Molecular fingerprints of polar narcotic chemicals based on heterozygous essential gene knockout library in Saccharomyces cerevisiae.

Cytotoxicity of non-polar narcotic chemicals can be predicted by quantitative structure activity relationship (QSAR) models, but the polar narcotic chemicals' actual cytotoxicity exceeds the predicted values by their chemical structures. This discrepancy indicates that the molecular mechanism by which polar narcotic chemicals exert their toxicity is unclear. Taking advantage of Saccharomyces cerevisiae (yeast) functional genome-wide heterozygous essential gene knockout mutants, we here have identified the specific molecular fingerprints of two main chemical structure groups (phenols and anilines) of polar narcotic chemicals (dichlorophen (DCP), 4-chlorophenol (4-CP), 2, 4, 6-trichlorophenol (TCP), 3, 4-dichloroaniline (DCA) and N-methylaniline (NMA)) and one non-polar narcotic chemical 2, 2, 2-trichloroethanol (TCE). Especially, we identify 33, 57, 54, 46, 59 and 53 responsive strains through exposure to TCE, DCP, 4-CP, TCP, DCA and NMA with three test concentrations, respectively, revealing that these polar narcotic chemicals have more responsive strains than the non-polar narcotic chemical. Remarkably, we find that the molecular fingerprints of polar narcotic chemicals in different chemical structure groups are obviously varied, particularly phenols and anilines have their own specific molecular fingerprints. Interestingly, our results demonstrate that the molecular toxicity mechanisms of anilines are associated with DNA replication, but phenols are related with pathway of RNA degradation. Additionally, we find that the two knockout strains (SME1 and DIS3) and the three knockout strains (TSC11, RSP5 and HSF1) can specifically respond to exposure to phenols and anilines, respectively. Thus, they may be served as potential biomarkers to distinguish phenols from anilines. Collectively, our works demonstrate that the functional genomic platform of yeast essential gene mutants can not only act as an effective tool to identify key specific molecular fingerprints for polar narcotic chemicals, but also help to understand the molecular mechanisms of polar narcotic chemicals.

The Cannabinoid Receptor Type 1 Positive Allosteric Modulator ZCZ011 Attenuates Naloxone-Precipitated Diarrhea and Weight Loss in Oxycodone-Dependent Mice.

Opioid use disorder reflects a major public health crisis of morbidity and mortality in which opioid withdrawal often contributes to continued use. However, current medications that treat opioid withdrawal symptoms are limited by their abuse liability or lack of efficacy. Although cannabinoid 1 (CB1) receptor agonists, including Δ9-tetrahydrocannabinol, ameliorate opioid withdrawal in both clinical and preclinical studies of opioid dependence, this strategy elicits cannabimimetic side effects as well as tolerance and dependence after repeated administration. Alternatively, CB1 receptor positive allosteric modulators (PAMs) enhance CB1 receptor signaling and show efficacy in rodent models of pain and cannabinoid dependence but lack cannabimimetic side effects. We hypothesize that the CB1 receptor PAM ZCZ011 attenuates naloxone-precipitated withdrawal signs in opioid-dependent mice. Accordingly, male and female mice given an escalating dosing regimen of oxycodone, a widely prescribed opioid, and challenged with naloxone displayed withdrawal signs that included diarrhea, weight loss, jumping, paw flutters, and head shakes. ZCZ011 fully attenuated naloxone-precipitated withdrawal-induced diarrhea and weight loss and reduced paw flutters by approximately half, but its effects on head shakes were unreliable, and it did not affect jumping behavior. The antidiarrheal and anti-weight loss effects of ZCZ0111 were reversed by a CB1 not a cannabinoid receptor type 2 receptor antagonist and were absent in CB1 (-/-) mice, suggesting a necessary role of CB1 receptors. Collectively, these results indicate that ZCZ011 completely blocked naloxone-precipitated diarrhea and weight loss in oxycodone-dependent mice and suggest that CB1 receptor PAMs may offer a novel strategy to treat opioid dependence. SIGNIFICANCE STATEMENT: Opioid use disorder represents a serious public health crisis in which current medications used to treat withdrawal symptoms are limited by abuse liability and side effects. The CB1 receptor positive allosteric modulator (PAM) ZCZ011, which lacks overt cannabimimetic behavioral effects, ameliorated naloxone-precipitated withdrawal signs through a CB1 receptor mechanism of action in a mouse model of oxycodone dependence. These results suggest that CB1 receptor PAMs may represent a viable strategy to treat opioid withdrawal.

Clinical Pharmacology, Toxicity, and Abuse Potential of Opioids.

Opioids were the most common drug class resulting in overdose deaths in the United States in 2019. Widespread clinical use of prescription opioids for moderate to severe pain contributed to the ongoing opioid epidemic with the subsequent emergence of fentanyl-laced heroin. More potent analogues of fentanyl and structurally diverse opioid receptor agonists such as AH-7921 and MT-45 are fueling an increasingly diverse illicit opioid supply. Overdose from synthetic opioids with high binding affinities may not respond to a typical naloxone dose, thereby rendering autoinjectors less effective, requiring higher antagonist doses or resulting in a confusing clinical picture for health care providers. Nonscheduled opioid drugs such as loperamide and dextromethorphan are associated with dependence and risk of overdose as easier access makes them attractive to opioid users. Despite a common opioid-mediated pathway, several opioids present with unique pharmacodynamic properties leading to acute toxicity and dependence development. Pharmacokinetic considerations involve half-life of the parent opioid and its metabolites as well as resulting toxicity, as is established for tramadol, codeine, and oxycodone. Pharmacokinetic considerations, toxicities, and treatment approaches for notable opioids are reviewed.

Effects of alcohol on brain oxygenation and brain hypoxia induced by intravenous heroin.

Alcohol is the most commonly used psychoactive drug, often taken in conjunction with opioid drugs. Since both alcohol and opioids can induce CNS depression, it is often assumed that alcohol potentiates the known hypoxic effects of opioid drugs. To address this supposition, we used oxygen sensors to examine the effects of alcohol on brain oxygenation and hypoxic responses induced by intravenous heroin in awake, freely moving rats. To eliminate robust sensory effects of alcohol following its oral or intraperitoneal delivery, alcohol was administered directly into the stomach via chronically implanted intragastric catheters at human relevant doses. Alcohol delivered at a 0.5 g/kg dose did not affect brain oxygen levels, except for a weak transient increase during drug delivery. This phasic oxygen increase was stronger at a 2.0 g/kg alcohol dose and followed by a weaker tonic increase. Since alcohol absorption from intragastric delivery is much slower and more prolonged than with intraperitoneal or intravenous injections, the rapid rise of brain oxygen levels suggests that alcohol has a direct action on sensory afferents in the stomach well before the drug physically reaches brain tissue via circulation. Despite slow tonic increases in brain oxygen, alcohol at the 2.0 g/kg dose strongly potentiates heroin-induced oxygen responses, increasing both the magnitude and duration of oxygen decrease. Therefore, under the influence of alcohol, the use of opioid drugs becomes much more dangerous, increasing brain hypoxia and enhancing the probability of serious health complications, including coma and death.

Sex-specific transgenerational effects of adolescent morphine exposure on short-term memory and anxiety behavior: Male linage.

Current estimates indicate that opioid use and misuse are a rising epidemic, which presents a substantial socioeconomic burden around the world. Chronic opioid consumption, specifically during the critical period of adolescence, can lead to enduring effects not only in individuals but also in future generations. Utilizing rodent model, we have previously reported the impacts of paternal exposure to chronic morphine during adolescence on neurobehavioral features in progenies. Currently, the potential transgenerational effects of paternal morphine exposure during adolescence on anxiety-like behavior and short-term memory remains unknown. Male Wistar rats were exposed to increasing doses of morphine for ten days in adolescence (PND 30-39). Thereafter, following a 30-days drug-free period, the treated male rats mated with naïve females. The anxiety-like behavior and short-term memory performance were assessed in adult male and female offspring (PND 60) using open field and Y-maze tests. Both male and female progenies of morphine-treated sires revealed a significant reduction in the movement velocity compared to progenies of saline-treated sires as measured by open field test. Morphine-sired male but not female offspring also showed a non-significant large decreasing effect on time spent in the center and frequency of entries to the center of open field box. Moreover, a significant reduction in the number of entries and percent of time spent in the novel arm was observed in male and female morphine-sired offspring, as measured using Y-maze test. Growth outcomes also did not demonstrate any difference in the number of dam's fertility, pups birth, and death between morphine-sired and saline-sired groups in both sexes. Collectively, paternal exposure to morphine during adolescence induces sex-specific and selective disturbances in short-term memory while anxiety-like behavior was slightly disturbed.

Methocinnamox Reverses and Prevents Fentanyl-Induced Ventilatory Depression in Rats.

Opioid use disorder affects over 2 million Americans with an increasing number of deaths due to overdose from the synthetic opioid fentanyl and its analogs. The Food and Drug Administration-approved opioid receptor antagonist naloxone (e.g., Narcan) is used currently to treat overdose; however, a short duration of action limits its clinical utility. Methocinnamox (MCAM) is a long-lasting opioid receptor antagonist that may reverse and prevent the ventilatory-depressant effects of fentanyl. This study compared the ability of naloxone (0.0001-10 mg/kg) and MCAM (0.0001-10 mg/kg) to reverse and prevent ventilatory depression by fentanyl and compared the duration of action of MCAM intravenously and subcutaneously in two procedures: ventilation and warm-water tail withdrawal. In male Sprague-Dawley rats (N = 8), fentanyl (0.0032-0.178 mg/kg, i.v.) decreased minute volume in a dose- and time-dependent manner with a dose of 0.178 mg/kg decreasing VE to less than 40% of control. MCAM and naloxone reversed the ventilatory-depressant effects of 0.178 mg/kg fentanyl in a dose-related manner. The day after antagonist administration, MCAM but not naloxone attenuated the ventilatory-depressant effects of fentanyl. The duration of action of MCAM lasted up to 3 days and at least 2 weeks after intravenous and subcutaneous administration, respectively. MCAM attenuated the antinociceptive effects of fentanyl, with antagonism lasting up to 5 days and more than 2 weeks after intravenous and subcutaneous administration, respectively. Reversal and prolonged antagonism by MCAM might provide an effective treatment option for the opioid crisis, particularly toxicity from fentanyl and related highly potent analogs. SIGNIFICANCE STATEMENT: This study demonstrates that like naloxone, methocinnamox (MCAM) reverses the ventilatory-depressant effects of fentanyl in a time- and dose-related manner. However, unlike naloxone, the duration of action of MCAM was greater than 2 weeks when administered subcutaneously and up to 5 days when administered intravenously. These data suggest that MCAM might be particularly useful for rescuing individuals from opioid overdose, including fentanyl overdose, as well as protecting against the reemergence of ventilatory depression (renarconization).

A novel study for joint toxicity of typical aromatic compounds in coal pyrolysis wastewater by Tetrahymena thermophile.

The coal pyrolysis wastewater (CPW) contributed to aquatic environment contamination with amount of aromatic pollutants, and the research on joint toxicity of the mixture of aromatic compounds was vital for environmental protection. By using Tetrahymena thermophile as non-target organism, the joint toxicity of typical nonpolar narcotics and polar narcotics in CPW was investigated. The results demonstrated that the nonpolar narcotics exerted chronic and reversible toxicity by hydrophobicity-based membrane perturbation, while polar narcotics performed acute toxicity by irreversible damage of cells. As the most hydrophobic nonpolar narcotics, indole and naphthalene caused the highest joint toxicity in 24 h with the lowest EC50mix (24.93 mg/L). For phenolic compounds, the combination of p-cresol and p-nitrophenol also showed the top toxicity (EC50mix = 10.9 mg/L) with relation to high hydrophobicity, and the joint toxicity was obviously stronger and more acute than that of nonpolar narcotics. Furthermore, by studying the joint toxicity of nonpolar narcotics and polar narcotics, the hydrophobicity-based membrane perturbation was the first step of toxicity effects, and afterwards the acute toxicity induced by electrophilic polar substituents of phenols dominated joint toxicity afterwards. This toxicity investigation was critical for understanding universal and specific effects of CPW to aquatic organisms.

Computational and theoretical insights into the homeostatic response to the decreased cell size of midbrain dopamine neurons.

Midbrain dopamine neurons communicate signals of reward anticipation and attribution of salience. This capacity is distorted in heroin or cocaine abuse or in conditions such as human mania. A shared characteristic among rodent models of these behavioral disorders is that dopamine neurons in these animals acquired a small size and manifest an augmented spontaneous and burst activity. The biophysical mechanism underlying this increased excitation is currently unknown, but is believed to primarily follow from a substantial drop in K+ conductance secondary to morphology reduction. This work uses a dopamine neuron mathematical model to show, surprisingly, that under size diminution a reduction in K+ conductance is an adaptation that attempts to decrease cell excitability. The homeostatic response that preserves the intrinsic activity is the conservation of the ion channel density for each conductance; a result that is analytically demonstrated and challenges the experimentalist tendency to reduce intrinsic excitation to K+ conductance expression level. Another unexpected mechanism that buffers the raise in intrinsic activity is the presence of the ether-a-go-go-related gen K+ channel since its activation is illustrated to increase with size reduction. Computational experiments finally demonstrate that size attenuation results in the paradoxical enhancement of afferent-driven bursting as a reduced temporal summation indexed correlates with improved depolarization. This work illustrates, on the whole, that experimentation in the absence of mathematical models may lead to the erroneous interpretation of the counterintuitive aspects of empirical data.

Codeine exerts cardiorenal injury via upregulation of adenine deaminase/xanthine oxidase and caspase 3 signaling.

AIMS: Codeine treatment has been shown to be associated with glucolipid deregulation, though data reporting this are inconsistent and the mechanisms are not well understood. Perturbation of glutathione-dependent antioxidant defense and adenosine deaminase (ADA)/xanthine oxidase (XO) signaling has been implicated in the pathogenesis of cardiometabolic disorders. We thus, hypothesized that depletion of glutathione contents and upregulation of ADA/XO are involved in codeine-induced glucolipid deregulation. The present study also investigated whether or not codeine administration would induce genotoxicity and apoptosis in cardiac and renal tissues. MATERIALS AND METHODS: Male New Zealand rabbits received per os distilled water or codeine, either in low dose (4 mg/kg) or high dose (10 mg/kg) for 6 weeks. KEY FINDINGS: Codeine treatment led to reduced absolute and relative cardiac and renal mass independent of body weight change, increased blood glucose, total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL-C), as well as increased atherogenic indices and triglyceride-glucose index (TyG). Codeine administration significantly increased markers of cardiac and renal injury, as well as impaired cardiorenal functions. Codeine treatment also resulted in increased cardiac and renal malondialdehyde, Advanced Glycation Endproducts (AGE) and 8-hydroxydeoxyguanosine (8-OH-dG), and myeloperoxidase (MPO), ADA, XO, and caspase 3 activities. These observations were accompanied by impaired activities of cardiac and renal proton pumps. SIGNIFICANCE: Findings of this study demonstrate that upregulation of ADA/XO and caspase 3 signaling are, at least partly, contributory to the glucolipid deregulation and cardiorenal injury induced by codeine.

Cocaine added to heroin fails to affect heroin-induced brain hypoxia.

Heroin and cocaine are both highly addictive drugs that cause unique physiological and behavioral effects. These drugs are often co-administered and cocaine has been found in ~20% of cases of opioid overdose death. Respiratory depression followed by brain hypoxia is the most dangerous effect of high-dose opioids that could result in coma and even death. Conversely, cocaine at optimal self-administering doses increases brain oxygen levels. Considering these differences, it is unclear what pattern of oxygen changes will occur when these drugs are co-administered. Here, we used high-speed amperometry with oxygen sensors to examine changes in oxygen concentrations in the nucleus accumbens (NAc) induced by intravenous (iv) cocaine, heroin, and their mixtures in freely-moving rats. Cocaine delivered at a range of doses, both below (0.25 mg/kg) and within the optimal range of self-administration (0.5 and 1.0 mg/kg) modestly increased NAc oxygen levels. In contrast, heroin increased oxygen levels at a low reinforcing dose (0.05 mg/kg), but induced a biphasic down-up change at higher reinforcing doses (0.1 and 0.2 mg/kg), and caused a strong monophasic oxygen decrease during overdose (0.6 mg/kg). When combined at moderate doses, cocaine (0.25, 0.5 mg/kg) slightly increased and prolonged oxygen increases induced by heroin alone (0.5 and 0.1 mg/kg), but oxygen decreases were identical when cocaine (1 mg/kg) was combined with heroin at large doses (0.2 and 0.6 mg/kg). Therefore, health dangers of speedball may result from de-compensation of vital functions due to diminished intra-brain oxygen inflow induced by high-dose heroin coupled with enhanced oxygen use induced by cocaine.

Effects of tramadol administration on male reproductive toxicity in Wistar rats The role of oxidative stress, mitochondrial dysfunction, apoptosis-related gene expression, and nuclear factor kappa B signalling.

AIM: The present study investigated the role of redox balance, inflammation, mitochondrial dysfunction, and apoptosis in Tramadol (Tra)-induced testicular toxicity. METHOD: Twenty-four male Wistar rats were randomly divided into either the control group or the groups receiving different doses of Tra (25, 50, and 75 mg/kg/day, i.p.) for 21 successive days. Testicular tissues were collected for oxidative stress, mitochondrial function, sperm assays and histopathological evaluation. Real-time polymerase chain reaction was performed to evaluate the markers of inflammation and apoptosis. RESULTS: Tra caused a significant reduction in the sperm count, motility and morphology, while it caused a marked increase in oxidative stress parameters. In addition, Tra induced testicular mitochondrial dysfunction due to the collapse of mitochondrial membrane potential and mitochondrial swelling. It also led to the significant inhibition of anti-apoptotic Bcl-2 expression, besides a significant increase in pro-apoptotic Bax expression. There was a significant increase in the level of tumour necrosis factor-α, interlukin-1ß and nuclear factor kappa B. Histopathological degenerative changes were observed in the testis after Tra exposure. CONCLUSIONS: The present results suggest that Tra exposure may lead to reproductive toxicity due to the loss of the antioxidant defence system, mitochondrial dysfunction, and activation of inflammatory and apoptotic pathways (Tab. 4, Fig. 5, Ref. 63).

Poikilocytosis and tissue damage as negative impacts of tramadol on juvenile of Tilapia (Oreochromis niloticus).

Pharmaceuticals residue was detected in the water bodies as a consequence of the incomplete treatment. Recently, the side impacts of that residue on aquatic creatures have received a considerable attention. However, there is insufficient information about the effect of the most consumed narcotic drug (tramadol) on fish as an aquatic model. Thus, this study aims at investigating the poikilocytosis and tissue damage in Oreochromis niloticus after the exposure to 100 and 200 mg/L of tramadol hydrochloride. Three groups of fish were used; one as a control group, and the other two groups were exposed to 100 mg/L and 200 mg/L of tramadol hydrochloride respectively for 25 days. Exposure to tramadol caused a significant increase in the percentage of poikilocytosis compared to the control group. Poikilocytosis included tear-drop cell, spindle-shaped cell, sickle cell, schistocyte, blebbed cell, acanthocyte, eccentric nucleus, amoebocyte, dividing cell, and crenated cell. Moreover, liver tissue in fish exposed to tramadol showed degeneration and vacuolization of hepatocytes and atrophy of pancreatic acini as signs of histopathological alterations. Histopathological changes of brain showed severe gliosis, dark neurons, and vacuolization in fish exposed to tramadol compared to control fish. Gills tissue showed erosion, epithelial lifting, and secondary lamellae shrinking in fish exposed to tramadol compared to control fish. In conclusion, tramadol induced histopathological changes in liver, brain, and gills of Oreochromis niloticus as well as poikilocytosis were indicated clearly. Therefore, tramadol leakage to waters should be avoided to preserve aquatic creatures.

Codeine-induced sperm DNA damage is mediated predominantly by oxidative stress rather than apoptosis.

ABSTRACTBackground: Opioids have been implicated to induce infertility. Although codeine remains the most used opioid for recreational purpose, no study has documented its effect on sperm quality. Elucidating the effect of codeine on sperm cells and the associated mechanisms may provide an insight into preventing drug-induced sperm damage. Twenty-one New Zealand white rabbits were randomized into three groups; control and codeine-treated. The codeine-treated groups received either 4 or 10mg/kg b.w of codeine for six weeks.Results: Codeine treatment led to significant decrease in sperm count, motility, viability, normal morphology, and sperm membrane integrity. This was associated with significant rise in sperm DNA fragmentation, oxidative damage, and caspase 3 activity. The percentage of sperm DNA fragmentation correlates positively with 8-hydroxy-2'-deoxyguanosine, a biomarker of oxidative DNA damage, and caspase 3 activity, a biomarker of apoptosis. The observed correlation was stronger between sperm DNA fragmentation and oxidative DNA damage than sperm DNA fragmentation and caspase 3 activity.Conclusion: This study revealed that chronic codeine exposure causes sperm DNA fragmentation and poor sperm quality primarily via oxidative stress rather than activation of caspase 3-dependent apoptosis. Findings of the present study may explain drug-induced male factor infertility, particularly, those associated with opioid use.

Assessment of sexual behaviour and fertility indices in male rabbits following chronic codeine use.

BACKGROUND: Codeine is the latest trend of drug abuse, particularly in Nigeria and regarded as the gateway to the abuse of other substances. OBJECTIVES: The present study examined the effects of graded doses of codeine on sexual behaviour and fertility profile. MATERIALS AND METHODS: Rabbits were either administered normal saline (0.2 mL), 4mg/kg b.w of codeine (low dose), or 10mg/kg b.w of codeine (high dose) p.o for 6 weeks. RESULTS AND DISCUSSION: Findings of the study showed that codeine administration significantly increased libido as witnessed by significantly short mount latency (ML), intromission latency (IL), post-ejaculatory interval (PEI) and significantly increased mount frequency (MF), intromission frequency (IF) and ejaculation latency (EL). Furthermore, codeine caused a marked rise in penile reflexes evident by a significant increase in erections, quick flips, long flips and total penile reflexes. However, copulatory efficiency and fertility index were significantly lower in codeine-treated groups when compared with the control. Serum levels of testosterone were also significantly lower in the treated groups. CONCLUSIONS: The present study demonstrates that codeine-induced enhancement of sexual performance is via a testosterone-independent mechanism. It also reveals that although codeine enhances copulatory locomotor activity, it is a potential risk factor for infertility.

A quantitative structure-activity relationships approach to predict the toxicity of narcotic compounds to aquatic communities.

Species may vary markedly in terms of their sensitivity to toxicants, and such variation can be described through the species sensitivity distribution (SSD) approach. Using SSD cumulative functions, it is possible to calculate the hazardous concentration for 5% of the species (HC5), namely the contaminant concentration at which 5% of species will be affected. HC5 is often utilised to derive the predicted no-effect concentration, or the concentration at which a chemical will likely have no toxic effects on the different species present in an ecosystem. However, the lack of sufficient ecotoxicological data frequently obstructs the derivation of SSD curves and consequently the HC5. In the last 30 years, quantitative structure-activity relationship (QSAR) models have been widely used to predict the toxicity of chemicals to single species. The aim of this study was to evaluate the possibility of extending the applicability domain of these models from single species to the community level by predicting the HC5 values for aquatic communities and bypassing the need to derive SSD curves. This approach's practical advantage is that it would allow information on the toxicity of contaminants to be obtained on a hierarchical scale (aquatic community), which is ecologically more relevant than on the scale of single species, without the need for a robust toxicity data set. In the first part of the study, two simple QSAR models were developed for narcotic and polar narcotic compounds. Then, the QSAR model developed for narcotic compounds was utilised to define the baseline toxicity for aquatic communities and to calculate the toxicity ratios for various specifically acting compounds (insecticides and herbicides).

Testing for midazolam and oxycodone in blood after formalin-embalmment: About a complex medico-legal case.

The stability of compounds in formalin solution is an important factor for drug analysis in a toxicological investigation. In this article, the authors report a complex medico-legal case involving midazolam and oxycodone. The complexity of this case comes from the fact that the body was embalmed with formalin solution before the autopsy. This technique, called thanatopraxy, allows the preservation of corpses from decomposition, the destruction of a maximal number of micro-organisms, and the presentation of the body with a natural appearance to the family. Unfortunately, when thanatopraxy is performed before the collection of biological specimens, the toxicological results are not representative of the time of the death. In addition, the interpretation of the results is difficult, because formalin can cause oxidation of xenobiotics present in the body at the time of the death, alter the pH of the tissues and dilute the compounds. To document the chemical stability of midazolam and oxycodone in formalin solution and interpret the results, a stability study was conducted for 21 days. Blood containing midazolam and oxycodone was spiked with formalin, kept at 4°C and regularly tested for both drugs. This study showed a rapid degradation of midazolam and oxycodone (85% during the first 24 hours for oxycodone). In the peripheral blood of the victim, methanol (1.31 g/L), midazolam (74ng/mL) and oxycodone (152 ng/mL) were identified. According to the stability study, the measured concentrations in formalin fixed-tissues are to be interpreted very carefully, knowing that significant degradation has occurred.

Acute and repeated administration of MDPV increases aggressive behavior in mice: forensic implications.

MDPV is a synthetic cathinone illegally marketed and consumed for its psychostimulant effects, which are similar to those produced by cocaine, amphetamines, and MDMA. Clinical reports indicate that MDPV produces euphoria, increases alertness, and at high doses causes agitation, psychosis, tachycardia and hypertension, hallucinations, delirium, hyperthermia, rhabdomyolysis, and even death. In rodents, MDPV reproduces the typical physiological effects of psychostimulant drugs, demonstrating greater potency than cocaine. Nevertheless, its role in aggressive behavior has been reported but not yet experimentally confirmed. Therefore, the aim of this study was to evaluate the effects of acute and repeated MDPV (0.01-10 mg/kg i.p.) administration on aggressive behavior in mice and to compare them with those of cocaine (0.01-10 mg/kg i.p.) administration. To this purpose, the resident-intruder test in isolated mice and the spontaneous and stimulated aggressiveness tests for group-housed mice were employed. The present study shows for the first time that MDPV enhances aggressive behavior and locomotion in mice with greater potency and efficacy than cocaine treatment. Moreover, the aggressive and locomotor responses are enhanced after repeated administration, indicating that a sensitization mechanism comes into play. These results, although from preclinical investigation, are suggestive that human MDPV intake could be a problem for public health and the criminal justice system. Thus, investigation by police officers and medical staff is needed to prevent interpersonal violence induced by the consumption of synthetic cathinones.

Determination of narcotic potency using a neurobehavioral assay with larval zebrafish.

BACKGROUND: Identifying chemicals with narcotic potency is an important aspect of assessing the safety of consumer products that may be accidentally ingested. A rapid and efficient assay of narcotic potency is desired for assessing chemicals with such suspected activity. OBJECTIVES: This purpose of this research was to develop a non-mammalian vertebrate, high throughput, neurobehavioral method to assess the narcotic potency of chemicals using larval zebrafish. METHODS: Larval zebrafish were acutely exposed to chemicals beginning at 5 days post fertilization (5 dpf). Locomotor activity, elicited by regular, periodic photostimulation, was quantified using a video tracking apparatus. Narcotic potency was determined as the molar concentration at which photostimulated locomotor activity was reduced by 50% (IC50). Toxicity was assessed based on observations of morbidity or mortality. Recovery was assessed following removal of test material by serial dilution and reassessment of photostimulated behavior 24 hr later (6 dpf). RESULTS: A total of 21 chemicals were assessed. Etomidate, a human narcotic analgesic agent, was used as a reference material. Investigating a series of eleven linear, primary alcohols (C6 to C16), a relationship between narcotic potency and carbon number was observed; narcotic potency increased with carbon number up to C12, consistent with historical studies. For a set of technical grade surfactants, nonionic surfactants (i.e., alcohol ethoxylates) were observed to be narcotic agents while anionic surfactants produced evidence of reduced locomotor activity only in combination with toxicity. Of the solvents evaluated, only ethanol exhibited narcotic activity with an IC50 of 261 mM and was the least potent of the chemicals investigated. Etomidate was the most potent material evaluated with an IC50 of 0.39 µM. CONCLUSIONS: The larval zebrafish neurobehavioral assay provides a method capable of estimating the narcotic potency of chemicals and can identify if toxicity contributes to observed neurobehavioral effects in the test organism.

Exploring inter-species sensitivity to a model hydrocarbon, 2-Methylnaphtalene, using a process-based model.

We compared inter-species sensitivity to a model narcotic compound, 2-Methylnaphthalene, to test if taxonomical relatedness, feeding guilds, and trophic level govern species sensitivities on species distributed in different regions. We fitted a toxicokinetic-toxicodynamic model to survival patterns over time for 26 species using new and raw data from the literature. Species sensitivity distributions provided little insight into understanding patterns in inter-species sensitivity. The range of no-effect concentrations (NEC) obtained for 26 species showed little variation (mean 0.0081 mM; SD 0.009). Results suggest that the NEC alone does not explain the complexity of the species tolerances. The dominant rate constant and the derived time to observe an effect (t0), a function of concentration, might provide the means for depicting patterns in sensitivity and better ecotoxicological testing. When comparing the t0 functions, we observed that Arctic species have shorter time frames to start showing effects. Mollusks and second trophic level species took longer to build up a lethal body burden than the rest. Coupling our results with fate and transport models would allow forecasting narcotic compounds toxicity in time and thus improve risk assessment.

Zebrafish embryo and acute fish toxicity test show similar sensitivity for narcotic compounds.

The zebrafish embryo test has been discussed as an alternative test system to provide data on acute fish toxicity required by diverse regulations. A meta-analysis of zebrafish embryo acute toxicity (ZFET) data has revealed conflicting evidence that narcotic compounds (i.e. compounds with baseline toxicity) may exhibit weaker sensitivity in the ZFET if compared to the acute (adult) fish toxicity test (AFT). Therefore, six compounds with presumably narcotic or unknown mode of action, and for which a previous meta-analysis has indicated weaker sensitivity were experimentally analysed for their fish embryo acute toxicity and exposure concentrations were monitored. The data indicated that ZFET and AFT for the selected compounds revealed similar sensitivity and differences were in the range of species differences of the AFT.