The role of heterodimers formed by histamine H3 receptors and dopamine D1 receptors on the methamphetamine-induced conditioned place preference.

RATIONALE: The rewarding effect of Methamphetamine (METH) is commonly believed to play an important role in METH use disorder. The altered expression of dopamine D1 receptor (D1R) has been suggested to be essential to the rewarding effect of METH. Notably, D1R could interact with histamine H3 receptors (H3R) by forming a H3R-D1R heteromer (H3R-D1R). OBJECTIVES: This study was designed to specifically investigate the involvement of H3R-D1R in the rewarding effect of METH. METHODS: C57BL/6 mice were treated with intraperitoneal injections of a selective H3R antagonist (Thioperamide, THIO; 20 mg/kg), an H1R antagonist (Pyrilamine, PYRI; 10 mg/kg), or microinjections of cytomegalovirus (CMV)-transmembrane domain 5 (TM5) into the nucleus accumbens (NAc). The animal model of Conditioned Place Preference (CPP) was applied to determine the impact of H3R-D1R on the rewarding effect of METH. RESULTS: METH resulted in a significant preference for the drug-associated chamber, in conjunction with increased H3R and decreased D1R expression in both NAc and the ventral tegmental area (VTA). THIO significantly attenuated the rewarding effect of METH, accompanied by decreased H3R and increased D1R expression. In contrast, pyrilamine failed to produce the similar effects. Moreover, the inhibitory effect of THIO on METH-induced CPP was reversed by SKF38393, a D1R agonist. Furthermore, SCH23390, a D1R antagonist, counteracted the ameliorative effect of SKF38393 on THIO. Co-immunoprecipitation (CO-IP) experiments further demonstrated the specific interaction between H3R and D1R in METH CPP mice. The rewarding effect of METH was also significantly blocked by the interruption of CMV-transmembrane domain 5 (TM5), but not CMV-transmembrane domain 7 (TM7) in NAc. CONCLUSION: These results suggest that modulating the activity of H3R-D1R complex holds promise for regulating METH use disorder and serves as a potential drug target for its treatment.

Inhibition of GSDMD-dependent pyroptosis decreased methamphetamine self-administration in rats.

It is widely believed that the activation of the central dopamine (DA) system is crucial to the rewarding effects of methamphetamine (METH) and to the behavioral outcomes of METH use disorder. It was reported that METH exposure induced gasdermin D (GSDMD)-dependent pyroptosis in rats. The membrane pore formation caused by METH-induced pyroptosis may also contribute to the overflow of DA into the extracellular space and subsequently increase the DA levels in the brain. The present study firstly investigated whether the membrane pore information induced by GSDMD-dependent pyroptosis was associated with the increased DA levels in the ventral tegmental area (VAT) and nucleus accumbens (NAc) of rats self-administering METH and SY-SH5Y cells treated by METH. Subsequently, the effect of pore formation blockade or genetic inhibition of GSDMD on the reinforcing and motivational effect of METH was determined in rats, using the animal model of METH self-administration (SA). METH exposure significantly increased the activity of NLRP1/Cas-1/GSDMD pathway and the presence of pyroptosis, accompanied by the significantly increased DA levels in VTA and NAc. Moreover, intraperitoneal injections of disulfiram (DSF) or microinjection of rAAV-shGSDMD into VTA/NAc significantly reduced the reinforcing and motivational effect of METH, accompanied by the decreased level of DA in VTA and NAc. The results provided novel evidence that METH-induced pyroptosis could increase DA release in VTA and NAc via the NLRP1/Cas-1/GSDMD pathway. Additionally, membrane pores or GSDMD blockade could significantly reduce the reinforcing and motivational effect of METH. In conclusion, blocking GSDMD and membrane pore formation could be a promising potential target for the development of agents to treat METH use disorder.

The neuroprotective effect of LCZ696 on methamphetamine-induced cognitive impairment in mice.

OBJECTIVE: Methamphetamine (METH) exposure commonly causes cognitive impairment. An angiotensin II receptor/neprilysin inhibitor (ARNI), LCZ696 has been demonstrated to inhibit inflammation, oxidative stress and apoptosis. The present study was designed to examine the effect of LCZ696 on METH-induced cognitive impairment and the underlying mechanism. METHODS: Following daily treatment of either saline or METH (5 mg/kg) for 5 consecutive days, the cognitive function was tested using the Y-maze and the Novel Object Recognition (NOR) in Experiment 1. In Experiment 2, mice were initially treated with saline or LCZ696 (60 mg/kg) for 9 consecutive days, followed by LCZ696, METH or saline for 5 days. Cognitive testing was carried out as Experiment 1. In Experiment 3, SH-SY5Y cells were treated with either METH (2.5 Mm) or ddH2O for 12 h. The apoptosis and reactive oxygen species (ROS) level of SH-SY5Y were examined. In Experiment 4, SH-SY5Y cells were pretreated with either ddH2O or LCZ696 (70um) for 30 min, followed by ddH2O or METH treatment for 12 h. Nrf2 and HO-1 protein expression was examined in the ventral tegemental area (VTA) of all the animals and SH-SY5Y cells. RESULTS: LCZ696 significantly improved METH-induced cognitive impairment, in conjunction with decreased apoptosis and ROS levels in VTA of METH-treated mice and SH-SY5Y cells. METH significantly decreased Nrf2 and HO-1 protein expression in VTA of mice and SH-SY5Y cells, which was reversed by LCZ696 treatment. CONCLUSION: LCZ696 yields a neuroprotective effect against METH-induced cognitive dysfunction via the Nrf2/HO-1 signaling pathway.

EGCG attenuates METH self-administration and reinstatement of METH seeking in mice.

Methamphetamine (METH) use disorder is a chronic, relapsing disorder and involves frequent failures of self-control of drug seeking and taking. Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenolic compounds of green tea, which has shown great therapeutic effectiveness in neurological disorders. However, it is still unknown whether and how EGCG affects METH seeking behaviour. Here, we show nanostructured EGCG/ascorbic acid nanoparticles (EGCG/AA NPs) dose-dependently reduced METH self-administration (SA) under fixed-ratio 1 (FR1) and progressive ratio (PR) reinforcement schedules in mice and shifted METH dose-response curves downward. Furthermore, EGCG/AA NPs decreased drug- and cue-induced METH seeking. In addition, we found that METH SA led to a decrease in inhibitory postsynaptic currents (IPSCs) and increase in the AMPAR/NMDAR ratio and excitation/inhibition (E/I) ratio in ex vivo midbrain slices from ventral tegmental area (VTA) dopamine neurons. EGCG/AA NPs enhanced Gamma-aminobutyric acid (GABA)ergic inhibition and normalized the E/I ratio. EGCG restored the balance between excitation and inhibition in VTA dopamine neurons, which may contribute to the attenuation of METH SA. These findings indicate that EGCG is a promising pharmacotherapy for METH use disorder.

An unconventional cancer-promoting function of methamphetamine in hepatocellular carcinoma.

For the past decade, the prevalence and mortality of methamphetamine (METH) use have doubled, suggesting that METH use could be the next substance use crisis worldwide. Ingested METH is transformed into other products in the liver, a major metabolic organ. Studies have revealed that METH causes deleterious inflammatory response, oxidative stress, and extensive DNA damage. These pathological damages are driving factors of hepatocellular carcinoma (HCC). Nonetheless, the potential role of METH in HCC and the underlying mechanisms remain unknown. Herein, we found a higher HCC incidence in METH abusers. METH promoted cellular proliferation, migration, and invasion in two human-derived HCC cells. Consistently, METH uptake promoted HCC progression in a xenograft mouse model. Mechanistically, METH exposure induced ROS production, which activated the Ras/MEK/ERK signaling pathway. Clearance of ROS by NAC suppressed METH-induced activation of Ras/ERK1/2 pathways, leading to arrest of HCC xenograft formation in nude mice. To the best of our knowledge, this is the first study to substantiate that METH promotes HCC progression and inhibition of ROS may reverse this process.

Neuroprotective effect of histamine H3 receptor blockade on methamphetamine-induced cognitive impairment in mice.

OBJECTIVE: Methamphetamine (METH) exposure is commonly believed to result in cognitive impairment. Histamine H3 receptor (H3R) antagonists reportedly have potential applications for treating cognitive impairment accompanied by various neuropsychiatric disorders. The present study aimed to investigate the effect of H3R blockade by Thioperamide (THIO) on METH-induced cognitive impairment and the underlying mechanism. METHODS: In Experiment 1, C57BL/6 mice received daily injections of saline or 5 mg/kg METH for 5 consecutive days. The Novel Object Recognition (NOR) and Morris water maze (MWM) tasks were used to assess cognitive functions of mice. H3R protein expression and apoptosis were subsequently measured in the hippocampus. In Experiment 2, HT22 cells were first treated with ddH2O or 3 mM METH. The cell survival rate and H3R protein level were subsequently assessed. In Experiment 3, the animals were first treated with saline or 20 mg/kg THIO for 7 days, followed by co-administration of either saline or 5 mg/kg METH for an additional 5 days. The remaining experiments were carried out in the same manner as Experiment 1. In Experiment 4, HT22 cells were pretreated with either ddH2O or 5 mM THIO for 2 h, followed by ddH2O or 3 mM METH treatment for an additional 12 h. The remaining experiments were carried out in the same manner as Experiment 2. In Experiment 5, the changes in MEK1/2, p-MEK1/2, ERK1/2 and p-ERK1/2 protein levels were examined in the hippocampus of all mice from Experiment 3 and HT22 cells from Experiment 4. RESULTS: METH-treated mice showed significantly worsened NOR and MWM performance, along with markably hippocampal apoptosis. A significantly lower cell survival rate was observed in METH-treated HT22 cells. Increased levels of H3R protein were found in both METH-treated mice and HT22 cells. THIO significantly improved METH-induced cognitive impairment in mice and toxicity in HT22 cells. METH significantly increased the level of p-MEK1/2 and p-ERK1/2 proteins in the hippocampus of mice and HT22 cells, which was reversed by THIO pretreatment. CONCLUSION: Our findings reveal that H3R blockade by THIO yields a neuroprotective effect against METH-induced cognitive impairment in mice and toxicity in HT22 cells via the raf-MEK-ERK signaling pathway.

The Significance of NLRP Inflammasome in Neuropsychiatric Disorders.

The NLRP inflammasome is a multi-protein complex which mainly consists of the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain. Its activation is linked to microglial-mediated neuroinflammation and partial neuronal degeneration. Many neuropsychiatric illnesses have increased inflammatory responses as both a primary cause and a defining feature. The NLRP inflammasome inhibition delays the progression and alleviates the deteriorating effects of neuroinflammation on several neuropsychiatric disorders. Evidence on the central effects of the NLRP inflammasome potentially provides the scientific base of a promising drug target for the treatment of neuropsychiatric disorders. This review elucidates the classification, composition, and functions of the NLRP inflammasomes. It also explores the underlying mechanisms of NLRP inflammasome activation and its divergent role in neuropsychiatric disorders, including Alzheimer's disease, Huntington's disease, Parkinson's disease, depression, drug use disorders, and anxiety. Furthermore, we explore the treatment potential of the NLRP inflammasome inhibitors against these disorders.

[Experimental factors affecting in vitro recovery of puerarin in microdialysis].

OBJECTIVE: : To analyze experimental factors affecting in vitro recovery of puerarin in microdialysis. METHODS: : Puerarin concentration in microdialysate samples was determined by high performance liquid chromatography. The methods of direct dialysis, retrodialysis and the zero-net flux were used to calculate in vitro recovery, respectively. The effects of perfusate composition, the analyte concentration, perfusate flow rate, medium temperature and stir rates of the dialysis medium on recovery were investigated. RESULTS: : There were significant differences in the recovery values among direct dialysis, retrodialysis and zero-net flux methods. The recovery for 0.9% NaCl solution, Ringer's solution, PBS and anticoagulant dextrose solution as perfusate fluid were (71.25±2.36)%,(73.48±1.41)%,(68.50±2.43)% and (74.98±1.16)%, respectively. The composition of perfusate fluid had significant influence on the recovery(P<0.01). At the same flow rate, recovery was independent of the analyte concentration. At the same concentration, the recovery was decrease with the increasing flow rate in an exponential relationship. The recovery increased with the raising temperature and stir rate of the dialysis medium, and the recovery remained stable when the stir rate reached above 200 rpm. CONCLUSIONS: : A study method for in vitro recovery of puerarin in microdialysis has been established, and the recovery of puerarin is affected by calculating methods, perfusate fluids, flow rate, medium temperature and stir rate, but not affected by analyte concentrations.

A simple blood microdialysis in freely-moving rats for pharmacokinetic-pharmacodynamic modeling study of Shengmai injection with simultaneous determination of drug concentrations and efficacy levels in dialysate.

Microdialysis is a powerful in vivo sampling technique for pharmacokinetic-pharmacodynamic (PK-PD) modeling of drugs in pre-clinical and clinical studies. However, the noticeable limitations of previous studies using microdialysis were that animals anesthesia in the whole experiment and the combination of microdialysis and blood sampling for drug and (or) effect detection, which can obviously influence PK and PD behavior of drugs. In this study, a simple blood microdialysis sampling system in freely-moving rats was established for simultaneous study of PK and PD of Shengmai injection (SMI) effect on inducing real-time nitric oxide (NO) release on isoproterenol (ISO) induced myocardial ischemia rats. The LC-MS/MS and HPLC with fluorescence detection (HPLC-FLD) methods were developed to determine ginsenside Rg1, Rg2, Re, Rf, Rb1, Rd and Rc, the main effective components of SMI, and NOx-, the main oxidation products of NO, in dialysates respectively. Through simultaneous determination of drug concentrations and NO efficacy levels in dialysate, the developed methods were successfully applied to set up concentration-time and effect-time profiles followed by PK-PD modeling of SMI effect on inducing NO release after intravenous administration of 10.8 mL kg-1 SMI in myocardial ischemia rats. The PK-PD modeling characterized the dose-effect relationships of SMI and behaved good prediction ability. The established blood microdialysis in freely-moving rats is an appealing technology for rational PK-PD studies when selecting suitable blood endogenous micromolecule as effect marker.

[Application progress of proteomic in pharmacological study of Chinese medicinal formulae].

Chinese medicinal formulae are the important means of clinical treatment in traditional Chinese medicine. It is urgent to use modern advanced scientific and technological means to reveal the complicated mechanism of Chinese medicinal formulae because they have the function characteristics of multiple components, multiple targets and integrated regulation. The systematic and comprehensive research model of proteomic is in line with the function characteristics of Chinese medicinal formulae, and proteomic has been widely used in the study of pharmacological mechanism of Chinese medicinal formulae. The recent applications of proteomic in pharmacological study of Chinese medicinal formulae in anti-cardiovascular and cerebrovascular diseases, anti-liver disease, antidiabetic, anticancer, anti-rheumatoid arthritis and other diseases were reviewed in this paper, and then the future development direction of proteomic in pharmacological study of Chinese medicinal formulae was put forward. This review is to provide the ideas and method for proteomic research on function mechanism of Chinese medicinal formulae.

[Research progress of pharmacokinetics and pharmacodynamics of total glucosides of peony in hepatoprotective effects].

Total glucosides of peony (TGP), containing the effective components of paeoniflorin (Pae), albiflorin (Alb) and so on, are effective parts of Radix Paeoniae Alba. And it possesses extensive pharmacological actions, one of which is hepatoprotective effect. In recent years, abundant of pharmacokinetics and pharmacodynamics research of TGP in hepatoprotective effects have been performed. However, the relative medicine of TGP in hepatoprotective effect has not been developed for clinical application. In order to provide reference for the development and rational clinical application of TGP, the research progresses of pharmacokinetics and pharmacodynamics of TGP in hepatoprotective effect were summarized in this paper. Pharmacokinetics research has clarified the process of absorption, distribution, metabolism and excretion of TGP in vivo, and liver injury disease can significantly influence its metabolic processes. Pharmacodynamics studies suggested that TGP can protect against acute liver injury, non-alcoholic fatty liver diseases (NAFLD), chronic liver fibrosis and liver cancer. However, the action mechanism and in vivo process about hepatoprotective effects of TGP have not been clearly revealed. How liver injury influences the metabolism of TGP and its integrated regulation through multiple targets need to be further studied. The combined pharmacokinetics and pharmacodynamics studies should be performed in favour of medicine development and clinical application of TGP in hepatoprotective effects.