Low Concentrations Of Morphine Research Articles

Electrochemical measurement of morphine using a sensor fabricated from the CuS/g-C3N5/Ag nanocomposite

Morphine, as one of the most important narcotic drugs, significantly affects the nervous system and increases euphoria, which raises the likelihood of its misuse. Therefore, its measurement is of great importance. In this work, a new electrochemical sensor based on a nanocomposite of CuS/g-C3N5/AgNPs was developed for modifying Screen printed carbon electrodes (SPCEs) and used for the measurement of morphine through cyclic voltammetry and differential pulse voltammetry. Various analytical methods initially characterized the nanocomposite. The prepared sensor, which also has an extensive surface area, achieved a detection limit of 0.01 µM for morphine in a concentration range of 0.05–100 µM at pH 7. Besides its excellent capability in measuring morphine in real samples, the sensor exhibits good stability, reproducibility, and repeatability. The presence of CuS, due to its excellent high surface area alongside silver nanoparticles, leads to an increase in the conductivity of the g-C3N5 modified electrode, resulting in an increased oxidative current of morphine at the surface of the prepared sensor. Therefore, measuring low concentrations of morphine with this sensor was made possible. Additionally, measuring morphine without interference from various species is a strong point of the electrochemical sensor for morphine detection, and combined with the simplicity and ease of the method, it allows for morphine measurements to be conducted in the shortest possible time.

Bidirectional effects of morphine on pancreatic cancer progression via the p38/JNK pathway

Cancer patients commonly use morphine to alleviate advanced pain. Studies have shown that morphine may influence and intervene in the malignancy of various cancers, but its role and effects on pancreatic cancer are less studied. This study aims to examine how morphine affects pancreatic cancer and its possible mechanisms. In vitro experiments were conducted using the CCK-8 experiment, colony formation experiment, EdU test, wound healing experiment, and transwell migration and invasion experiment. Tumor xenograft tests were employed to investigate the in vivo impact of morphine on pancreatic cancer. The Western blot (WB) assay was used to detect possible changes in key proteins of the related signaling pathway. Our experimental results showed that low concentrations of morphine (25 µM) promoted the progression of pancreatic cancer, while high concentrations of morphine (100 µM) inhibited its progression. Further, we demonstrated that morphine may interfere with the progression of pancreatic cancer by acting on the p38/JNK signaling pathway. Morphine may affect pancreatic cancer progression through the p38/JNK pathway in a bidirectional manner at different concentrations.

An Unusual Case of High 6-Monoacetylmorphine and Low Morphine in Urine: Heroin Abuse or Analytical Error?

A 59-year-old male with a past medical history of chronic low back pain, opioid use disorder, and type 2 diabetes mellitus presented to an outpatient clinic for pain contract–related urine drug screen testing. Current medications included metformin, oxycodone, and Suboxone® (buprenorphine and naloxone combination). The patient stated that 5 days prior to the visit, he stopped taking Suboxone due to complaints of nausea and vomiting. Urine toxicology test results are summarized in Table 1. ... ... Suboxone is an opioid abuse management medication that is formulated with buprenorphine and naloxone. Naloxone has limited bioavailability when administered sublingually and should be barely detectable in urine. However, when Suboxone is taken parenterally, naloxone enters the blood stream and is largely excreted in urine. In this case, the presence of a high concentration of naloxone in urine with a high ratio to buprenorphine suggested parenteral administration (1). Heroin is readily metabolized into 6-MAM and then to morphine. Typically, the 6-MAM-to-morphine ratio is <0.26, so it is uncommon to see a high positive 6-MAM with very low morphine concentrations (2). The calculated 6-MAM-to-morphine ratio in this sample was 7.27. Conversion from morphine to 6-MAM due to contaminants in enzyme hydrolysis or acid hydrolysis used during sample preparation in urine samples with extremely high morphine (>100 000 μg/L) has been reported (3). In our case, morphine was very low, so this was unlikely, but to rule out any analytical cause, the positive urine sample was sent to a reference laboratory, which confirmed our findings. The fact that 2 laboratories using different mass spectrometry–based methods showed detectable 6-MAM supported heroin use, instead of a false positive due to an interference. The unusually low morphine result in some heroin users has been reported elsewhere and may be mostly attributed to inhibitors of carboxylesterases from the heroin synthesis process (2) or explained by polymorphism in the esterase enzymes metabolizing 6-MAM to morphine (4). The physician also requested serum fentanyl testing by mass spectrometry 5 days after the original urine sample collection (fentanyl was not part of our general urine drug screen), which came back positive for fentanyl and norfentanyl. In addition to the unexpected positive amphetamine result, all of this confirmed that this patient suffered from polysubstance abuse.

Low concentrations of morphine enhanced the neuroglia-like differentiation

The present study was undertaken to evaluate the effects of different concentrations of morphine in chronic manner on neuroglial differentiation in PC12 cells. PC12 cells were cultured in RPMI 1640 culture medium including 0.02 % bovine serum albumin together with different concentrations of morphine for 12 days. Cytotoxicity was performed by lactate dehydrogenase assay. Cell death was performed by PI/Hoechst staining assay. Neuroglial differentiation was performed by Nestin, Tuj-1, MAP-2, S-100 and GFAP Immunocytochemistry assay. Data showed that morphine either at low or high concentration activated opioid receptors, which resulted in a decrease of cytotoxicity and cell death and induction of Nestin, Tuj-1, MAP-2, Neurofilament-M (NF-M), GFAP and S-100 protein expression as compared in treated cells with the control (untreated cells) (p<005). It can be concluded that low concentrations of morphine in chronic manner stimulate the neuroglial-like differentiation by activating protein expression and survival-promoting signaling in PC12 cells with opioid receptor-dependent mechanism (Fig. 8, Ref. 36). Text in PDF www.elis.sk.

Preconcentration of morphine in urine sample using a green and solvent-free microextraction method

Abstract The ability of extraction and preconcentration of small amounts of substances from biological samples is very important in medical toxicology. On the other hand, minimal use of organic solvents is an important issue to prevent environmental damage. In the present study, we developed a new solid phase microextraction fiber using plant extracts as sorbent for extraction and preconcentration of morphine in urine sample. For this purpose, raw carbon nanotubes (CNTs) were functionalized with tobacco extracts. Functionalization was confirmed by Fourier transform infrared (FTIR) and Raman spectroscopy in addition to scanning electron microscope (SEM) images. The functionalized CNTs were coated on polypropylene hollow fiber. The results of HPLC analysis showed that the produced fiber could preconcentrate a very low concentration of morphine (0.25 ng/ml) in small volume of urine samples. Limit of detection (LOD) and limit of quantification (LOQ) for the produced fiber were determined 0.25 ng/ml and 0.825 ng/ml, respectively, and recovery of the fiber was determined 89% at LOQ. The produced fiber provided a recyclable and solvent free method for extraction of a trace amount of morphine, which can be successfully used for up to 30 times with no significant loss in the extraction efficiency.

Functionalization of graphene quantum dots with antimorphine: Design of selective nanosensor for detection of morphine

Surface functionalization of graphene quantum dots (GQDs) with antimorphine produced a new turn-on fluorescent nanosensor for morphine detection. The antimorphine-GQDs were prepared through the covalent conjugation of GQDs with antimorphine. FT-IR and X-ray photoelectron spectroscopies (XPS) confirmed the conjugation of antimorphine to GQDs. Fluorescence intensity of the antimorphine-GQDs enhanced after addition of morphine allowing its sensitive determination with detection limit of 0.06 μM. Further experiments revealed that this nanosensor has no interaction with other narcotics such as methamphetamine and codeine. Thus, it can act as inexpensive and selective nanosensor for specification of low concentrations of morphine.

Potential application of amino acids in analytical toxicology

The ability of extraction and preconcentration of small quantities of substances from biological samples is important in analytical sciences, particularly forensic medicine. In the present study, we evaluated the binding potential of amino acids to produce a new solid phase microextraction fiber based on carbon nanotube (CNTs) for extraction and preconcentration of small amount of morphine in urine sample. Raw CNTs were first carboxylated and then functionalized with 3 amino acids including glutamate, arginine, and cysteine. Functionalization was confirmed by FTIR analysis, Raman spectroscopy and SEM imaging. The functionalized CNTs were coated on polypropylene hollow fiber and used for preconcentration. The results of HPLC analysis in isocratic elution mode using acetonitrile-sodium acetate (10:90, v/v; pH 4; 0.01 M) as the mobile phase showed that amino acids are able to adsorb morphine and the prepared fiber could preconcentrate a very low concentration of morphine (0.25 ppb) in urine matrix. In addition, the fiber was successfully used for up to 30 times with no significant loss in the extraction efficiency. Lowest limit of detection (LOD) and limit of quantitation (LOQ) was 0.07 and 0.25, respectively. Also, the lowest and best recovery of the fiber was 87.8% and 139% at LOQ, which belonged to glutamate and arginine, respectively. The fibers based on amino acids can be used for the detection of a small amount of morphine in biological samples, which are not detectable by conventional methods. Simple mechanism of these fibers in preconcentrating morphine makes them a novel candidate for detection of other opiates and drugs of abuses in crime scene investigations and postmortem examinations several days after exposure.

Low concentration of morphine protects against cell death, oxidative stress and calcium accumulation by nicotine in PC12 cells.

Nicotine causes cell death in many cell lines. Morphine at low concentrations has protective effects against cell death. We investigated the effects of low concentration of morphine on nicotine-induced cell death in PC12 cells. PC12 are cells that grow in DMEM culture medium. Cell viability was detected by MTT test and cells cytotoxicity was measured by LDH test. The activity of caspase-3 was diagnosed by the caspase activity colorimetric assay kit, and detection of mitochondrial membrane potential was confirmed by rhodamine 123 and TUNEL test was performed for DNA fragmentation detection. The fura-2 AM and also rhod 2-AM was used for measurement of intracellular calcium (Ca2+) ic and mitochondrial calcium (Ca2+) m and finally, measurement of antioxidant enzyme activities was assessed. The low concentration of morphine increased cell viability and suppressed cell cytotoxicity, cell death and the formation of mitochondrial membrane potential compared to nicotine treated cells. It also reduced the intracellular calcium (Ca2+) ic and mitochondrial calcium (Ca2+)m concentration, respectively. Morphine as a pain reducer drug, in low concentrations, can protect PC12 cells from nicotine-induced cell death (Fig. 7, Ref. 59).

Developing a new sensitive solid-phase microextraction fiber based on carbon nanotubes for preconcentration of morphine

The ability of extraction and preconcentration of small amounts of substances from biological samples is important in forensic medicine. In the present study, we produced a new solid-phase microextraction fiber based on carbon nanotube (CNTs) for extraction and preconcentration of small amount of morphine in urine sample. Raw nanofibers were first carboxylated with H2SO4/HNO3 (3:1) and then functionalized with ethylenediamine. Functionalization was confirmed by FTIR and Raman spectroscopy as well as SEM analysis. The functionalized CNTs were coated on a porous polypropylene hollow fiber. A new electrical device was designed and manufactured for adsorption–desorption of the analyte, in which the voltage could be reversed and the analytes could desorb into the washing solution for HPLC analysis. The results showed that the prepared fiber could adsorb a very low concentration of morphine (0.5 ppb) in urine matrix, and was successfully used for up to 50 times with no significant loss in the extraction efficiency. Recovery of the fiber was 77% at 0.5 ppb. The optimum condition for the fiber was 2 min at 1 V of the manufactured electrical catalyst controller. This fiber can be used for the detection of a small amount of morphine in biological samples, which are not detectable by conventional methods. Simple mechanism of this fiber in preconcentrating morphine makes it a novel candidate for detection of other opiates and drugs of abuses in crime scene investigations and postmortem examinations several days after exposure. The prepared electric microextraction device could also efficiently concentrate the morphine in the urine matrix.

'Opioidergic postconditioning' of heart muscle during ischemia/reperfusion injury.

Ischemic preconditioning and postconditioning are the novel strategies of attaining cardioprotection against ischemia/reperfusion (I/R) injury. Previous studies suggested the role of opioid pathway, however the class of opioid receptors responsible for this effect in humans remains unknown. The aim of the study was to assess the influence of opioids on simulated I/R injury outcomes in the hu-man myocardium. Trabeculae of the human right atrium were electrically driven in organ bath and subjected to simulated I/R injury. Morphine (10-4M, 10-5M, 10-6M) or d-opioid receptor agonist DADLE (10-8M, 10-7M, 10-6M) was used at the time of re-oxygenation. Additional trabecula was subjected to hypoxia protocol only (Control). Contractive force of the myocardium was assessed as the maximal force of a contraction (Amax), the rate of rise of the force of a contraction (Slope L) and relaxation as the rate of decay of the force of a contraction (Slope T). Application of morphine 10-4M resulted in increase of Amax, Slope L and Slope T during re-oxygenation period as compared to Control (77.99 ± 1.5% vs. 68.8 ± 2.2%, p < 0.05; 45.72 ± 2.9% vs. 34.12 ± 5.1%, p < 0.05; 40.95 ± 2.5% vs. 32.37 ± 4.3%, p < 0.05). Parameters were not significantly different in the lower morphine concentrations. Application of DADLE 10-6M resulted in decrease of Amax and Slope L as compared to Control (68.13 ± 5.5% vs. 76.62 ± 6.6%, p < 0.05; 28.29 ± 2.2 vs. 34.80 ± 3.9%, p < 0.05). At re-oxygenation, morphine improves systolic and diastolic function of the human myo-cardium in the dose-dependent manner. Delta-opioid receptor stimulation attenuates systolic function of human heart muscle which remains in contrast to previous reports with animal models of I/R injury. (Cardiol J 2017; 24, 4: 419-425).

Dose-dependent effects of morphine on lipopolysaccharide (LPS)-induced inflammation, and involvement of multixenobiotic resistance (MXR) transporters in LPS efflux in teleost fish

Opioid drugs, such as morphine (MO), detected in aquatic environments worldwide, may harm fish due to their semi-persistence and ability to potently interact with molecular targets conserved across vertebrates. Here, we established a waterborne bacterial lipopolysaccharide (LPS) challenge assay with zebrafish embryos as a model to investigate chemically-induced disruption of the innate immune system, and used it to study the effects of MO exposure. Exposure to 1 mg/L MO resulted in pronounced immunosuppression, reflected in downregulation of several inflammation-related genes, including myd88, trif, traf6, p38, nfκb2, il-1β, il-8 and ccl34a. Fish exposed to 1 mg/L MO accumulated 11.7 ng/g (wet weight) of MO, a concentration comparable to that reported in blood of chronic drug abusers subject to higher infection rates. Surprisingly, exposure to lower MO concentrations (100 ng/L–100 μg/L) led to exacerbation of LPS-induced inflammation. Two ATP-binding cassette (ABC) transporters known to be involved in the xenobiotic efflux - abcb4 and abcc2, also known as multixenobiotic resistance (MXR) transporters - were downregulated at 100 ng/L MO. We hypothesized that ABC/MXR transporters could modulate the severity of inflammation by being involved in efflux of LPS, thus regulating its accumulation in the organism. Indeed, we could demonstrate that blocking of ABC/MXR transporters by an inhibitor, cyclosporine A, results in stronger inflammation, coinciding with higher LPS accumulation, as visualized with fluorescently labeled LPS. Our work demonstrates that MO can disrupt fish innate immune responses at environmentally relevant concentrations. We also provide evidence for a role of ABC/MXR transporters in LPS efflux in fish. These finding may be applicable across other taxa, as ABC transporters are evolutionary conserved. Since diverse environmentally present chemicals are known to interfere with ABC/MXR transporters' expression or activity, our discovery raises concerns about potential adverse effects of such compounds on the immune system responses in aquatic organisms.

Heroin overdose.

This narrative review aims to provide a brief history of the development of the heroin overdose field by discussing a selection of major 'classics' from the latter part of the 20th century. Papers considered landmarks were selected from 1972, 1977, 1983, 1984 and 1999. Findings of earlier works suggest much of what later research was to demonstrate. These include arguing that overdoses occurred primarily among tolerant older users, that most 'overdose' deaths involved low morphine concentrations, that most overdoses involve polypharmacy, that drug purity has only a moderate influence on overdose rates and that instant death following heroin administration is rare. Landmark studies of heroin overdose from the 1970s, 1980s and 1990s laid the foundations for subsequent overdose research, mainly by identifying the major demographic characteristics of overdose cases, risk factors, survival times and behaviours at overdose events.

Evaluation of Common Adulterants in Morphine Urine Drug Screening

Background: Manipulating drug screens, changing sample quality, and confounding test results are common practices seen among opium users. These practices are intended to deceive drug screening systems using a wide variety of commonly available chemical compounds such as lemon juice and fertilizer. These actions create a challenge for addiction screening reference labora- tories. Objectives: Therefore, we studied the eects of lemon juice, nitrogen-based chemical fertilizers, carbon copy paper, and urine sam- ple dilution on morphine urine screening test results. PatientsandMethods: We studied the urine samples of all individuals who were referred to the drug laboratory at Sabzevar public health center from August 2014 to August 2015. Out of 8012 urine samples tested in one year, morphine metabolites were identified in 493 (6%) of the urine samples using a rapid morphine slide test and thin-layer chromatography. Next, 180 confirmed positive samples were randomly assigned to three groups of 60 samples each, to which were added either carbon paper, lemon juice, or nitrogen-based fertilizer. Results: The test results showed that in the carbon paper and lemon juice groups, 59 samples tested positive for morphine, and one sample was distorted. In the fertilizer group, 57 samples were positive and 3 were distorted. None of the groups showed negative test results. Moreover, negative results were not seen when testing standard samples that had been adulterated in the test kit's sensitivity range and higher. However, fertilizer and lemon juice adulteration, but not carbon paper, can lead to false negative results with lower morphine concentrations (150 ng/mL). Conclusions: We found that adding nitrogen-based fertilizer, lemon juice, or carbon copy paper to urine samples does not facilitate false negative results when using a rapid slide morphine urine test. However, testing samples of various standard concentrations of morphine showed that at lower morphine concentrations, adding lemon juice or fertilizer can aect the test results.

First demonstration that brain CYP2D-mediated opiate metabolic activation alters analgesia in vivo

The response to centrally acting drugs is highly variable between individuals and does not always correlate with plasma drug levels. Drug-metabolizing CYP enzymes in the brain may contribute to this variability by affecting local drug and metabolite concentrations. CYP2D metabolizes codeine to the active morphine metabolite. We investigated the effect of inhibiting brain, and not liver, CYP2D activity on codeine-induced analgesia. Rats received intracerebroventricular injections of CYP2D inhibitors (20μg propranolol or 40μg propafenone) or vehicle controls. Compared to vehicle-pretreated rats, inhibitor-pretreated rats had: (a) lower analgesia in the tail-flick test (p<0.05) and lower areas under the analgesia-time curve (p<0.02) within the first hour after 30mg/kg subcutaneous codeine, (b) lower morphine concentrations and morphine to codeine ratios in the brain (p<0.02 and p<0.05, respectively), but not in plasma (p>0.6 and p>0.7, respectively), tested at 30min after 30mg/kg subcutaneous codeine, and (c) lower morphine formation from codeine ex vivo by brain membranes (p<0.04), but not by liver microsomes (p>0.9). Analgesia trended toward a correlation with brain morphine concentrations (p=0.07) and correlated with brain morphine to codeine ratios (p<0.005), but not with plasma morphine concentrations (p>0.8) or plasma morphine to codeine ratios (p>0.8). Our findings suggest that brain CYP2D affects brain morphine levels after peripheral codeine administration, and may thereby alter codeine's therapeutic efficacy, side-effect profile and abuse liability. Brain CYPs are highly variable due to genetics, environmental factors and age, and may therefore contribute to interindividual variation in the response to centrally acting drugs.

Effects of μ‐opioid receptor modulation on the hippocampal network activity of sharp wave and ripples

Hippocampus-dependent memory involves the activity of sharp wave ripples (SWRs), which are thought to participate in the process of memory consolidation. The hippocampus contains high levels of endogenous opioids and of μ-opioid receptors (MORs). Here, we have assessed the role of MOR agonists in the modulation of SWRs. Using recordings of extracellular potentials from the CA1 field of rat hippocampal slices, we examined the pharmacological actions of morphine, DAMGO and fentanyl on SWRs and on network excitability and paired-pulse inhibition. All three MOR agonists (1 nM-10 μM) significantly increased the amplitude of sharp waves and the occurrence of SWR sequences, but reduced the initiation of episodes of SWRs. Fentanyl was most potent in producing these effects and morphine the least. Interestingly, although SWRs were reduced by relatively high concentrations (≥100 nM) of all agonists, they were significantly enhanced by very low concentrations of morphine (5-10 nM). Morphine and DAMGO at moderate-to-high concentrations increased network excitability and reduced inhibition. Furthermore, DAMGO suppressed inhibition more readily than it increased excitation, whereas morphine suppressed inhibition only at high concentrations. These drug effects were reversed by the MOR antagonists naloxone and CTOP. We found that the SWRs were significantly modulated by three MOR agonists and that the SWRs were very sensitive to subtle changes in the excitation/inhibition balance induced by MOR agonists. Such modulation might underlie the effects of these agonists on hippocampus-dependent memory.

Physical dependence and tolerance development to sustained low concentrations of morphine in mice.

Physical dependence and tolerance development to sustained low concentrations of morphine in mice.

Morphine Brain Pharmacokinetics at Very Low Concentrations Studied with Accelerator Mass Spectrometry and Liquid Chromatography-Tandem Mass Spectrometry

Morphine has been predicted to show nonlinear blood-brain barrier transport at lower concentrations. In this study, we investigated the possibility of separating active influx of morphine from its efflux by using very low morphine concentrations and compared accelerator mass spectrometry (AMS) with liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a method for analyzing microdialysis samples. A 10-min bolus infusion of morphine, followed by a constant-rate infusion, was given to male rats (n = 6) to achieve high (250 ng/ml), medium (50 ng/ml), and low (10 ng/ml) steady-state plasma concentrations. An additional rat received infusions to achieve low (10 ng/ml), very low (2 ng/ml), and ultralow (0.4 ng/ml) concentrations. Unbound morphine concentrations from brain extracellular fluid and blood were sampled by microdialysis and analyzed by LC-MS/MS and AMS. The average partition coefficient for unbound drug (K(p,uu)) values for the low and medium steady-state levels were 0.22 ± 0.08 and 0.21 ± 0.05, respectively, when measured by AMS [not significant (NS); p = 0.5]. For the medium and high steady-state levels, K(p,uu) values were 0.24 ± 0.05 and 0.26 ± 0.05, respectively, when measured by LC-MS/MS (NS; p = 0.2). For the low, very low, and ultralow steady-state levels, K(p,uu) values were 0.16 ± 0.01, 0.16 ± 0.02, and 0.18 ± 0.03, respectively, when measured by AMS. The medium-concentration K(p,uu) values were, on average, 16% lower when measured by AMS than by LC-MS/MS. There were no significant changes in K(p,uu) over a 625-fold concentration range (0.4-250 ng/ml). It was not possible to separate active uptake transport from active efflux using these low concentrations. The two analytical methods provided indistinguishable results for plasma concentrations but differed by up to 38% for microdialysis samples; however, this difference did not affect our conclusions.

Endogenous Morphine Levels Are Increased in Sepsis: A Partial Implication of Neutrophils

BackgroundMammalian cells synthesize morphine and the respective biosynthetic pathway has been elucidated. Human neutrophils release this alkaloid into the media after exposure to morphine precursors. However, the exact role of endogenous morphine in inflammatory processes remains unclear. We postulate that morphine is released during infection and can be determined in the serum of patients with severe infection such as sepsis.MethodologyThe presence and subcellular immunolocalization of endogenous morphine was investigated by ELISA, mass spectrometry analysis and laser confocal microscopy. Neutrophils were activated with Interleukin-8 (IL-8) or lipopolysaccharide (LPS). Morphine secretion was determined by a morphine-specific ELISA. μ opioid receptor expression was assessed with flow cytometry. Serum morphine concentrations of septic patients were determined with a morphine-specific ELISA and morphine identity was confirmed in human neutrophils and serum of septic patients by mass spectrometry analysis. The effects of the concentration of morphine found in serum of septic patients on LPS-induced release of IL-8 by human neutrophils were tested.Principal FindingsWe confirmed the presence of morphine in human neutrophil extracts and showed its colocalisation with lactoferrin within the secondary granules of neutrophils. Morphine secretion was quantified in the supernatant of activated human polymorphonuclear neutrophils in the presence and absence of Ca2+. LPS and IL-8 were able to induce a significant release of morphine only in presence of Ca2+. LPS treatment increased μ opioid receptor expression on neutrophils. Low concentration of morphine (8 nM) significantly inhibited the release of IL-8 from neutrophils when coincubated with LPS. This effect was reversed by naloxone. Patients with sepsis, severe sepsis and septic shock had significant higher circulating morphine levels compared to patients with systemic inflammatory response syndrome and healthy controls. Mass spectrometry analysis showed that endogenous morphine from serum of patient with sepsis was identical to poppy-derived morphine.ConclusionsOur results indicate that morphine concentrations are increased significantly in the serum of patients with systemic infection and that morphine is, at least in part, secreted from neutrophils during sepsis. Morphine concentrations equivalent to those found in the serum of septic patients significantly inhibited LPS-induced IL-8 secretion in neutrophils.

Is withdrawal hyperalgesia in morphine-dependent mice a direct effect of a low concentration of the residual drug?

Withdrawal of opioid drugs leads to a cluster of unpleasant symptoms in dependent subjects. These symptoms are stimulatory in nature and oppose the acute, inhibitory effects of opiates. The conventional theory that explains the opioid withdrawal syndrome assumes that chronic usage of opioid drugs activates compensatory mechanisms whose stimulatory effects are revealed upon elimination of the inhibitory opioid drug from the body. Based on previous studies that show a dose-dependent dual activity of opiates, including pain perception, we present here an alternative explanation to the phenomenon of withdrawal-induced hyperalgesia. According to this explanation, the residual low concentration of the drug that remains after cessation of its administration elicits the stimulatory withdrawal hyperalgesia. The goal of the present study was to test this hypothesis. In the present study we rendered mice dependent on morphine by a daily administration of the drug. Cessation of morphine application elicited withdrawal hyperalgesia that was completely blocked by a high dose of the opiate antagonist naloxone (100 mg/kg). Similarly, naloxone (2 mg/kg)-induced withdrawal hyperalgesia was also blocked by 100 mg/kg of naloxone. The blockage of withdrawal hyperalgesia by naloxone suggested the involvement of opioid receptors in the phenomenon and indicated that withdrawal hyperalgesia is a direct effect of a residual, low concentration of morphine. Acute experiments that show morphine- and naloxone-induced hyperalgesia further verified our hypothesis. Our findings offer a novel, alternative approach to opiate detoxifications that may prevent withdrawal symptoms by a complete blockage of the opioid receptors using a high dose of the opioid antagonist.

Contribution of UDP-Glucuronosyltransferase 1A1 and 1A8 to Morphine-6-Glucuronidation and Its Kinetic Properties

The metabolic conversion of morphine to morphine-6-glucuronide (M6G) seems to play a significant role in mediation of the clinical effect of morphine because of the superior analgesic effect of M6G. Therefore, it would be of great interest to clarify the specificity of morphine-6-glucuronidation by UDP glucuronosyltransferase (UGT) isozymes. We investigated the specificity of morphine-6-glucuronidation catalyzed by recombinant human UGT isozymes in microsomes from baculovirus-infected insect cells. The morphine glucuronidation activity of recombinant human UGT isozymes incubated with morphine and UDP-glucuronic acid was determined by high-performance liquid chromatography with a fluorescence detector. Not only UGT2B7, which is well known to catalyze morphine-6-glucuronidation, but also UGT1A1 and 1A8 effectively catalyzed morphine-6-glucuronidation at relatively low morphine concentrations (<100 muM). The kinetics of both isozymes at the low substrate concentrations showed hyperbolic Michaelis-Menten kinetics. However, as the morphine concentration approached 100 muM, morphine-6-glucuronidation activity gradually decreased, and the kinetics closely resembled substrate inhibition Michaelis-Menten kinetic behavior. The K(m) values were 67.9 and 68.1 muM and the K(si) values were 218.9 and 88.0 muM for UGT1A1 and 1A8, respectively. These kinetics are basically different from that of morphine-6-glucuronidation by UGT2B7, which suggested biphasic Michaelis-Menten kinetic behavior. Furthermore, to estimate the contribution of these UGT isozymes in M6G formation in vivo, the expression levels of UGT1A1 and 1A8 mRNA in human liver and intestine were determined by reverse transcription real-time polymerase chain reaction. The results strongly suggest that UGT1A1 and UGT1A8 are isozymes involved in morphine-6-glucuronidation in vivo, as is UGT2B7 in humans.