Monoclonal antibody targeting mu-opioid receptor attenuates morphine tolerance via enhancing morphine-induced receptor endocytosis

Morphine is a frequently used analgesic that activates the mu-opioid receptor(MOR),which has prominent side effects of tolerance.Although the inefficiency of morphine in inducing the endocytosis of MOR underlies the development of morphine tolerance,currently,there is no effective therapy to treat morphine tolerance.In the current study,we aimed to develop a monoclonal antibody(mAb)precisely targeting MOR and to determine its therapeutic efficacy on morphine tolerance and the underlying molecular mechanisms.We successfully prepared a mAb targeting MOR,named 3A5C7,by hybridoma technique using a strategy of deoxyribonucleic acid immunization combined with cell immunization,and identified it as an immunoglobulin G mAb with high specificity and affinity for MOR and binding ability to antigens with spatial conformation.Treatment of two cell lines,HEK293T and SH-SY5Y,with 3A5C7 enhanced morphine-induced MOR endocytosis via a G protein-coupled receptor kinase 2(GRK2)/b-arrestin2-dependent mechanism,as demonstrated by immunofluorescence staining,flow cytometry,Western blotting,coimmunoprecipitation,and small interfering ribonucleic acid(siRNA)-based knockdown.This mAb also allowed MOR recycling from cytoplasm to plasma membrane and attenuated morphine-induced phosphorylation of MOR.We established an in vitro morphine tolerance model using differentiated SH-SY5Y cells induced by retinoic acid.Western blot,enzyme-linked immunosorbent assays,and siRNA-based knockdown revealed that 3A5C7 mAb diminished hyperactivation of adenylate cyclase,the in vitro biomarker of morphine tolerance,via the GRK2/b-arrestin2 pathway.Furthermore,in vivo hotplate test demonstrated that chronic intrathecal administration of 3A5C7 significantly alleviated morphine tolerance in mice,and withdrawal jumping test revealed that both chronic and acute 3A5C7 intrathecal administration attenuated morphine dependence.Finally,intrathecal electroporation of silencing short hairpin RNA illustrated that the in vivo anti-tolerance and anti-dependence efficacy of 3A5C7 was mediated by enhanced morphine-induced MOR endocytosis via GRK2/b-arrestin2 pathway.Collectively,our study provided a therapeutic mAb,3A5C7,targeting MOR to treat morphine tolerance,mediated by enhancing morphine-induced MOR endocytosis.The mAb 3A5C7 demonstrates promising translational value to treat clinical morphine tolerance.

Nitroester drug's effects and their antagonistic effects against morphine on human sphincter of Oddi motility

AIM: To evaluate the effects of nitroester drugs on human sphincter of Oddi (SO) motility and their antagonistic effects against morphine which shows excitatory effect on Oddi's sphincter motility.METHODS: The effects of these drugs on SO were evaluated by means of choledochofiberoscopy manometry.A total of 67 patients having T-tubes after cholecystectomy and choledochotomy were involved in the study, they were randomly divided into glyceryl trinitrate (GTN) group,isosorbide dinitrate (ISDN) group, pentaerythritol tetranitrate (PTN) group, morphine associated with GTN group, morphine associated with ISDN group and morphine associated with PTN group. Basal pressure of Oddi's sphincter (BPOS), amplitude of phasic contractions (SOCA), frequency of phasic contractions (SOF), duration of phasic contractions (SOD), duodenal pressure (DP) and common bile duct pressure (CBDP) were scored and analyzed. Morphine was given intramuscularly while nitroester drugs were applied sublingually.RESULTS: BPOS and SOCA decreased significantly after administration of ISDN and GTN, BPOS reduced from 10.95±7.49 mmHg to 5.92±4.04 mmHg (P＜0.05) evidently after application of PTN. BPOS increased from 7.37±5.58mmHg to 16.60±13.87 mmHg, SOCA increased from 54.09±38.37 mmHg to 100.70±43.51 mmHg, SOF increased from 7.15±3.20 mmHg to 10.38±2.93 mmHg and CBDP increased 3.75±1.95 mmHg to 10.49±8.21 mmHg (P＜0.01)evidently after injection of morphine. After associated application of ISDN and GTN, the four indications above decreased obviously. As for application associated with PTN,SOCA and SOF decreased separately from 100.64±44.99mmHg to 66.17±35.88 mmHg and from 10.70±2.76 mmHg to 9.04±1.71 mmHg (P＜0.05) markedly.CONCLUSION: The regular dose of GTN, ISDN and PTN showed inhibitory effect on SO motility, morphine showed excitatory effect on SO while GTN, ISDN and PTN could antagonize the effect of morphine. Among the three nitroester drugs, the effect of ISDN on SO was most significant.

Relative efficacy of some prokinetic drugs in morphine-induced gastrointestinal transit delay in mice

AIM: To study the relative efficacy of cisapride,metoclopramide, domperidone, erythromycin and mosapride on gastric emptying (GE) and small intestinal transit (SIT)in morphine treated mice.METHODS: Phenol red marker meal was employed to estimate GE and SIT in Swiss albino mice of either sex. The groups included were control, morphine 1 mg/kg (s.c. 15min before test meal) alone or with (45 min before test meal p.o.) cisapride 10 mg/kg, metoclopramide 20 mg/kg,domperidone 20 mg/kg, erythromycin 6 mg/kg and mosapride 20 mg/kg.RESULTS: Cisapride, metoclopramide and mosapride were effective in enhancing gastric emptying significantly (P＜0.001)whereas other prokinetic agents failed to do so in normal mice. Metoclopramide completely reversed morphine induced delay in gastric emptying followed by mosapride.Metoclopramide alone was effective when given to normal mice in increasing the SIT. Cisapride, though it did not show any significant effect on SIT in normal mice, was able to reverse morphine induced delay in SIT significantly (P＜0.001)followed by metoclopramide and mosapride.CONCLUSION: Metoclopramide and cisapride are most effective in reversing morphine-induced delay in gastric emptying and small intestinal transit in mice respectively.

Brain-derived neurotrophic factor and Bcl-2 expression in rat brain areas following chronic morphine treatment

The ventral tegmental area and the locus coeruleus are associated with psychological and physical dependence of opioid addiction. To date, very little is known about brain-derived neurotrophic factor （BDNF） and Bcl-2 gene and protein changes following morphine addiction. The present study utilized immunohistochemistry and in situ hybridization techniques, which revealed that there were increased BDNF levels, but decreased Bcl-2 levels in the prefrontal cortex, locus coeruleus, hippocampus, and the ventral tegmental area during morphine-dependence formation and abstinence. However, the levels of BDNF remained unchanged, and Bcl-2 expression was increased in the nucleus accumbens. These results showed that BDNF and Bcl-2 are involved in the development of morphine dependence, and precipitation of abstinence syndrome.

Circular RNA expression alterations are involved in incubation of morphine craving

OBJECTIVE Cue-induced drug craving progressively increase after prolong abstinence in animal and human beings.A behavioral phenomenon termed incubation of drug craving is considered as a key reason for drug relapse,but the transcriptional mechanisms that contribute to this incubation are unknown.It has been demonstrated that circular RNAs(circR NAs),act as miR NA sponges,play important roles in the regulation of gene expression and the pathogenesis of disease.The present study aims to explore the transcriptional profiles associated with incubation of morphine craving in nucleus accumbens(NAc),an important brain area previously implicated in drug seeking.METHODS The animal model of the incubation of drug craving was induced by CPP paradigms with six morphine(5 mg·kg-1) injections and 14 d drug abstinence in mice.The brain tissues of NAc were collected after the behavioral tests for circRNA-sequencing by Illumina Hiseq X sequencer.We identified differentially expressed genes(DEGs) by qRT-PCR and used bioinformatics methods for further function analysis.RESULTS The progressive increase of CPP scores during the 14 d drug abstinence indicated the establishment of animal model.The data of circRNA-sequencing reported that 16 circRNAs were significantly altered after 28 d drug abstinence in NAc of morphine treated mice(FC≥2 and P<0.05).Among those circRNAs,9 were significantly up-regulated,while 7 were down-regulated.Furthermore,we subsequently tested circRNAs expression using quantitative real-time PCR,and the consistent data were obtained.The results of KEGG pathway analysis indicated that these genes were enriched for several biological processes,including RNA transport,protein ubiquitination and histone methylation,etc.CONCLUSION These findings provide a unique resource of gene expression data for future studies examining transcriptional mechanisms in NAc that mediate opioids seeking after prolonged withdrawal.

Changes in neurosteroid levels and steroidogenic enzyme expression in the brain of morphine dependent and withdrawing rats

BACKGROUND： Studies have demonstrated that exogenous neurosteroid treatment prevents the development of morphine tolerance and dependence, and attenuates abstinence behavior in mice. However, there are few studies on whether the levels of endogenous neurosteroids can be changed by morphine dependence and withdrawal. OBJECTIVE： To investigate the levels of various neurosteroids in rat brain following morphine dependence and withdrawal. To evaluate the expressions of steroidogenic enzyme mRNAs and proteins. To identify the relationship between neurosteroids and morphine dependence at the whole animal behavior, neural biochemistry, and molecular levels. DESIGN, TIME AND SETTING： A randomized, controlled study. Experiments were performed at the Department of Pharmacology of Hebei Medical University and Department of Pharmacology of Beathune International Peace Hospital, China, from June 2004 to October 2007. MATERIALS： Morphine hydrochloride injection （Shenyang First Pharmaceutical Factory, China）, naloxone hydrochloride （Hunan Yiqiao Pharmaceutical Co., China） and a gas chromatography-mass spectrometry system （Agilent, CA, USA） were used in this study. METHODS： Healthy adult Sprague Dawley rats were randomly divided into three groups： a morphine dependence group, morphine withdrawal group and control group （n = 20）. The rats in the morphine dependence and morphine withdrawal groups were given increasing doses of morphine （5, 10, 15, 20, 30, 40 and 50 mg/kg, intraperitoneal） to create morphine dependence. The rats in the morphine withdrawal group were injected with 2 mg/kg naloxone to precipitate withdrawal 1 hour after the last morphine injection. Rats in the control group were treated with an equal volume of saline. MAIN OUTCOME MEASURES： Following morphine dependence and withdrawal, brain levels of the neurosteroids pregnenolone, progesterone and allopregnanolone were analyzed using gas chromatography-mass spectrometry. The mRNA expression of two key steroidogenic enzymes, P450 side-chain cleavage enzyme （P450scc） and 3[B-hydroxysteroid dehydrogenase （313-HSD）, were determined in rat brain regions using reverse transcription-polymerase chain reaction. The distribution and expression of P450scc protein were visualized in brain regions associated with addiction by immunohistochemistry. RESULTS： In brain tissue from the morphine dependence group, the levels of pregnenolone and progesterone were decreased by 62% （P 〈 0.01） and 92% （P 〈 0.01 ） respectively, compared with the control group. In the morphine dependence group, the key steroidogenic enzyme P450scc mRNA was decreased in striatum （P 〈 0.05）, while 3-HSD mRNA was decreased in amygdala （P 〈 0.05）, striatum （P 〈 0.05） and frontal cortex （P 〈 0.05） compared with the control group. Morphine withdrawal induced a significant increase in the neurosteroid levels compared with the control group （P 〈 0.01）. However, there was no significant difference in the expressions of P450scc and 36-HSD mRNAs between the morphine withdrawal and control groups （P 〉 0.05）. CONCLUSION： The neurosteroid levels and expressions of steroidogenic enzymes changed similarly in morphine dependent rats, suggesting that the morphine dependence-induced decrease in neurosteroids might depend on local expression of steroidogenic enzymes in the central nervous system. However, the changes in neurosteroids in morphine withdrawal rats were not in accordance with the changes in the expression of steroidogenic enzymes, suggesting that the effects of morphine withdrawal on brain neurosteroid levels may not depend primarily on the local expression of steroidogenic enzymes in the central nervous system.

Sidiming attenuates morphine withdrawal syndrome and nitric oxide (synthase) levels in morphine-dependent rats and rhesus monkeys

The present study analyzed the effects of Sidiming, a Chinese herbal compound, on withdrawal syndrome, body weight loss, and serum levels of nitric oxide and its synthase in morphine- dependent rats and rhesus monkeys. These effects were compared with clonidine, an active control drug used for clinical treatment. Results showed that 4 and 8 g/kg Sidiming, respectively, significantly suppressed morphine withdrawal syndrome and reduced body mass loss in morphine-dependent rats. In addition, 2.4 and 4.8 g/kg Sidiming, respectively, significantly attenuated withdrawal syndrome in rhesus monkeys. High-dose Sidiming （8 g/kg in rats and 4.8 g/kg in rhesus monkeys） led to significantly inhibited serum levels of nitric oxide and its synthase in morphine-dependent rats and rhesus monkeys, which were greater than clonidine. These findings suggested that Sidiming treatment attenuated withdrawal syndrome in morphine-dependent rats and rhesus monkeys by inhibiting serum nitric oxide and its synthase.

Morphine pre-exposure facilitates reinstatement but attenuates retention of morphine-induced place preference

BACKGROUND： Drug-associated conditioned stimuli are a key factor to induce morphine relapse. To date, limited evidence is available regarding the impact of drug history on propensity or vulnerability to relapse after long-term abstinence. OBJECTIVE： To determine the effect of morphine pre-exposure on acquisition, maintenance and reinstatement of morphine-induced conditioned place preference （CPP） in rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Behavior Pharmacology, Institute of Psychology, the Chinese Academy of Sciences, from March to September, 2006. MATERIALS： Morphine hydrochloride was purchased from Qinghai Pharmaceutical, China; CPP software was designed and developed by Taiji Software Company, Beijing, China. METHODS： A total of 64 Sprague Dawley rats were randomly assigned to eight groups （n = 8）. Four morphine pretreatment regimens were used （subcutaneous injections, twice daily for 5 consecutive days and a total of 10 times）： （1） ＂intensive＂ （morphine injections with doses escalating from 10 to 60 mg/kg; （2） ＂moderate＂ （one morphine injection at 5 mg/kg dose and one saline injection at 1 mL/kg daily for 5 days）; and （3） ＂single＂ （nine saline injections at 1 mL/kg followed by one morphine injection at 5 mg/kg; （4） control （ten saline injections at 1 mL/kg）. At 5 days after morphine pretreatment, animals were divided into two subgroups that underwent morphine conditioned or saline conditioned training. The test for acquisition of CPP was performed 24 hours after CPP training. The retention of morphine CPP was measured by repeated tests performed weekly for 1 month after the initial test of place preference. After extinction by pairing each chamber with saline, the reinstatement of place preference by low doses of morphine （0.05, 0.15, 0.45 mg/kg） was tested. MAIN OUTCOME MEASURES： Acquisition, maintenance, and recovery response of CPP behavior. RESULTS： The acquisition magnitude of morphine-induced CPP was not affected by prior morphine exposure （F3, 56=0.17, P 〉 0.05）. However, rats treated with moderate or intensive morphine pretreatment showed a less persistent CPP （t = -1.36, P 〉 0.05; t = -1.18, P 〉 0.05）, but their place preference was reinstated by a low dose of morphine priming （t = -2.55, P 〈 0.05; t = -2.54, P 〈 0.05）. The retention and reinstatement of morphine-induced CPP did not differ between rats with single morphine pre-exposure and control rats. CONCLUSION： Morphine pretreatment enhanced reinstatement of morphine-induced CPP but with less persistence. Individuals with heavy drug exposure are more susceptible to drug relapse when re-exposed to addictive drugs.

Brain regional changes of guanine nucleotide binding protein-inhabitant 2 in acute and chronic morphine-tolerant and-dependent rats

BACKGROUND： Drug addiction involves two main central nervous systems, namely the dopamine and noradrenaline systems. These systems are primarily distributed in five brain regions： the ventral tegmental area, the nucleus accumbens, the prefrontal cortex, the hippocampus, and the locus coeruleus. OBJECTIVE： To investigate regional changes of guanine nucleotide binding protein-inhabitant 2 （Gi2） in dopaminergic and noradrenergic neurons in brains of morphine-tolerant and -dependent rats. DESIGN, TIME, AND SETTING： A randomized control study was performed at the Department of Neurobiology in the Second Military Medical University of Chinese PLA （Shanghai, China） between September 2002 and March 2004. MATERIALS： Thirty-six, healthy, male, Sprague-Dawley （SD） rats were used to establish morphine-dependent models. Morphine hydrochloride was a product of Shenyang First Pharmaceutical Factory （China）; naloxone hydrochloride was a product of Beijing Four-Ring Pharmaceutical Factory （China）; and α subunit of Gi2 antibody was offered by Santa Cruz Biotechnology, lnc （USA）. METHODS： Thirty-six SD rats were randomly divided into six groups （n = 6）： （1） acute morphine-dependent group, （2） acute abstinent group, （3） acute control group, （4） chronic morphine-dependent group, （5） chronic abstinent group, and （6） chronic control group. Rats in the acute morphine-dependent and the acute groups were injected with morphine （5 mg/kg）, one injection every two hours, for a total of eight injections. In the acute and chronic morphine-dependent rat models, morphine withdrawal syndrome was precipitated by an injection of naloxone （5 mg/kg）. Rats in the acute control group were given a peritoneal injection of physiological saline at the same administration time as the above two groups. Rats in the chronic morphine-dependent and chronic abstinent groups were injected with morphine three times per day. The administration dose on day 1 was initially 5 mg/kg at 20：00, which increased by 5 mg/kg at 8：00, 12：00, and 20：00 until day 7. On day 13, the dose continuously increased by 10 mg/kg until a chronic morphine-dependent rat model was successfully induced. Afterwards, the rats presented with withdrawal syndromes on naloxone （5 mg/kg） at 8：00 on the same day. Rats in the chronic control group were injected with physiological saline at the same time of the two chronic groups. MAIN OUTCOME MEASURES： The concentration of Gi2 protein in the five brain regions （ventral tegmental area, nucleus accumbens, prefrontal cortex, locus coeruleus, and hippocampus） was detected by immunohistochemistry. RESULTS： In the acute morphine-dependent and acute abstinent groups, Gi2 protein concentration was significantly decreased in the nucleus accumbens, compared to the acute control group （P 〈 0.01）, while no obvious changes were detected in other brain regions. In the chronic morphine-dependent and chronic abstinent groups, Gi2 protein concentration was significantly decreased in the nucleus accumbens, but significantly increased in the locus coeruleus （P 〈 0.01 ） compared to the chronic control group. CONCLUSION： Morphine dependence and tolerance may induce obvious reductions of Gi2 protein levels in the nucleus accumbens of rats. Chronic morphine dependence desensitizes the homologous neurons.

Expression changes of hippocampal energy metabolism enzymes contribute to behavioural abnormalities during chronic morphine treatment

学习和记忆的依赖和缺陷是象 opioids 那样的滥用的药引起的二 well-establishedfeatures。马头鱼尾的怪兽是与两药依赖联系的一个重要区域并且学习并且记忆。然而，在到象 opioids 那样的滥用的药的马头鱼尾的怪兽追随者暴露的分子的事件很好没被理解。这里，我们由 proteomic 分析在海马趾的蛋白质表示上检验了长期的吗啡处理的效果。 Wefound 到为 10 天的吗啡的老鼠的那长期的暴露生产了柔韧的吗啡退却跳和记忆缺陷，并且也导致了三新陈代谢的酶的海马趾的蛋白质层次的一条重要down 规定包括 Fe-S 蛋白质 1 NADH 脱氢酶， pyruvate 建筑群和乳酸脱氢酶的 dihydrolipoamide acetyltransferase 或 E2 部件 2 。进一步即时的量的 PCR 分析证实相应 mRNAs 的层次显著地也被减少。与这些调查结果，更低的 ATP 层次和把葡萄糖变换成 ATP 的一个损害能力一致也在长期地对待的老鼠的马头鱼尾的怪兽被观察。显著地与吗啡附随地管理的 Opioid 对手 naltrexone 压制了吗啡退却跳并且颠倒了这些蛋白质的 down 规定。到吗啡的尖锐暴露也生产了跳的柔韧的吗啡退却和重要存储器缺陷，但是在吗啡管理显著地提高了 ATPlevels 并且压制了吗啡退却不在长期的对待吗啡的鼠标在尖锐 morphine-treatedbut 跳和存储器缺陷以前，没有通过 D 葡萄糖的这三 proteins.Intrahippocampal 注射的表达式到减少。D 葡萄糖的高剂量的 Intraperitoneal 注射在作为中央处理跳的导致吗啡的退却上显示出类似的效果。总起来说，我们的结果建议在由于长期的吗啡处理的马头鱼尾的怪兽的三新陈代谢的酶的那减少的表情贡献象吗啡退却跳和记忆缺陷那样的导致药的症状的发展。

Postmortem regional distribution of morphine in dependent rats

Objective: Morphine concentration measured in postmortem tissues may or may not reflect antemortem concentration. We measured levels of morphine in autopsied tissues to determine whether morphine distribution in morphine-dependent rats is altered after death. Methods: Solid-phase extraction was used to extract morphine from the samples, and morphine levels were measured at 0-96 h postmortem using gas chromatography. Results: The study of the morphine dependent rats showed a significant (P<0.05) increase of morphine concentration in postmortem cardiac blood, liver tissues and kidneys tissues. A significant increase was also observed at 72 h and 96 h postmortem in the brain, while morphine levels in cardiac tissues only increased at 24 h and 96 h postmortem. These changes were associated with an observed pH rapid decrease: pH of cardiac blood dropped from 7.36±0.15 to 6.86±0.09 (P<0.01), pH of liver tissues from 6.98±0.04 to 6.34±0.03 (P<0.05). Conclusion: The postmortem regional distribution of morphine occurs in dependent rats, but different from the change that occurs in acute poisoning rats. The morphine concentration in cardiac blood and tissues tends to increase during the period of 0-96 h postmortem in dependent rats. Morphine concentration increases with pH rapid decrease. The antemortem internal amount of morphine affects its postmortem regional distribution. It appears that several mechanisms are accountable for postmortem morphine distribution. The understanding of the mechanisms and patterns may eventually lead to better choices of samples which may better represent antemortem drug levels.

EFFECTS OF LOW-FREQUENCY ELECTROACUPUNCTURE ON THE IMMUNOLOGIC FUNCTION IN MORPHINE DEPENDENCE RATS

Objective: To observe the effect of low-frequency electroacupuncture (EA) on the immunologic function in morphine dependence rats. Methods: Forty SD rats were used in this study. Morphine-dependence model was established by intraperitoneal injection of morphine hydrochloride continuously for 5 days and hastened by administration (i.p) of Naloxone. These rats were randomly divided into control, model, EA and auto-demorphinization groups with 10 cases being in each group. In EA group, "Guanyuan"(CV 4),"Mingmen"(GV 4), etc. were punctured and stimulated electrically. Positive T lymphocyte subgroups, CD + 4 and CD + 8 in the peripheral blood were detected with fluorescence immuno-assay. Results: In model group, serum percentage of CD + 4 and CD + 4/CD + 8 decreased considerably in comparison with those of control group (P<0.01); while in EA group, CD + 4 level and CD + 4/CD + 8 increased significantly compared with those of model group (P<0.01); and no significant differences were found between auto-demorphinization group and model group and between EA and control groups in these two indexes. Conclusion: Low-frequency EA can promote the restoration of the immune function of morphine dependence rats.

Inhibitory effect of berberine on morphine tolerance and hyperalgesia in mice

OBJECTIVE: To evaluate the effect of berberine on morphine analgesia, tolerance, and hyperalgesia. METHODS: Morphine-induced acute tolerance model: mice received intraperitoneal berberine at doses of 2.5, 5.0, and 10 mg/kg;30 min later, subcutaneous morphine 10 mg/kg was injected every hour for nine continuous h. Morphine 10 mg/kg alone was administered at 24 and 48 h. Morphine-induced chronic tolerance model: mice received intraperitoneal berberine 2.5, 5.0, and 10 mg/kg;30 min later, 10 mg/kg morphine was injected subcutaneously for eight consecutive days. On the ninth day, morphine 10 mg/kg was given alone. Morphineinduced established tolerance model: mice were injected subcutaneously with morphine 10 mg/kg once a day for eight consecutive days. Berberine 2.5 mg/kg was administered on day one, four, and seven and morphine 10 mg/kg alone on day nine. The baseline latency(T0) and post-treatment latency(T1) were determined by the hot plate test, and the maximum possible analgesic effect (MPAE) was calculated. Nitric oxide synthase(NOS) activity and nitric oxide(NO) content in the spinal cord were measured by spectrophotometer. Verification of berberine analgesic effect by blocking N-methyl-Daspartate(NMDA) receptor: HT-22 and HEK-293 cells transfected with NMDA plasmid were randomly divided into five groups: control group, NMDA group, berberine low-dose, medium-dose, and high-dose groups(5, 10, 20 μmol/L, respectively). Except for the control group, cells were treated with NMDA(HT-22 cells: 20 mmol/L;HEK-293 cells: 50 μmol/L). After 24 h, cell viability was detected by cell counting kit-8. The molecular mechanism between berberine and the NMDA receptor was studied by molecular docking. RESULTS: Berberine 2.5 and 5.0 mg/kg could prolong the analgesic time of morphine. In acute and chronic morphine tolerance models, berberine could inhibit the decrease of MPAE and baseline latency(P < 0.05). In the established tolerance model, berberine could rapidly reverse the decreased MPAE(P < 0.05). The combination of berberine and morphine on day one could effectively inhibit the morphine-induced increase of NOS activity and NO content in the spinal cord(P < 0.05). Berberine significantly increased the cell viability of NMDA-induced nerve injury in HT-22 and HEK-293 cells(P < 0.05). Molecular docking showed that berberine binds to the receptor pocket of NMDA. CONCLUSIONS: Berberine could effectively enhance and prolong the duration of morphine analgesia and inhibit the development of morphine-induced tolerance and hyperalgesia. Furthermore, berberine has a certain neuroprotective effect, which may be related to the inhibition of NMDA activity.

Expression dynamics of periodic transcripts during cancer cell cycle progression and their correlation with anticancer drug sensitivity

Background:The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms,among which transcriptional regulation is one of the most important components.Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle.However,the patterns of transcript isoform expression in the cell cycle are unclear.Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies,but none of them have been designed or evaluated at the alternative splicing transcript level.The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown,and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare.Methods:To explore alternative splicing patterns during cell cycle progression,we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines,using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples,and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle.Genomics of Drug Sensitivity in Cancer(GDSC)drug sensitivity datasets and Cancer Cell Line Encyclopedia(CCLE)transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity.We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients.Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6(CDK4/6)inhibitors.Finally,alternative splicing transcripts associated with mitotic(M)phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis.Results:We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells.The results of the cell cycle assessment showed that 43,326,41,578 and 29,244 transcripts were found to be periodically expressed in HeLa,HCT116 and MDA-MB-231 cells,respectively,among which 1280 transcripts showed this expression pattern in all three cancer cell lines.Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes.Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904.The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts.Combined with the cell cycle-related drug screening,the results also showed that a set of periodic transcripts,for example,ENST00000314392(a dolichylphosphate mannosyltransferase polypeptide 2 isoform transcript),was more associated with drug sensitivity than the levels of their corresponding gene transcripts.Conclusions:In summary,we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity,providing novel insights into alternative splicing-related drug development and evaluation.

基于FAERS数据库的周期蛋白依赖性激酶4/6抑制剂血液毒性真实世界研究

目的 基于美国美国食品药品管理局(FDA)的不良事件报告系统(FAERS)分析3种周期蛋白依赖性激酶4/6(CDK4/6)抑制剂上市后的不良事件(AEs)信号,为临床用药安全提供参考。方法 提取FAERS数据库2015年第一季度至2022年第一季度共29个季度AEs,利用报告比值比法(ROR)和比例报告比值法(PRR)对CDK4/6抑制剂AEs进行数据挖掘。结果 CDK4/6抑制剂相关性血液毒性报告共有7 872份,各抑制剂血液毒性AEs占总AEs比例依次为哌柏西利(80.31%)>瑞博西利(15.36%)>阿贝西利(4.33%)。血液毒性常见中性粒细胞减少和贫血。哌柏西利(2 982/6 322,47.17%)和瑞博西利(613/1 209,50.70%)致中性粒细胞减少的报告占比较阿贝西利(117/341,34.31%)更高,血液毒性主要发生在药物开始使用后60 d内(1 630,61.86%),哌柏西利中位时间最长,且用药90 d后仍有32.9%的患者存在血液毒性,不同CDK4/6抑制剂血液毒性临床表现及发生强度存在差异。结论 哌柏西利、阿贝西利、瑞博西利均会导致明显的血液毒性,其中阿贝西利致血液毒性报告最少,但要警惕阿贝西利致贫血后导致死亡的风险。用药后的2个月内密切监测全血细胞计数,关注中性粒细胞、血红蛋白等水平,警惕CDK4/6抑制剂相关血液AEs的发生。

Inhibition of the reinstatement of morphine-induced place preference in rats by high-frequency stimulation of the bilateral nucleus accumbens

Background Opiate addiction remains intractable in a large percentage of patients, and relapse is the biggest hurdle to recovery. Many studies have identified a central role of the nucleus accumbens （NAc） in addiction. Deep brain stimulation （DBS） has the advantages of being reversible, adjustable, and minimally invasive, and it has become a potential neurobiological intervention for addiction. The purpose of our study was to investigate whether high-frequency DBS in the NAc effectively attenuates the reinstatement of morphine seeking in morphine-primed rats. Methods A morphine-dependent group of rats was given increasing doses of morphine during conditioned place preference training. A control group of rats was given equal volumes of saline. After the establishment of this model, withdrawal syndromes were precipitated in these two groups by administering naloxone, and the differences in withdrawal symptoms between the groups were analyzed. Electrodes for DBS were implanted in the bilateral shell of the NAc in the experimental group. The rats were stimulated daily in the NAc for 5 hours per day over 30 days. Changes in the conditioned place preference test and withdrawal symptoms in the rats were investigated and place navigation studies were performed using the Morris water maze. The data were assessed statistically with one-way analysis of variance （ANOVA） followed by Tukey＇s tests for multiple post hoc comparisons. Results High-frequency stimulation of the bilateral NAc prevented the morphine-induced reinstatement of morphine seeking in the conditioned place preference test. The time spent in the white compartment by rats following 30 days of DBS （（268.25±25.07） seconds） was not significantly different compared with the time spent in the white compartment after relapse was induced by morphine administration （（303.29±34.22） seconds）. High-frequency stimulation of the bilateral NAc accelerated the innate decay of drug craving in morphine-dependent rats without significantly influencing learning and memory. Conclusion Bilateral high-frequency stimulation of the shell of the NAc may be useful as a novel therapeutic modality for the treatment of severe morphine addiction.

孕妇药物依赖的胎儿权益与母体自主冲突之思考

聚焦医学伦理学视角下孕妇药物依赖及其对胎儿健康的潜在影响,探索胎儿权利与母体自主权之间的伦理平衡及在医疗与社会法律层面的复杂挑战。探讨了胎儿权益与母体自主间的伦理张力,分析了药物依赖的成因,包括治疗性药物使用和药物滥用,进而审视全球孕妇药物依赖现状及其影响。同时,评估了医学伦理四大原则在两种情境中的应用挑战,以及法律在定义和处理该伦理问题时的作用与临床实践中的差异。强调了公共卫生策略在解决孕妇药物依赖问题中的重要性,并提出了具体实施策略,以期为医疗从业者和政策制定者提供理论与实践指导。

Involvement of dynorphin A in the inhibition of morphine physical dependence by N-nitro-L-arginine in rats

Objective To investigate the involvement of immunoreactive dynorphin A in the inhibitory effect of N nitro L arginine on the morphine physical dependence in rats Methods The rats were rendered dependent on morphine by subcutaneous administration of morphine solution three times daily in a manner of dose increment of 5 mg·kg 1 for 6 days The degree of morphine physical dependence was monitored by scoring the abstinence syndromes precipitated by 5 mg·kg 1 naloxone of the rats The expression levels of immunoreactive dynorphin A in tissues were determined using a radioimmunoassay Results Intraperitoneal injection of 5 mg·kg 1 N nitro L arginine suppresses most of the withdrawal symptoms of morphine dependent rats N nitro L arginine can elevate the expression of immunoreactive dynorphin Conclusions Chronic N nitro L arginine administration can inhibit the development of morphine physical dependence in a manner of dose dependence, which is significantly related to its role of regulating the endogeneous dynorphin system

Agmatine inhibited tolerance to and dependence on morphine in guinea pig ileum in vitro

目的：观察胍丁胺对吗啡耐受和物质依赖豚鼠回肠纵肌（ＧＰＩＬＭ）的作用．方法：本实验在离体电场刺激实验中进行．结果：吗啡抑制ＥＦＳ引起的ＧＰＩＬＭ收缩［ＩＣ５０＝１４０（１０７－１８２）ｎｍｏｌ·Ｌ－１］．用吗啡２７０ｎｍｏｌ·Ｌ－１与ＧＰＩＬＭ温浴使吗啡ＩＣ５０增大３７倍（耐受），对纳络酮发生收缩反应（物质依赖）．分别用吗啡加纳络酮和吗啡加胍丁胺与ＧＰＩＬＭ温浴使吗啡失去此致耐受作用，使标本对纳络酮收缩反应幅度分别减少了９０％和７５％．胍丁胺的这些作用几乎可被咪唑克生完全阻断．