control is an underappreciated aspect of managing opioid withdrawal, and its absence presents a significant barrier to successful opioid detoxification. Accordingly, there is an urgent need for effective non-opioid treatments to facilitate opioid detoxification. l-Tetrahydropalmatine (l-THP) possesses powerful analgesic properties and is an active ingredient in botanical formulations used in Vietnam for the treatment of opioid withdrawal syndrome. In this study, rats receiving morphine (15 mg/kg, i.p.) for 5 days per week displayed a progressive increase in pain thresholds during acute 23 h withdrawal as assessed by an automated Von Frey test. A single dose of l-THP (5 or 7.5 mg/kg, p.o.) administered during the 4th and 5th weeks of morphine treatment significantly improves pain tolerance scores. A 7-day course of l-THP treatment in animals experiencing extended withdrawal significantly attenuates hyperalgesia and reduces the number of days to recovery to baseline pain thresholds by 61% when compared to vehicle-treated controls. This indicates that the efficacy of l-THP on pain perception extends beyond its half-life. As a non-opioid treatment for reversing a significant hyperalgesic state during withdrawal, l-THP may be a valuable addition to the currently limited arsenal of opioid detoxification treatments.

High-Throughput Sequencing Reveals That Rotundine Inhibits Colorectal Cancer by Regulating Prognosis-Related Genes

Background: Rotundine is an herbal medicine with anti-cancer effects. However, little is known about the anti-cancer effect of rotundine on colorectal cancer. Therefore, our study aimed to investigate the specific molecular mechanism of rotundine inhibition of colorectal cancer. Methods: MTT and cell scratch assay were performed to investigate the effects of rotundine on the viability, migration, and invasion ability of SW480 cells. Changes in cell apoptosis were analyzed by flow cytometry. DEGs were detected by high-throughput sequencing after the action of rotundine on SW480 cells, and the DEGs were subjected to function enrichment analysis. Bioinformatics analyses were performed to screen out prognosis-related DEGs of COAD. Followed by enrichment analysis of prognosis-related DEGs. Furthermore, prognostic models were constructed, including ROC analysis, risk curve analysis, PCA and t-SNE, Nomo analysis, and Kaplan–Meier prognostic analysis. Results: In this study, we showed that rotundine concentrations of 50 μM, 100 μM, 150 μM, and 200 μM inhibited the proliferation, migration, and invasion of SW480 cells in a time- and concentration-dependent manner. Rotundine does not induce SW480 cell apoptosis. Compared to the control group, high-throughput results showed that there were 385 DEGs in the SW480 group. And DEGs were associated with the Hippo signaling pathway. In addition, 16 of the DEGs were significantly associated with poorer prognosis in COAD, with MEF2B, CCDC187, PSD2, RGS16, PLXDC1, HELB, ASIC3, PLCH2, IGF2BP3, CLHC1, DNHD1, SACS, H1-4, ANKRD36, and ZNF117 being highly expressed in COAD and ARV1 being lowly expressed. Prognosis-related DEGs were mainly enriched in cancer-related pathways and biological functions, such as inositol phosphate metabolism, enterobactin transmembrane transporter activity, and enterobactin transport. Prognostic modeling also showed that these 16 DEGs could be used as predictors of overall survival prognosis in COAD patients. Conclusions: Rotundine inhibits the development and progression of colorectal cancer by regulating the expression of these prognosis-related genes. Our findings could further provide new directions for the treatment of colorectal cancer.

Levo-tetrahydropalmatine inhibits α4β2 nicotinic receptor response to nicotine in cultured SH-EP1 cells

Nicotine, a major component of tobacco, is highly addictive and acts on nicotinic acetylcholine receptors (nAChRs) to stimulate reward-associated circuits in the brain. It is well known that nAChRs play critical roles in mediating nicotine reward and addiction. Current FDA-approved medications for smoking cessation are the antidepressant bupropion and the nicotinic partial agonist varenicline, yet both are limited by adverse side effects and moderate efficacy. Thus, development of more efficacious medications with fewer side effects for nicotine addiction and smoking cessation is urgently needed. l-Tetrahydropalmatine (l-THP) is an active ingredient of the Chinese medicinal herb Corydalis ambigua that possesses rich neuropharmacological actions on dopamine (DA) receptors in the mesocorticolimbic dopaminergic reward pathway. L-THP has been explored as anti-addiction treatments for drug abuse including nicotine. However, the targets and mechanisms of l-THP-caused anti-nicotine effects are largely unknown. In this study we address this question by elucidating the effects of l-THP on human neuronal nAChRs using patch-clamp recordings. Human neuronal α4β2-nAChRs were heterologously expressed in SH-EP1 human epithelial cells. Bath application of nicotine (0.1-100 μM) induced inward currents, co-application of l-THP (3 μM) inhibited nicotine-induced currents in the transfected cells. L-THP-caused inhibition was concentration-dependent (the EC₅₀ values for inhibiting the peak and steady-state current were 18 and 2.1 μM, respectively) and non-competitive. Kinetic analysis of the whole-cell currents showed that l-THP slowed rising time and accelerated decay time constants. L-THP specifically modulated α4β2-nAChRs, as it did not affect α7-nAChRs or α1*-nAChRs (muscle type). Interestingly, two putative α4β2-nAChR isoforms, namely sazetidine A-activated, high-sensitive one (α4₂β2₃-nAChR) and cytisine-activated, low-sensitive one (α4₃β2₂-nAChR) were pharmacologically separated, and the low-sensitive one was more susceptible to l-THP inhibition than the high-sensitive one. In conclusion, we demonstrate that l-THP blocks neuronal α4β2-nAChR function, which may underlie its inhibition on nicotine addiction.

Recovery of superior frontal gyrus cortical thickness and resting-state functional connectivity in abstinent heroin users after 8 months of follow-up

Compared with healthy controls, heroin users (HUs) show evidence of structural and functional brain alterations. However, little is known about the possibility of brain recovery after protracted heroin abstinence. The purpose of this study was to investigate whether brain recovery is possible after protracted abstinence in HUs. A total of 108 subjects with heroin addiction completed structural and functional scans, and 61 of those subjects completed 8-month follow-up scans. Resting-state data and 3D-T1 MR images were collected for all participants, first at baseline and again after 8 months. Cognitive function and craving were measured by the Trail Making Test-A (TMT-A) and Visual Analog Scale for Craving, respectively. The cortical thickness and resting-state functional connectivity (RSFC) differences were then analyzed and compared between baseline and follow-up, and correlations were obtained between neuroimaging and behavioral changes. HUs demonstrated improved cognition (shorter TMT-A time) and reduced craving at the follow-up (HU2) relative to baseline (HU1), and the cortical thickness in the bilateral superior frontal gyrus (SFG) was significantly greater at HU2 than at HU1. Additionally, the RSFC of the left SFG with the inferior frontal gyrus (IFG), insula, and nucleus accumbens and that of the right SFG with the IFG, insula and orbitofrontal cortex (OFC) were increased at HU2. The changes in TMT-A time were negatively correlated with the RSFC changes between the left SFG and the bilateral IFG, the bilateral caudate, and the right insula. The changes in craving were negatively correlated with the RSFC changes between the left OFC and the bilateral SFG. Our results demonstrated that impaired frontal-limbic neurocircuitry can be partially restored, which might enable improved cognition as well as reduced craving in substance-abusing individuals. We provided novel scientific evidence for the partial recovery of brain circuits implicated in cognition and craving after protracted abstinence.

The Extract of Corydalis yanhusuo Prevents Morphine Tolerance and Dependence

The opioid epidemic was triggered by an overprescription of opioid analgesics. In the treatment of chronic pain, repeated opioid administrations are required which ultimately lead to tolerance, physical dependence, and addiction. A possible way to overcome this conundrum consists of a co-medication that maintains the analgesic benefits of opioids while preventing their adverse liabilities. YHS, the extract of the plant Corydalis yanhusuo, has been used as analgesic in traditional Chinese medicine for centuries. More recently, it has been shown to promote analgesia in animal models of acute, inflammatory, and neuropathic pain. It acts, at least in part, by inhibiting the dopamine D2 receptor, suggesting that it may be advantageous to manage addiction. We first show that, in animals, YHS can increase the efficacy of morphine antinociceptive and, as such, decrease the need of the opioid. We then show that YHS, when coadministered with morphine, inhibits morphine tolerance, dependence, and addiction. Finally, we show that, in animals treated for several days with morphine, YHS can reverse morphine dependence and addiction. Together, these data indicate that YHS may be useful as a co-medication in morphine therapies to limit adverse morphine effects. Because YHS is readily available and safe, it may have an immediate positive impact to curb the opioid epidemic.

Role of Levo-tetrahydropalmatine and its metabolites for management of chronic pain and opioid use disorders

BACKGROUND

Opioids have been prescribed to reduce suffering from pain and to enhance quality of life. Due to the addictive potential and the lack of other effective alternatives to treat severe acute and chronic pains, opioids remain a serious public health issue. While, opioids directly influence the drug-seeking behavior, tolerance and withdrawal processes, through neuroadaptation, the brain's endogenous opioid system also adapts in the presence of chronic pain and could contribute to the difficulty of treatment. Despite the seemingly obvious interaction between the presence of pain and opioid-abuse, little is known about the underlying mechanisms in the brain.

PURPOSE

To review the current understanding of the interaction mechanisms of neurotransmitter circuitries in pain modulation and reward in the brain and the effects of L-tetrahydropalmatine (L-THP) and its metabolites in pain management and opioid use disorder and gain a better insight on the pharmacological profile and in vivo effects of L-THP and its metabolites.

METHOD

A detailed literature search on available (preclinical and clinical) studies about the effects of L-THP and its metabolites against drug addiction and chronic pain has been performed. The data was collected using various search engines such as PubMed, ScienceDirect, Google scholar and articles in English up to December 2020 were included in this review.

RESULTS

L-THP and its metabolites demonstrated analgesic and anti-addiction effects. Due to their dual pharmacological properties (D1 partial agonist and D2 antagonist) these compounds could be used as molecular tools to provide a better understanding of the interactions between pain and addiction.

CONCLUSION

The available data confirms the potential of L-THP and its metabolites to treat both chronic pain and drug addiction. However, further clinical trials are needed to establish safety and efficacy.

A systematic review of integrative medicine for opioid withdrawal

INTRODUCTION

The United States has been battling an opioid epidemic for decades. As substance use disorders have grown, so too has investigation into treatment options, including integrative medicine approaches, for managing opioid withdrawal symptoms (OWS).

OBJECTIVES

This systematic review sought to assess the use of integrative medicine approaches for the alleviation of OWS in patients dependent on opioids and to summarize the available data.

METHODS

The authors searched using synonyms for opioids, substance use disorder, and integrative medicine and standardized searches in Embase, PubMed, and Cochrane Library. We also hand searched references for systematic reviews. This review did not include articles that could not be obtained as full-text publications via interlibrary loan. The review also excluded studies with interventions involving acupuncture because multiple systematic reviews on this approach already exist. In addition, we also excluded studies of therapy for opioid maintenance. We evaluated studies for inclusion based on the Jadad criteria. We compared opioid withdrawal outcomes of the studies to determine the efficacy of integrative medicine approaches.

RESULTS

The authors identified a total of 382 unique publications initially for possible inclusion through systematic searches. After applying inclusion and exclusion criteria, five studies met Jadad criteria. The authors identified an additional two studies for inclusion via hand searching. A total of seven studies included interventions consisting of passionflower, weinicom, fu-yuan pellet, jinniu capsules, tai-kang-ning, dynorphin, and l-tetrahydropalmatine. Analyzing the articles was difficult given the varied scoring methods they used to quantify opioid withdrawal symptoms and the small sample sizes in the trials. Most showed evidence that supported integrative medicine approaches for OWS, although the strength of evidence was limited because of sample sizes.

CONCLUSIONS

This review found evidence of multiple integrative medicine approaches for opioid withdrawal symptoms. Well-designed randomized controlled trials should assess the efficacy of integrative medicine for improvement in OWS.

Levo-tetrahydropalmatine attenuates the acquisition of fentanyl-induced conditioned place preference and the changes in ERK and CREB phosphorylation expression in mice

Levo-tetrahydropalmatine (L-THP) is the main active ingredient of Corydalis and Stephania and is widely used for its sedative, analgesic, and neuroleptic effects. Though L-THP is an antagonist of dopamine receptors and has been proven to be effective in treating drug addiction, its effect on fentanyl-induced reward learning still remains unclear. This experiment was designed to investigate the effects of L-THP on fentanyl-induced rewarding behavior through conditioned place preference (CPP) in mice. Western blot assays were used to dissect the accompanying changes in the phosphorylation of extracellular signal-regulated kinase (ERK) and cAMP response element binding protein (CREB) in related brain regions, including the hippocampus (Hip), caudate putamen (CPu), prefrontal cortex (PFC), and nucleus accumbens (NAc), which may mediate the effects of L-THP on fentanyl-induced CPP. The results revealed that fentanyl could induce CPP in mice at doses of 0.025 mg/kg, 0.05 mg/kg, 0.1 mg/kg, and 0.2 mg/kg, and L-THP could attenuate the acquisition of fentany-induced CPP at a dose of 10.0 mg/kg. The levels of p-ERK and p-CREB of the saline+fentanyl group (0.05 mg/kg) increased significantly in the Hip, NAc, and PFC compared to the saline+saline group. Furthermore, L-THP (10.0 mg/kg) co-administered with fentanyl during conditioning prevented the enhanced phosphorylation of ERK and CREB in the Hip, NAc, and PFC. Our research revealed that L-THP could suppress the rewarding properties of fentanyl-induced CPP, the inhibitory effect may be related to the suppression of ERK and CREB phosphorylation in the Hip, NAc, and PFC of mice. Thus, L-THP may have therapeutic potential for fentanyl addiction.

Can eastern wisdom resolve western epidemics? Traditional Chinese medicine therapies and the opioid crisis

The widespread use of opioids to treat chronic pain led to a nation-wide crisis in the United States. Tens of thousands of deaths annually occur mainly due to respiratory depression, the most dangerous side effect of opioids. Non-opioid drugs and non-pharmacological treatments without addictive potential are urgently required. Traditional Chinese medicine (TCM) is based on a completely different medical theory than academic Western medicine. The scientific basis of acupuncture and herbal treatments as main TCM practices has been considerably improved during the past two decades, and large meta-analyses with thousands of patients provide evidence for their efficacy. Furthermore, opinion leaders in the United States favor non-pharmacological techniques including TCM for pain management to fight the opioid crisis. We advocate TCM as therapeutic option without addictive potential and without life-threatening side effects (e.g., respiratory depression) to treat chronic pain patients suffering from opioid misuse. The evidence suggests that: (1) opioid misuse cannot be satisfactorily managed with standard medication; (2) opinion leaders in the United States favor to consider non-opioid and non-pharmacological treatment strategies including those from TCM to treat acute and chronic pain conditions; (3) large meta-analyses provide scientific evidence for the clinical activity of acupuncture and herbal TCM remedies in the treatment of chronic pain. Future clinical trials should demonstrate the safety of TCM treatments if combined with Western medical practices to exclude negative interactions between both modalities.

Inhibitory effect of ketoconazole, quinidine and 1-aminobenzotriazole on pharmacokinetics of l-tetrahydropalmatine and its metabolite in rats

l-tetrahydropalmatine (l-THP) is mainly metabolised by CYP450 enzymes.This study was to investigate the possible effect of co-administered CYP inhibitors on the pharmacokinetics of l-THP and its metabolites in rats.An established LC-MS/MS method has been applied for the evaluation of drug-drug interaction between l-THP and CYP inhibitors. Following the administration of CYP inhibitors, a single dose of l-THP (9 mg/kg) was orally administrated.With regard to l-THP, the AUC_0-48 were significantly increased by 4.3, 3.79, and 11.39 folds, and C_max were increased by 4.74, 3.64, and 2.76 folds in the ketoconazole group (KET), quinidine group (QD), and 1-aminobenzotriazole group (ABT), respectively. KET and QD both significantly increased the AUC_0-48 of 2-DM and 2-DM-Glu by 1.38 ∼ 2.43 times, while C_max was significantly decreased by 41.3 and 78.0% in the ABT group, respectively. The C_max of 3-DM was reduced by 51.38, 48.02, and 63.31% after pre-treatment with KET, QD, and ABT, respectively, and C_max of 3-DM-Glu decreased correspondingly by 29.6, 22.1, and 58.0%.Results indicated that CYP inhibitors could markedly influence the systemic level of l-THP and its metabolites. To guarantee the safe use of l-THP, attention should be paid when l-THP was co-administered with CYP inhibitors, particularly with CYP3A4 and 2D6 inhibitors.

Plants with Anti-Addictive Potential

Drug addiction is prevalent among individuals of modern society, being a major cause of disability and premature loss of life. Although the drug addiction have profound social, economical and health impact in the world population, its management remains a challenge as available pharmacological treatments remains ineffective for most people. The limited efficacy and adverse effects have led to a search for alternative therapies to treat drug addiction. In this context, natural products are an important source for new chemical substances with a potential therapeutic applicability. Therefore, this chapter will present data obtained after an extensive literature search regarding the use of medicinal plants as a pharmacological alternative for drug addiction treatment.

Neural bases for attenuation of morphine withdrawal by Heantos-4: role of l-tetrahydropalmatine

Severe withdrawal symptoms triggered by cessation of long-term opioid use deter many individuals from seeking treatment. Opioid substitution and α2-adrenergic agonists are the current standard of pharmacotherapy for opioid use disorder in western medicine; however, each is associated with significant complications. Heantos-4 is a non-opioid botanical formulation used to facilitate opioid detoxification in Vietnam. While ongoing clinical use continues to validate its safety and effectiveness, a mechanism of action accounting for these promising effects remains to be specified. Here, we assess the effects of Heantos-4 in a rat model of morphine-dependence and present evidence that alleviation of naloxone-precipitated somatic withdrawal signs is related to an upregulation of mesolimbic dopamine activity and a consequent reversal of a hypodopaminergic state in the nucleus accumbens, a brain region implicated in opioid withdrawal. A central dopaminergic mechanism is further supported by the identification of l-tetrahydropalmatine as a key active ingredient in Heantos-4, which crosses the blood–brain barrier and shows a therapeutic efficacy comparable to its parent formulation in attenuating withdrawal signs. The anti-hypodopaminergic effects of l-tetrahydropalmatine may be related to antagonism of the dopamine autoreceptor, thus constituting a plausible mechanism contributing to the effectiveness of Heantos-4 in facilitating opioid detoxification.

Advances in phytochemical and modern pharmacological research of Rhizoma Corydalis

ABSRACTContext: Rhizoma Corydalis (RC) is the dried tubers of Corydalis yanhusuo (Y. H. Chou and Chun C. Hsu) W. T. Wang ex Z. Y. Su and C. Y. Wu (Papaveraceae). Traditionally, RC is used to alleviate pain such as headache, abdominal pain, and epigastric pain. Modern medicine shows that it has analgesic, anti-arrhythmia, and other effects.Objective: We provided an overview of the phytochemical and pharmacological properties of RC as a foundation for its clinical application and further research and development of new drugs.Methods: We collected data of various phytochemical and pharmacological effects of RC from 1982 to 2019. To correlate with existing scientific evidence, we used Google Scholar and the journal databases Scopus, PubMed, and CNKI. 'Rhizoma Corydalis', 'phytochemistry', and 'pharmacological effects' were used as key words.Results: Currently, more than 100 chemical components have been isolated and identified from RC, among which alkaloid is the pimary active component of RC. Based on prior research, RC has antinociceptive, sedative, anti-epileptic, antidepressive and anti-anxiety, acetylcholinesterase inhibitory effect, drug abstinence, anti-arrhythmic, antimyocardial infarction, dilated coronary artery, cerebral ischaemia reperfusion (I/R) injury protection, antihypertensive, antithrombotic, antigastrointestinal ulcer, liver protection, antimicrobial, anti-inflammation, antiviral, and anticancer effects.Conclusions: RC is reported to be effective in treating a variety of diseases. Current pharmacological studies on RC mainly focus on the nervous, circulatory, digestive, and endocrine systems, as well as drug withdrawal. Although experimental data support the beneficial effects of this drug, its physiological activity remains a concern. Nonetheless, this review provides a foundation for future research.

Pharmacokinetic Effects of l-Tetrahydropalmatine on Ketamine in Rat Plasma by Ultraperformance Liquid Chromatography Tandem Mass Spectrometry

Male Sprague-Dawley rats (n = 18) were randomly divided into three groups: a saline group (20 mL/kg by gavage), a ketamine (KET) group (100 mg/kg by gavage), and a KET (the same routes and doses) combined with levo-tetrahydropalmatine (l-THP; 40 mg/kg by gavage) group (n = 6). Blood samples were acquired at different time points after drug administration. A simple and sensitive ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to determine the concentrations of KET and its metabolite, norketamine (NK), in rat plasma. Chromatographic separation was achieved using a BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with chlorpheniramine maleate (Chlor-Trimeton) as an internal standard (IS). The initial mobile phase consisted of acetonitrile–water with 0.1% methanoic acid (80 : 20, v/v). The multiple reaction monitoring (MRM) modes of m/z 238.1→m/z 179.1 for KET, m/z 224.1→m/z 207.1 for NK, and m/z 275→m/z 230 for Chlor-Trimeton (IS) were utilized to conduct a quantitative analysis. Calibration curves of KET and NK in rat plasma demonstrated good linearity in the range of 2.5–500 ng/mL (r > 0.9994), and the lower limit of quantification (LLOQ) was 2.5 ng/mL for both. Moreover, the intra- and interday precision relative standard deviation (RSD) of KET and NK were less than 4.31% and 6.53%, respectively. The accuracies (relative error) of KET and NK were below -1.41% and -6.07%, respectively. The extraction recoveries of KET and NK were more than 81.23 ± 3.45% and 80.42 ± 4.57%, respectively. This sensitive, rapid, and selective UPLC-MS/MS method was successfully applied to study the pharmacokinetic effects of l-THP on KET after gastric gavage. The results demonstrated that l-THP could increase the bioavailability of KET and promote the metabolism of KET. The results showed that l-THP has pharmacokinetics effects on KET in rat plasma.

Tetrahydroprotoberberines: A Novel Source of Pharmacotherapies for Substance Use Disorders?

Tetrahydroprotoberberines (THPBs) are a class of compounds that target both dopamine D1 and D2 families of receptors, making them attractive candidates for treating substance use disorder (SUD). The binding of some THPBs to serotonin and adrenergic receptors, in addition to dopamine receptors, gives rise to complex pharmacological profiles. Significant progress has been made over the last decade in examining these compounds for their therapeutic potential. Here, we evaluate recent discoveries relating to the neural mechanism and therapeutic effects of THPBs, focusing on compounds that have shown promise in animal models of SUD and preliminary clinical studies. Advancements in structure-activity relationship studies and in silico modeling of THPB binding to dopamine receptors have facilitated the synthesis of novel THPBs with enhanced therapeutic properties and provide insights regarding use of the THPB scaffold to serve as a template for innovative drug designs.

Role of natural products in mitigation of toxic effects of methamphetamine: A review of in vitro and in vivo studies

OBJECTIVE

Methamphetamine (METH) increases dopamine, norepinephrine and serotonin concentrations in the synaptic cleft, and induces hyperactivity. The current management of acute METH poisoning relies on supportive care and no specific antidote is available for treatment. The main objective of this review was to present the evidence for effectiveness of the herbal medicine in alleviating the adverse effects of METH abuse.

MATERIALS AND METHODS

Literature search was performed using the following electronic databases: MEDLINE, Scopus, PubMed and EMBASE.

RESULTS

Plant-derived natural products ginseng and sauchinone reduced METH-induced hyperactivity, conditioned place preference and neurological disorder. Garcinia kola decreased METH-induced hepatotoxicity, raised METH lethal dose, and restored the METH-impaired cognitive function. Repeated administration of baicalein resulted in attenuation of acute binge METH-induced amnesia via dopamine receptors. Activation of extracellular-regulated kinase in the hypothalamus by levo-tetrahydropalmatine facilitated the extinction of METH-induced conditioned place preference and reduced the hyperactivity. Other herbal medicine from various parts of the world were also discussed including hispidulin, silymarin, limonene, resveratrol, chlorogenic acid and barakol.

CONCLUSION

Based on the current study, some natural products such as ginseng and levo-tetrahydropalmatine are promising candidates to treat METH abuse and poisoning. However, clinical trials are needed to confirm these finding.

Protective and restorative effects of the traditional Chinese medicine Jitai tablet against methamphetamine-induced dopaminergic neurotoxicity

Background

Methamphetamine (METH) is a psychostimulant with high abuse liability that affects the monoamine neurotransmitter systems, particularly the dopamine system. Currently there are no effective medications for the treatment of METH abuse to restore METH-induced dopaminergic dysfunction. The Jitai tablet (JTT), a commercial traditional Chinese medicinal preparation, has been shown to modulate the dopaminergic function both in heroin addicts and in morphine-dependent rats. The purpose of this study was to investigate, in a rodent model, whether JTT can protect against METH-induced neurotoxicity, and/or restore METH-damaged dopaminergic function.

Methods

Immunohistochemical staining and/or autoradiography staining were used to detect tyrosine hydroxylase (TH) expression in the substantia nigra, and to examine the levels of dopamine transporter (DAT), dopamine D2 receptor (D2R) and TH levels in the striatum. Using a stereotyped behavior rating scale, we evaluated the inhibitory effect of JTT on METH-induced behavioral sensitization.

Results

Repeated METH administration induced obvious stereotyped behavior and neurotoxicity on the dopaminergic system. Pre-treatment with JTT significantly attenuated METH-induced stereotyped responses, and interdicted METH-induced changes in the levels of DAT, D2R and TH expression. Treatment with JTT after METH administration restored DAT, D2R and TH expression to normal levels.

Conclusions

Our results indicated that JTT protects against METH-induced neurotoxicity and restores the dopaminergic function, and thus might be a potential treatment for the dopaminergic deficits associated with METH abuse.

Development and validation of a high performance liquid chromatography quantification method of levo-tetrahydropalmatine and its metabolites in plasma and brain tissues: application to a pharmacokinetic study

Levo-tetrahydropalmatine (l-THP) is an alkaloid isolated from Chinese medicinal herbs of the Corydalis and Stephania genera. It has been used in China for more than 40 years mainly as an analgesic with sedative/hypnotic effects. Despite its extensive use, its metabolism has not been quantitatively studied, nor there a sensitive reliable bioanalytical method for its quantification simultaneously with its metabolites. As such, the objective of this study was to develop and validate a sensitive and selective HPLC method for simultaneous quantification of l-THP and its desmethyl metabolites l-corydalmine (l-CD) and l-corypalmine (l-CP) in rat plasma and brain tissues. Rat plasma and brain samples were processed by liquid-liquid extraction using ethyl acetate. Chromatographic separation was achieved on a reversed-phase Symmetry® C18 column (4.6 × 150 mm, 5 μm) at 25°C. The mobile phase consisted of acetonitrile-methanol-10 mm ammonium phosphate (pH 3) (10:30:60, v/v) and was used at a flow rate of 0.8 mL/min. The column eluent was monitored at excitation and emission wavelengths of 230 and 315 nm, respectively. The calibration curves were linear over the concentration range of 1-10,000 ng/mL. The intra- and interday reproducibility studies demonstrated accuracy and precision within the acceptance criteria of bioanalytical guidelines. The validated HPLC method was successfully applied to analyze samples from a pharmacokinetic study of l-THP in rats. Taken together, the developed method can be applied for bioanalysis of l-THP and its metabolites in rodents and potentially can be transferred for bioanalysis of human samples.

Antiaging and Anxiolytic Effects of Combinatory Formulas Based on Four Medicinal Herbs

The objective of the present study was to search for medicinal-herb combinations based on Radix Bupleurum chinense DC (“B”), Rhizoma Corydalis yanhusuo WT Wang (“Y”), Caulis Polygonum multiflorum Thunb (“P”), and Flos Albizia julibrissin Durazz (“A”) for antiaging, anxiolytic, and sedative effects. Application of the D-galactose induced accelerated-aging model employing male ICR mice showed that oral administration of some combinations of B, Y, P, and A significantly improved spatial memory in Y-maze test and reduced brain levels of tumor necrosis factor-α and interleukin-6 based on immunoassays and oxidative stress marker malondialdehyde, based on the thiobarbituric acid test, and the loss of whiskers, indicating antiaging and antineurodegeneration effects. In addition, some of the combinatory formulas induced anxiolysis measured using the elevated plus-maze test and/or sedative effects measured using the hole-board test. Over the range of dosages examined, all possible combinations of the four herbs were devoid of any significant side effects in the form of altered locomotor activity, decreased muscle coordination, or anterograde amnesia assessed using the photobeam and rotarod and step-through passive avoidance methods, respectively. The results suggest that various combinations of the B, Y, P, and A herbs could be useful as nonsedative, antiaging and/or antineurodegenerative agents, or anxiolytic agents.

Asymmetric total synthesis of tetrahydroprotoberberine derivatives and evaluation of their binding affinities at dopamine receptors

Cocaine addiction remains a serious challenge for clinical and medical research because there is no effective pharmacological treatment. l-THP, a natural product isolated from Corydalis yanhusuo W.T. Wang, is one of the most frequently used traditional herbs to treat drug addiction in China. Our laboratory first reported that its demethylated metabolites l-ICP, l-CD, and l-CP had high affinity at dopamine D1, D2, and D5 receptors. Here we report the chemical synthesis of these metabolites and other derivatives and their binding affinities at dopamine receptors. The synthesis of these bioactive metabolites will allow further in vivo study of their potential in treating cocaine addiction.

Simultaneous determination of l-tetrahydropalmatine and its active metabolites in rat plasma by a sensitive ultra-high-performance liquid chromatography with tandem mass spectrometry method and its application in a pharmacokinetic study

A sensitive and reliable ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous determination of l-tetrahydropalmatine (l-THP) and its active metabolites l-isocorypalmine (l-ICP) and L-corydalmine (l-CD) in rat plasma. The analytes were extracted by liquid-liquid extraction and separated on a Bonshell ASB C₁₈ column (2.1 × 100 mm; 2.7 μm; Agela) using acetonitrile-formic acid aqueous as mobile phase at a flow rate of 0.2 mL/min in gradient mode. The method was validated over the concentration range of 4.00-2500 ng/mL for l-THP, 0.400-250 ng/mL for l-ICP and 1.00-625 ng/mL for l-CD. Intra- and inter-day accuracy and precision were within the acceptable limits of <15% at all concentrations. Correlation coefficients (r) for the calibration curves were >0.99 for all analytes. The quantitative method was successfully applied for simultaneous determination of l-THP and its active metabolites in a pharmacokinetic study after oral administration with l-THP at a dose of 15 mg/kg to rats.

Levo-Tetrahydroberberrubine Produces Anxiolytic-Like Effects in Mice through the 5-HT1A Receptor

Tetrahydroprotoberberines (THPBs) are isoquinoline alkaloids isolated from the Chinese herb Corydalis yanhusuo. In the present study, we performed competitive binding assays to examine the binding of l-THBr to neurotransmitter receptors known to be involved in sedation, hypnosis and anxiety. Our results show that l-THBr does not interact with GABAergic receptors but has binding affinities for dopamine and serotonin receptors. In addition, cAMP and [³⁵S]GTPγS assays were used to determine the agonist or antagonist properties of l-THBr at dopamine (D₁, D₂) or serotonin (5-HT) receptors. Our results show that l-THBr displays D₁ and D₂ antagonist and 5-HT_1A agonist properties. Moreover, l-THBr-treated rodents exhibit anxiolytic-like effects in the light/dark box and elevated plus-maze tests, and the anxiolytic effect of l-THBr can be reduced by WAY-100635, a selective 5-HT_1A receptor antagonist. Our results suggest that l-THBr may produce potent anxiolytic-like effects mainly through serotonin receptors.

Traditional Chinese Medicine (TCM) Therapy

Traditional Chinese Medicine(TCM) has been utilized in China for more than 2,000 years, and it has been practiced in treatment of substance addiction and non-substance addictions. TCM have efficacy in the rehabilitation of abnormal physical problems induced by chronic drug use, including improving immune function, increasing working memory, and protecting against neurological disorders. Given that TCM is potentially effective in the prevention of relapse, it has been suggested that TCM may be the ideal choice in the future for the treatment of opiate addiction. This review examines the significance of effective Chinese herbs and prescriptions for Drug Addiction, Alcohol addiction and food addiction.

l-tetrahydropalmatine reduces nicotine self-administration and reinstatement in rats

BACKGROUND

The negative consequences of nicotine use are well known and documented, however, abstaining from nicotine use and achieving abstinence poses a major challenge for the majority of nicotine users trying to quit. l-Tetrahydropalmatine (l-THP), a compound extracted from the Chinese herb Corydalis, displayed utility in the treatment of cocaine and heroin addiction via reduction of drug-intake and relapse. The present study examined the effects of l-THP on abuse-related effects of nicotine.

METHODS

Self-administration and reinstatement testing was conducted. Rats trained to self-administer nicotine (0.03 mg/kg/injection) under a fixed-ratio 5 schedule (FR5) of reinforcement were pretreated with l-THP (3 or 5 mg/kg), varenicline (1 mg/kg), bupropion (40 mg/kg), or saline before daily 2-h sessions. Locomotor, food, and microdialysis assays were also conducted in separate rats.

RESULTS

l-THP significantly reduced nicotine self-administration (SA). l-THP's effect was more pronounced than the effect of varenicline and similar to the effect of bupropion. In reinstatement testing, animals were pretreated with the same compounds, challenged with nicotine (0.3 mg/kg, s.c.), and reintroduced to pre-extinction conditions. l-THP blocked reinstatement of nicotine seeking more effectively than either varenicline or bupropion. Locomotor data revealed that therapeutic doses of l-THP had no inhibitory effects on ambulatory ability and that l-THP (3 and 5 mg/kg) significantly blocked nicotine induced hyperactivity when administered before nicotine. In in-vivo microdialysis experiments, l-THP, varenicline, and bupropion alone elevated extracellular dopamine (DA) levels in the nucleus accumbens shell (nAcb).

CONCLUSIONS

Since l-THP reduces nicotine taking and blocks relapse it could be a useful alternative to varenicline and bupropion as a treatment for nicotine addiction.

Pharmacokinetics and Safety Assessment of l-Tetrahydropalmatine in Cocaine Users: A Randomized, Double-Blind, Placebo-Controlled Study

Cocaine use disorder (CUD) remains a significant public health challenge. l-Tetrahydropalmatine (l-THP), a well-tolerated and nonaddictive compound, shows promise for the management of CUD. Its pharmacologic profile includes blockade at dopamine and other monoamine receptors and attenuation of cocaine self-administration, reinstatement, and rewarding properties in rats. This study evaluated the safety of l-THP in human cocaine users and its influence on the safety and pharmacokinetics (PK) of cocaine. Twenty-four cocaine-using adult men were randomized to receive l-THP (30 mg twice a day orally) or placebo double-blind for 4 days, with an intranasal cocaine (40 mg) challenge on the fourth day. Safety and tolerability were evaluated using vital signs, ECG, clinical laboratory tests, and standardized self-report instruments. Peripheral venous blood was collected periodically and later assayed for l-THP and cocaine using highly sensitive and specific ultraperformance liquid chromatography-fluorescence detection (UPLC-FLD) methods. Twenty subjects completed the study, of whom 19 provided complete PK data. The short 3.5-day course of l-THP was safe and well tolerated and did not affect cocaine's PK or its acute cardiovascular effects. The cocaine AUC_0→∞ was 211.5 and 261.4 h·ng/mL, and the C_max was 83.3 and 104.5 ng/mL for the l-THP and placebo groups, respectively. In addition there were no significant differences in the number of side effects reported in each group (l-THP group 22 [48%], placebo group 24 [52%]) or vital signs including, heart rate, blood pressure, complete blood count, or ECG. These findings suggest that oral THP has promise for further development as a treatment for CUD.

Combination of Levo-Tetrahydropalmatine and Low Dose Naltrexone: A Promising Treatment for Prevention of Cocaine Relapse

Relapse to drug use is often cited as the major obstacle in overcoming a drug addiction. Whereas relapse can occur for a myriad of reasons, it is well established that complex neuroadaptations that occur over the course of addiction are major factors. Cocaine, as a potent dopamine transporter blocker, specifically induces alterations in the dopaminergic as well as other monoaminergic neurotransmissions, which lead to cocaine abuse and dependence. Evidence also suggests that adaptations in the endogenous opioids play important roles in pathophysiology of cocaine addiction. Following this evidence, we investigated a combination medication, levo-tetrahydropalmatine (l-THP) and low dose naltrexone (LDN), targeting primarily dopaminergic and endogenous opioid systems as a cocaine-relapse-prevention treatment. In the present study Wistar rats were used to assess the effects ofl-THP and LDN on cocaine self-administration, drug-seeking behavior during cocaine reinstatement, spontaneous locomotion, and effects on the endogenous opioid system. We determined that the combination ofl-THP and LDN reduces drug-seeking behavior during reinstatement more potently thanl-THP alone. Additionally, the combination ofl-THP and LDN attenuates the sedative locomotor effect induced byl-THP. Furthermore, we revealed that treatment with the combination ofl-THP and LDN has an upregulatory effect on both plasmaβ-endorphin and hypothalamic POMC that was not observed inl-THP-treated groups. These results suggest that the combination ofl-THP and LDN has great potential as an effective and well-tolerated medication for cocaine relapse prevention.

Longitudinal changes of dopamine transporters in heroin users during abstinence

RATIONALE

Chronic exposure to heroin results in decreased dopamine transporter levels. Jitai tablets, a traditional Chinese medicine, have been effective at increasing striatal dopamine transporter availability after 6 months of treatment. However, it remains unknown how long the heroin-induced impairment persists and whether dopamine transporter can be normalized following long-term abstinence or treatment.

OBJECTIVES

This study was to evaluate the time course of dopamine transporter changes in heroin users undergoing long-term abstinence and treatment with Jitai tablets for 1 year.

METHODS

Single-photon emission computed tomography using [(99m)Tc]TRODAT-1 was performed on 64 heroin users and 20 healthy subjects to assess striatal dopamine transporter availability at baseline, 3, 6, and 12 months. Heroin users were randomly assigned to treatment with either placebo or Jitai tablets. Depression and anxiety scores were measured before each imaging session.

RESULTS

Compared with healthy controls, significant reduction in dopamine transporter availability was found in heroin users at baseline in both the right (by ∼ 31.6%) and left striatum (by ∼ 33.2%). At 6 months, dopamine transporter availability was significantly higher in Jitai tablet-treated group than placebo group in the bilateral striatum (p < 0.01). At 12 months, dopamine transporter levels in both groups were upregulated substantially from baseline but still not recovered to normal levels in the left striatum (p < 0.05). Depression and anxiety scores significantly decreased at 3, 6, and 12 months (p < 0.05).

CONCLUSIONS

Our results confirmed that heroin abuse induces pronounced, long-term reduction in dopamine transporter. Treatment with Jitai tablets appears to stimulate recovery.

Effects of Jitai tablet, a traditional Chinese medicine, on spontaneous withdrawal symptoms and modulation of dopaminergic functions in morphine-dependent rats

Chronic opioid abuse can cause damage to dopamine neurons. However, there are currently no effective pharmacotherapies to reverse this damage, even though progress has been made in the development of therapeutic strategies for opioid dependence. The Jitai tablet (JTT) is a traditional Chinese medicine formulation most commonly used for opioid addiction treatment in China. In a morphine spontaneous withdrawal rat model we investigated the effects of JTT, either given before (pre-treatment) or after (post-treatment) morphine administration, on the dopamine system. Our study has shown the following: (1) pre- and post-treatment with JTT were effective at alleviating the wet dog shakes and episodes of writhing; (2) pre-treatment with JTT inhibited the morphine-induced decreases in dopamine transporter (DAT), dopamine D2 receptor (D2 R) and tyrosine hydroxylase (TH) levels in the striatum (p < 0.01, compared with morphine group) and maintained them at normal levels; and (3) post-treatment with JTT restored the densities of DAT, D2 R and TH in the striatum to normal levels (p < 0.01, compared with morphine group). These results support the notion that modulation of the dopamine system in the striatum may play a role for JTT's therapeutic effect on the alleviation of opioid withdrawal symptoms.

L-tetrahydropalmatine inhibits methamphetamine-induced locomotor activity via regulation of 5-HT neuronal activity and dopamine D3 receptor expression

Methamphetamine (METH) is a psychomotor stimulant that produces hyperlocomotion in rodents. l-tetrahydropalmatine (l-THP) is an active ingredient found in Corydalis ternata which has been used as a traditional herbal preparation in Asian countries for centuries, however, the effect of l-THP on METH-induced phenotypes largely unknown. In this study, to evaluate the effect of l-THP on METH-induced psychotropic effects, rats were pretreated with l-THP (10 and 15 mg/kg) before acute METH injection, following which the total distance the rats moved in an hour was measured. To clarify a possible mechanism underlying the effect of l-THP on METH-induced behavioral changes, dopamine receptor mRNA expression levels in the striatum of the rats was measured following the locomotor activity study. In addition, the effect of l-THP (10 and 15 mg/kg) on serotonergic (5-HTergic) neuronal pathway activation was studied by measurement of 5-HT (80 μg/10μl/mouse)-induced head twitch response (HTR) in mice. l-THP administration significantly inhibited both hyperlocomotion in rats and HTR in mice. l-THP inhibited climbing behavior-induced by dopaminergic (DAergic) neuronal activation in mice. Furthermore, l-THP attenuated the decrease in dopamine D3 receptor mRNA expression levels in the striatum of the rats induced by METH. These results suggest that l-THP can ameliorate behavioral phenotype induced by METH through regulation of 5-HT neuronal activity and dopamine D3 receptor expression.

Simultaneous determination of L-tetrahydropalmatine and cocaine in human plasma by simple UPLC-FLD method: application in clinical studies

Currently, there are no FDA approved medications for treatment of cocaine addiction underscoring the dire need to develop such a product. There is an accumulating body of evidence that l-tetrahydropalmatine (l-THP), a non-selective dopamine antagonist, can be used for the treatment of cocaine addiction. Indeed, the FDA recently approved its usage in a Phase I study in cocaine abusers and it was indispensable to develop a simple and sensitive method for the simultaneous determination of l-THP and cocaine in human plasma. We developed a UPLC-FLD method for quantitation of these molecules using an ACQUITY BEH C18 column (2.1 mm × 50mm, 1.7 μm) and a mobile phase that consisted of 10mM ammonium phosphate (pH=4.75), methanol, and acetonitrile (v:v:v, 78:16:6). Venlafaxine was used as the internal standard while hexane was used for the liquid-liquid extraction. The flow rate was 0.4 mL/min with fluorescence detection using an excitation wavelength of 230 nm and emission detection wavelength of 315 nm. This method was selective, linear and sensitive with a lower limit of quantification of 2.5 ng/mL for both cocaine and l-THP. The intra-day precision of cocaine and l-THP was <9.50% while the accuracy was <4.29%. The inter-day precision of cocaine and l-THP was <9.14%, and the accuracy was <12.49%. The recovery for cocaine and l-THP ranged from 43.95 to 50.02% and 54.65 to 58.31%, respectively. In comparison to forty reported cocaine quantitation methods this method is simple, sensitive and cost-effective and can be used for simultaneous quantitation of l-THP and cocaine. This method meets the FDA guidelines and can be used in current and future clinical studies.

L-isocorypalmine reduces behavioral sensitization and rewarding effects of cocaine in mice by acting on dopamine receptors

BACKGROUND

We previously reported isolation of l-isocorypalmine (l-ICP), a mono-demethylated analog of l-tetrahydropalmatine (l-THP), from the plant Corydalis yanhusuo. Here we characterized its in vitro pharmacological properties and examined its effects on cocaine-induced behaviors in mice.

METHODS

Receptor binding, cAMP and [(35)S]GTPγS assays were used to examine pharmacological actions of l-ICP in vitro. Effects of l-ICP on cocaine-induced locomotor hyperactivity and sensitization and conditioned place preference (CPP) in mice were investigated. HPLC was employed to analyze metabolites of l-ICP in mouse serum.

RESULTS

Among more than 40 targets screened, l-ICP and l-THP bound only to dopamine (DA) receptors. l-ICP was a high-affinity partial agonist of D1 and D5 receptors and a moderate-affinity antagonist of D2, D3 and D4 receptors, whereas l-THP bound to only D1 and D5 receptors, with lower affinities than l-ICP. At 10mg/kg (i.p.), l-ICP inhibited spontaneous locomotor activity for a shorter time than l-THP. Pretreatment with l-ICP reduced cocaine-induced locomotor hyperactivities. Administration of l-ICP before cocaine once a day for 5 days reduced cocaine-induced locomotor sensitization on days 5 and 13 after 7 days of withdrawal. Pretreatment with l-ICP before cocaine daily for 6 days blocked cocaine-induced CPP, while l-ICP itself did not cause preference or aversion. HPLC analysis showed that l-ICP was the main compound in mouse serum following i.p. injection of l-ICP.

CONCLUSIONS

l-ICP likely acts as a D1 partial agonist and a D2 antagonist to produce its in vivo effects and may be a promising agent for treatment of cocaine addiction.

Dopamine transporter availability in heroin-dependent subjects and controls: longitudinal changes during abstinence and the effects of Jitai tablets treatment

RATIONALE

Previous imaging studies have indicated that the levels of the dopamine transporter (DAT) are reduced in the brains of heroin users. However, whether these changes can be reversed by abstinence and/or treatment remains unclear.

OBJECTIVES

This study aims to investigate DAT availability in heroin users and changes in DAT availability after abstinence and treatment with the Jitai tablets, a traditional Chinese medicinal product that is approved for the treatment of opioid addiction.

METHODS

Single-photon emission computed tomography (SPECT) with [(99m)Tc] TRODAT-1 was performed on heroin-dependent patients (n = 64) and healthy controls (n = 15). The patients were randomly assigned to treatment with either placebo or the Jitai. All patients underwent SPECT imaging both at baseline and after 6 months of treatment. DAT availability was assessed in the caudate and putamen. Depression and anxiety were evaluated at baseline.

RESULTS

DAT availability remained at low levels during a 6-month period in the placebo-treated group but was increased (14-17 %) in the Jitai-treated group. The ratio of DAT availability at month 6 to that at baseline in the Jitai-treated group was significantly higher than that in the placebo-treated group in both the bilateral caudate and putamen. DAT uptake in the striatum was significantly correlated with daily heroin dose, years of heroin use, and depression.

CONCLUSIONS

These findings suggest that chronic heroin use induces long-lasting striatal DAT reductions. DAT availability remained unchanged during a 6-month period of abstinence. Treatment with Jitai appears to be effective at increasing striatal DAT availability.

A computational drug-target network for yuanhu zhitong prescription

Yuanhu Zhitong prescription (YZP) is a typical and relatively simple traditional Chinese medicine (TCM), widely used in the clinical treatment of headache, gastralgia, and dysmenorrhea. However, the underlying molecular mechanism of action of YZP is not clear. In this study, based on the previous chemical and metabolite analysis, a complex approach including the prediction of the structure of metabolite, high-throughput in silico screening, and network reconstruction and analysis was developed to obtain a computational drug-target network for YZP. This was followed by a functional and pathway analysis by ClueGO to determine some of the pharmacologic activities. Further, two new pharmacologic actions, antidepressant and antianxiety, of YZP were validated by animal experiments using zebrafish and mice models. The forced swimming test and the tail suspension test demonstrated that YZP at the doses of 4 mg/kg and 8 mg/kg had better antidepressive activity when compared with the control group. The anxiolytic activity experiment showed that YZP at the doses of 100 mg/L, 150 mg/L, and 200 mg/L had significant decrease in diving compared to controls. These results not only shed light on the better understanding of the molecular mechanisms of YZP for curing diseases, but also provide some evidence for exploring the classic TCM formulas for new clinical application.

Methadone at tapered doses for the management of opioid withdrawal

BACKGROUND

The evidence of tapered methadone's efficacy in managing opioid withdrawal has been systematically evaluated in the previous version of this review that needs to be updated

OBJECTIVES

To evaluate the effectiveness of tapered methadone compared with other detoxification treatments and placebo in managing opioid withdrawal on completion of detoxification and relapse rate.

SEARCH METHODS

We searched: Cochrane Central Register of Controlled Trials (The Cochrane Library 2012, Issue 4), PubMed (January 1966 to May 2012), EMBASE (January 1988 to May 2012), CINAHL (2003- December 2007), PsycINFO (January 1985 to December 2004), reference lists of articles.

SELECTION CRITERIA

All randomised controlled trials that focused on the use of tapered methadone versus all other pharmacological detoxification treatments or placebo for the treatment of opiate withdrawal.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the included studies. Any doubts about how to rate the studies were resolved by discussion with a third review author. Study quality was assessed according to the criteria indicated in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Twenty-three trials involving 2467 people were included. Comparing methadone versus any other pharmacological treatment, we observed no clinical difference between the two treatments in terms of completion of treatment, 16 studies 1381 participants, risk ratio (RR) 1.08 (95% confidence interval (CI) 0.97 to 1.21); number of participants abstinent at follow-up, three studies, 386 participants RR 0.98 (95% CI 0.70 to 1.37); degree of discomfort for withdrawal symptoms and adverse events, although it was impossible to pool data for the last two outcomes. These results were confirmed also when we considered the single comparisons: methadone with: adrenergic agonists (11 studies), other opioid agonists (eight studies), anxiolytic (two studies), paiduyangsheng (one study). Comparing methadone with placebo (two studies) more severe withdrawal and more drop-outs were found in the placebo group. The results indicate that the medications used in the included studies are similar in terms of overall effectiveness, although symptoms experienced by participants differed according to the medication used and the program adopted.

AUTHORS' CONCLUSIONS

Data from literature are hardly comparable; programs vary widely with regard to the assessment of outcome measures, impairing the application of meta-analysis. The studies included in this review confirm that slow tapering with temporary substitution of long- acting opioids, can reduce withdrawal severity. Nevertheless, the majority of patients relapsed to heroin use.

Levo-tetrahydropalmatine decreases ethanol drinking and antagonizes dopamine D2 receptor-mediated signaling in the mouse dorsal striatum

An herb derived compound, levo-tetrahydropalmatine (L-THP), attenuates self-administration of cocaine and opiates in rodents. Since L-THP mainly antagonizes dopamine D2 receptors (D2R) in the brain, it is likely to regulate other addictive behaviors as well. Here, we examined whether L-THP regulates ethanol drinking in C57BL/6J mice using a two-bottle choice drinking experiment. L-THP treated mice consumed less ethanol compared to vehicle-treated mice during the 15% ethanol drinking session while water consumption remained similar between each group. We then examined the molecular basis underlying the pharmacological effect of L-THP in mice. Our results indicated that a single injection of L-THP increased active phosphorylated forms of PKA, AKT and ERK in the caudate-putamen (CPu), but not in the nucleus accumbens (NAc), of alcohol naïve mice. Interestingly, we found that systematic treatment with L-THP for 4 consecutive days while mice were drinking 15% ethanol increased pPKA levels in the CPu, but not in the NAc. In contrast to the effect of acute L-THP treatment, no differences were detected for pAKT or pERK in either striatal regions. Together, our findings suggest that reduction of ethanol drinking by L-THP treatment is possibly correlated with D2R-mediated PKA signaling in the CPu.

l-tetrahydropalamatine: a potential new medication for the treatment of cocaine addiction

Levo-tetrahydropalmatine (l-THP) is an active constituent of herbal preparations containing plant species of the genera Stephania and Corydalis and has been approved and used in China for a number of clinical indications under the drug name Rotundine. The pharmacological profile of l-THP, which includes antagonism of dopamine D1 and D2 receptors and actions at dopamine D3, α adrenergic and serotonin receptors, suggests that it may have utility for treating cocaine addiction. In this review, we provide an overview of the pharmacological properties of l-THP and the evidence supporting its development as an anti-addiction medication. The results of preclinical work demonstrating that l-THP attenuates cocaine's reinforcing/rewarding effects and reinstatement in rat models of cocaine relapse are summarized, and the outcomes of studies demonstrating efficacy in human addicts are described. Finally, an overview of the safety profile of l-THP is provided and challenges associated with US FDA approval of l-THP are discussed.