In vitro and in vivo stability of a highly efficient long-acting cocaine hydrolase.

It is recognized as a promising therapeutic strategy for cocaine use disorder to develop an efficient enzyme which can rapidly convert cocaine to physiologically inactive metabolites. We have designed and discovered a series of highly efficient cocaine hydrolases, including CocH5-Fc(M6) which is the currently known as the most efficient cocaine hydrolase with both the highest catalytic activity against (-)-cocaine and the longest biological half-life in rats. In the present study, we characterized the time courses of protein appearance, pH, structural integrity, and catalytic activity against cocaine in vitro and in vivo of a CocH5-Fc(M6) bulk drug substance produced in a bioreactor for its in vitro and in vivo stability after long-time storage under various temperatures (- 80, - 20, 4, 25, or 37 °C). Specifically, all the tested properties of the CocH5-Fc(M6) protein did not significantly change after the protein was stored at any of four temperatures including - 80, - 20, 4, and 25 °C for ~ 18 months. In comparison, at 37 °C, the protein was less stable, with a half-life of ~ 82 days for cocaine hydrolysis activity. Additionally, the in vivo studies further confirmed the linear elimination PK profile of CocH5-Fc(M6) with an elimination half-life of ~ 9 days. All the in vitro and in vivo data on the efficacy and stability of CocH5-Fc(M6) have consistently demonstrated that CocH5-Fc(M6) has the desired in vitro and in vivo stability as a promising therapeutic candidate for treatment of cocaine use disorder.

Nucleus accumbens neuronal ensembles vary with cocaine reinforcement in male and female rats.

Neuronal ensembles in the medial prefrontal cortex mediate cocaine self-administration via projections to the nucleus accumbens. We have recently shown that neuronal ensembles in the prelimbic cortex form rapidly to mediate cocaine self-administration. However, the role of neuronal ensembles within the nucleus accumbens in initial cocaine-seeking behaviour remains unknown. Here, we sought to expand the current literature by testing the necessity of the cocaine self-administration ensemble in the nucleus accumbens core (NAcCore) 1 day after male and female rats acquire cocaine self-administration by using the Daun02 inactivation procedure. We found that disrupting the NAcCore ensembles after a no-cocaine reward-seeking test increased subsequent cocaine seeking, while disrupting NAcCore ensembles following a cocaine self-administration session decreased subsequent cocaine seeking. We then characterized neuronal cell type in the NAcCore using RNAscope in situ hybridization. In the no-cocaine session, we saw reduced dopamine D1 type neuronal activation, while in the cocaine self-administration session, we found preferential dopamine D1 type neuronal activity in the NAcCore.

Prior cocaine self-administration does not impair the ability to delay gratification in rats during diminishing returns.

Previous exposure to drugs of abuse produces impairments in studies of reversal learning, delay discounting and response inhibition tasks. While these studies contribute to the understanding of normal decision-making and how it is impaired by drugs of abuse, they do not fully capture how decision-making impacts the ability to delay gratification for greater long-term benefit. To address this issue, we used a diminishing returns task to study decision-making in rats that had previously self-administered cocaine. This task was designed to test the ability of the rat to choose to delay gratification in the short-term to obtain more reward over the course of the entire behavioral session. Rats were presented with two choices. One choice had a fixed amount of time delay needed to obtain reward [i.e. fixed delay (FD)], while the other choice had a progressive delay (PD) that started at 0 s and progressively increased by 1 s each time the PD option was selected. During the 'reset' variation of the task, rats could choose the FD option to reset the time delay associated with the PD option. Consistent with previous results, we found that prior cocaine exposure reduced rats' overall preference for the PD option in post-task reversal testing during 'no-reset' sessions, suggesting that cocaine exposure made rats more sensitive to the increasing delay of the PD option. Surprisingly, however, we found that rats that had self-administered cocaine 1-month prior, adapted behavior during 'reset' sessions by delaying gratification to obtain more reward in the long run similar to control rats.

Drogas de abuso asociadas a las intoxicaciones agudas: descripción global y análisis de las diferencias en mujeres atendidas en el servicio de urgencias / Street drugs associated with acute poisoning: description and analysis of differences in women attended in a hospital emergency department

Objetivos. La prevalencia del uso de drogas de abuso es difícil de establecer en mujeres, debido a los estigmas asociados a ello. El objetivo principal fue analizar las posibles diferencias de las intoxicaciones agudas (IA) según el sexo en una muestra de pacientes atendidos en dos servicios de urgencias hospitalarios (SUH). El objetivo secundario fue identificar las variables asociadas a las intoxicaciones graves, definidas de forma arbitraria como las que requerían una atención intensiva médica de más de 12 horas y posterior ingreso hospitalario. Métodos. Estudio retrospectivo en dos SUH que incluyeron pacientes mayores de 18 años atendidos por IA por drogas de abuso, en el periodo comprendido entre el 1 de julio 2020 y el 31 de julio 2023. Se recogieron variables epidemiológicas, clínicas y de laboratorio. Resultados. Se incluyeron 1.032 pacientes, un 18,5% (191) mujeres. La edad media fue de 35 (DE 10) años, con elevada prevalencia de enfermedad mental aguda (32,2%) e infección por VIH (35,7%). El principal motivo de consumo fue lúdico (90,9%). Las principales drogas de abuso fueron cocaína, alcohol y metanfetaminas. El análisis multivariado mostró que únicamente la edad (OR: 1,03, IC 95%: 1,01-1,05, p = 0,003), el VIH (OR: 2,10, IC 95%: 1,29-3,41, p = 0,003), el consumo de benzodiacepinas (OR: 3,48, IC 95%: 2,14-5,66, p < 0,0001), y la ideación autolítica (OR: 1,82, IC 95%: 1,25-3,79, p = 0,004), se asociaron a gravedad de la intoxicación. Conclusiones. Las IA por drogas de abuso en mujeres presentan algunas diferencias en relación a las de los hombres, ya que son más jóvenes y asocian consumo de alcohol con mayor frecuencia. Las campañas de prevención y políticas sanitarias sobre el uso de sustancias deberían tener en cuenta las diferencias en el consumo según el sexo para adaptarlas a la población a las que vayan dirigidas. (AU)

Background. The prevalence of street drug abuse is difficult to establish in women because of stigma associated withthe practice. The main objective of this study was to analyze possible differences between men and women in a sample of patients attended for emergencies due to acute poisonings. The secondary aim was to identify variables associated with severe poisonings defined arbitrarily as requiring intensive care for more than 12 hours after hospital admission. Methods. Retrospective study in 2 hospital EDs. We included patients over the age of 18 years attended for street drug poisonings between July 1, 2020, and July 31, 2023. Epidemiologic, clinical, and laboratory variables were analyzed. Results. A total of 1032 patients were studied; 191 (18.5%) were women. The mean (SD) age was 35 years, and the prevalences of acute mental illness and HIV infection were high at 32.2% and 35.7%, respectively. Drug use was recreational in most cases (90.9%). Cocaine, alcohol, and methamphetamines were the substances most often used. Multivariate analysis showed that the factors associated with the seriousness of poisoning were age, with an odds ratio (OR) of 1.03 (95% CI, 1.01-1.05; P = .003); HIV (OR, 2.10; 95% CI, 1.29-3.41; P = .003); use of benzodiazepines (OR, 3.48; 95% CI, 2.14-5.66; P < .0001); and suicidal ideations (OR, 1.82; 95% CI, 1.25-3.79; P = .004). Conclusions. Differences in poisoning characteristics in women were found, probably related to the younger ages of men in the sample and their higher frequency of alcohol consumption. Public health policies and campaigns to prevent drug abuse should take gender differences into consideration in order to adapt messages to the target populations. (AU)

Estimated Number of Injection-Involved Overdose Deaths in US States From 2000 to 2020: Secondary Analysis of Surveillance Data.

BACKGROUND: In the United States, both drug overdose mortality and injection-involved drug overdose mortality have increased nationally over the past 25 years. Despite documented geographic differences in overdose mortality and substances implicated in overdose mortality trends, injection-involved overdose mortality has not been summarized at a subnational level. OBJECTIVE: We aimed to estimate the annual number of injection-involved overdose deaths in each US state from 2000 to 2020. METHODS: We conducted a stratified analysis that used data from drug treatment admissions (Treatment Episodes Data Set-Admissions; TEDS-A) and the National Vital Statistics System (NVSS) to estimate state-specific percentages of reported drug overdose deaths that were injection-involved from 2000 to 2020. TEDS-A collects data on the route of administration and the type of substance used upon treatment admission. We used these data to calculate the percentage of reported injections for each drug type by demographic group (race or ethnicity, sex, and age group), year, and state. Additionally, using NVSS mortality data, the annual number of overdose deaths involving selected drug types was identified by the following specific multiple-cause-of-death codes: heroin or synthetic opioids other than methadone (T40.1, T40.4), natural or semisynthetic opioids and methadone (T40.2, T40.3), cocaine (T40.5), psychostimulants with abuse potential (T43.6), sedatives (T42.3, T42.4), and others (T36-T59.0). We used the probabilities of injection with the annual number of overdose deaths, by year, primary substance, and demographic groups to estimate the number of overdose deaths that were injection-involved. RESULTS: In 2020, there were 91,071 overdose deaths among adults recorded in the United States, and 93.1% (84,753/91,071) occurred in the 46 jurisdictions that reported data to TEDS-A. Slightly less than half (38,253/84,753, 45.1%; 95% CI 41.1%-49.8%) of those overdose deaths were estimated to be injection-involved, translating to 38,253 (95% CI 34,839-42,181) injection-involved overdose deaths in 2020. There was large variation among states in the estimated injection-involved overdose death rate (median 14.72, range 5.45-31.77 per 100,000 people). The national injection-involved overdose death rate increased by 323% (95% CI 255%-391%) from 2010 (3.78, 95% CI 3.33-4.31) to 2020 (15.97, 95% CI 14.55-17.61). States in which the estimated injection-involved overdose death rate increased faster than the national average were disproportionately concentrated in the Northeast region. CONCLUSIONS: Although overdose mortality and injection-involved overdose mortality have increased dramatically across the country, these trends have been more pronounced in some regions. A better understanding of state-level trends in injection-involved mortality can inform the prioritization of public health strategies that aim to reduce overdose mortality and prevent downstream consequences of injection drug use.

Prenatal and postnatal cocaine exposure enhances the anxiety- and depression-like behaviors in rats during cocaine withdrawal.

Prenatal drug exposure is a public health problem, which results in profound behavioral problems during childhood and adolescence, mainly represented by an increase in the risk of cocaine abuse at an early age. In rodents, prenatal and postnatal cocaine exposure enhanced locomotor activity and cocaine- or nicotine-induced locomotor sensitization. Various authors consider that the adverse emotional states (anxiety and depression) that occur during cocaine withdrawal are the main factors that precipitate, relapse, and increase chronic cocaine abuse, which could increase the risk of relapse of cocaine abuse. Therefore, the objective of this study was to characterize anxiety- and depression-like behaviors at different times (30, 60, 90, and 120 days) of cocaine withdrawal in rats born to females exposed prenatally and postnatally to cocaine. A group of pregnant female Wistar rats were administered daily from day GD0 to GD21 with cocaine (cocaine preexposure group), and another group of pregnant female rats was administered daily with saline (saline preexposure group). Of the litters resulting from the cocaine-pre-exposed and saline-pre-exposed pregnant female groups, only the male rats were used for the recording of the anxiety- and depression-like behaviors at different times (30, 60, 90, and 120 days) of cocaine withdrawal The study found that prenatal and postnatal cocaine exposure dose-dependent enhanced anxiety- and depression-like behaviors. This suggests that prenatal and postnatal cocaine exposure can result in enhanced vulnerability to cocaine abuse in young and adult humans.

Indirect and direct cannabinoid agonists differentially affect mesolimbic dopamine release and related behaviors.

The cannabinoid system is being researched as a potential pharmaceutical target for a multitude of disorders. The present study examined the effect of indirect and direct cannabinoid agonists on mesolimbic dopamine release and related behaviors in C57BL/6J (B6) mice. The indirect cannabinoid agonist N-arachidonoyl serotonin (AA-5-HT) indirectly agonizes the cannabinoid system by preventing the metabolism of endocannabinoids through fatty acid amide hydrolase inhibition while also inhibiting transient receptor potential vanilloid Type 1 channels. Effects of AA-5-HT were compared with the direct cannabinoid receptor Type 1 agonist arachidonoyl-2'-chloroethylamide (ACEA). In Experiment 1, mice were pretreated with seven daily injections of AA-5-HT, ACEA, or vehicle prior to assessments of locomotor activity using open field (OF) testing and phasic dopamine release using in vivo fixed potential amperometry. Chronic exposure to AA-5-HT did not alter locomotor activity or mesolimbic dopamine functioning. Chronic exposure to ACEA decreased rearing and decreased phasic dopamine release while increasing the dopaminergic response to cocaine. In Experiment 2, mice underwent AA-5-HT, ACEA, or vehicle conditioned place preference, then saccharin preference testing, a measure commonly associated with anhedonia. Mice did not develop a conditioned place preference or aversion for AA-5-HT or ACEA, and repeated exposure to AA-5-HT or ACEA did not alter saccharin preference. Altogether, the findings suggest that neither of these drugs induce behaviors that are classically associated with abuse liability in mice; however, direct cannabinoid receptor Type 1 agonism may play more of a role in mediating mesolimbic dopamine functioning than indirect cannabinoid agonism. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Granulomatosis with polyangiitis or its mimic? A case report.

Differentiation between granulomatosis with polyangiitis (GPA) limited to the upper airways and cocaine-induced midline destructive lesion (CIMDL) may be particularly difficult because of their common histopathologic features and antineutrophil cytoplasmic antibody (ANCA) profiles. We herein present a case involving a young woman with an initial diagnosis of GPA based on upper and lower airway manifestations and constitutional symptoms, histopathologic evidence of granulomas, a positive cytoplasmic ANCA indirect immunofluorescent test result, and proteinase 3 positivity by enzyme-linked immunosorbent assay (ELISA). CIMDL was confirmed based on the appearance of a hard palate perforation, positivity for methylecgonine on urine toxicology, a positive perinuclear ANCA indirect immunofluorescent test result, and subsequent human neutrophil elastase (HNE) ANCA positivity by ELISA. Finally, based on the coexistence of CIMDL, constitutional symptoms, and lower airway manifestations, the diagnosis was modified to cocaine-induced GPA mimic. Urine toxicology for cocaine and HNE ELISA are indicated in young patients with GPA who develop limited airway disease to check for the presence of CIMDL and cocaine-/levamisole-induced ANCA-associated vasculitis. Continued abstinence from cocaine is the first-choice therapy for both CIMDL and cocaine-induced GPA mimic.

Prehistoric or current primitive cranial operations.

Humankind demonstrates boundless curiosity, mostly expressed through the activities of a small number of individuals, whose achievements affect all members of society. The extent and distribution of pre-historic trepanation and trepanation in contemporary unsophisticated societies are reviewed. In the great majority of cases the intention of trepanation has been therapeutic, even if the understanding of underlying pathophysiology is not the same as that which scientific societies now accept. This review demonstrates variation in surgical technique. In the Atlas Mountains it was unacceptable to operate on the cranial sutures whereas in New Ireland it was not important. Pain relief was unnecessary in Melanesia because the patients were largely unconscious following injury. In South America, there was access to the coca leaf which could help with pain relief. In East Africa, one patient described the application of a powder to his wound which was thought to be for pain relief. The nature of the powder remains unknown. There were differences in the indications for trepanation. In New Britain, the operation was performed only for cases of fracture. In nearby New Ireland, epilepsy and certain forms of mental disturbance were also indications. In North and East Africa, the indication was most frequently headache following trauma. Most of these trepanations did not involve drilling, which is the main subject of this book.

Clavulanic Acid Decreases Cocaine Cue Reactivity in Addiction-Related Brain Areas, a Randomized fMRI Pilot Study.

Background: Preclinical studies show that clavulanic acid (CLAV) inhibits cocaine self-administration. This study investigates the effect of CLAV on regions of brain activation in response to cocaine cues during functional magnetic resonance imaging (fMRI) in participants with cocaine use disorder (CUD). Methods: A double-masked, placebo-controlled clinical trial with thirteen individuals with severe CUD who were randomized to treatment with CLAV (N = 10, 9 completers) 500 mg/day or matched placebo (PBO) (N = 3) for 3 days. fMRI was used to assess brain reactivity to 18 alternating six-second video clips of cocaine or neutral scenes. In this paradigm, participants were exposed to three different stimulus conditions: NEUTRAL, WATCH (passive watching), and DOWN (actively inhibiting craving while watching). Results: Participants who received CLAV demonstrated a significant reduction in brain activity in the anterior cingulate gyrus (p = 0.009) and the caudate (p = 0.018) in response to DOWN cocaine cues. There was a trend toward lessened cue reactivity in other regions implicated in CUD. Conclusion: CLAV reduced the response of the brain regions associated with motivation and emotional response during the DOWN condition compared to PBO, suggesting CLAV may strengthen voluntary efforts to avoid cocaine use. This pilot data supports the use of CLAV for CUD. (Trial registered in ClinicalTrials.gov NCT04411914).

Headache Attributed to a Substance or Its Withdrawal.

Identification of substances that may cause or trigger headache is important to start effective treatment early to prevent unnecessary suffering, deterioration in quality of life, and the development of chronic pain. Treatment in case of medication overuse and other chronic headache should be decisive and effective. Drug withdrawal and introduction of effective prophylactic medication for the underlying headache disorder should be the primary treatment strategy. Typical headache-inducing substances are nitric oxide, phosphodiesterase, cocaine, alcohol, histamine, carbon oxide, and calcitonin gene-related peptide. The withdrawal of caffeine, estrogen, and opioids is most often associated with the development of headache.

Impact of cannabidiol on brain glucose metabolism of C57Bl/6 male mice previously exposed to cocaine.

Despite evidence of the beneficial effects of cannabidiol (CBD) in animal models of cocaine use disorder (CUD), CBD neuronal mechanisms remain poorly understood. This study investigated the effects of CBD treatment on brain glucose metabolism, in a CUD animal model, using [18F]FDG positron emission tomography (PET). Male C57Bl/6 mice were injected with cocaine (20 mg/kg, i.p.) every other day for 9 days, followed by 8 days of CBD administration (30 mg/kg, i.p.). After 48 h, animals were challenged with cocaine. Control animals received saline/vehicle. [18F]FDG PET was performed at four time points: baseline, last day of sensitization, last day of withdrawal/CBD treatment, and challenge. Subsequently, the animals were euthanized and immunohistochemistry was performed on the hippocampus and amygdala to assess the CB1 receptors, neuronal nuclear protein, microglia (Iba1), and astrocytes (GFAP). Results showed that cocaine administration increased [18F]FDG uptake following sensitization. CBD treatment also increased [18F]FDG uptake in both saline and cocaine groups. However, animals that were sensitized and challenged with cocaine, and those receiving only an acute cocaine injection during the challenge phase, did not exhibit increased [18F]FDG uptake when treated with CBD. Furthermore, CBD induced modifications in the integrated density of NeuN, Iba, GFAP, and CB1R in the hippocampus and amygdala. This is the first study addressing the impact of CBD on brain glucose metabolism in a preclinical model of CUD using PET. Our findings suggest that CBD disrupts cocaine-induced changes in brain energy consumption and activity, which might be correlated with alterations in neuronal and glial function.

Drugs of abuse hijack a mesolimbic pathway that processes homeostatic need.

Drugs of abuse are thought to promote addiction in part by "hijacking" brain reward systems, but the underlying mechanisms remain undefined. Using whole-brain FOS mapping and in vivo single-neuron calcium imaging, we found that drugs of abuse augment dopaminoceptive ensemble activity in the nucleus accumbens (NAc) and disorganize overlapping ensemble responses to natural rewards in a cell type-specific manner. Combining FOS-Seq, CRISPR-perturbation, and single-nucleus RNA sequencing, we identified Rheb as a molecular substrate that regulates cell type-specific signal transduction in NAc while enabling drugs to suppress natural reward consumption. Mapping NAc-projecting regions activated by drugs of abuse revealed input-specific effects on natural reward consumption. These findings characterize the dynamic, molecular and circuit basis of a common reward pathway, wherein drugs of abuse interfere with the fulfillment of innate needs.

Development of an innovative analytical method for forensic detection of cocaine, antidepressants, and metabolites in postmortem blood using magnetic nanoparticles.

Cocaine and antidepressants rank high globally in substance consumption, emphasizing their impact on public health. The determination of these compounds and related substances in biological samples is crucial for forensic toxicology. This study focused on developing an innovative analytical method for the determination of cocaine, antidepressants, and their related metabolites in postmortem blood samples, using unmodified commercial Fe3O4 nanoparticles as a sorbent for dispersive magnetic solid-phase extraction (m-d-SPE), coupled with liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis. An aliquot of 100 µL of whole blood and 5 µL of the internal standard pool were added to 30 mg of nanoparticles. The nanoparticles were separated from the sample using a neodymium magnet inserted into a 3D-printed microtube rack. The liquid was then discarded, followed by desorption with 300 µL of 1/1/1 acetonitrile/methanol/ethyl acetate. The sample was vortexed and separated, and 1.5 µL of the organic supernatant was injected into the LC-MS/MS. The method was acceptably validated and successfully applied to 263 postmortem blood samples. All samples evaluated in this study were positive for at least one substance. The most frequent analyte was benzoylecgonine, followed by cocaine and cocaethylene. The most common antidepressants encountered in the analyzed samples were citalopram and fluoxetine, followed by fluoxetine's metabolite norfluoxetine. This study describes the first report of this sorbent in postmortem blood analysis, demonstrating satisfactory results for linearity, precision, accuracy, and selectivity for all compounds. The method's applicability was confirmed, establishing it as an efficient and sustainable alternative to traditional techniques for forensic casework.

Decoding cocaine-induced proteomic adaptations in the mouse nucleus accumbens.

Cocaine use disorder (CUD) is a chronic neuropsychiatric condition that results from enduring cellular and molecular adaptations. Among substance use disorders, CUD is notable for its rising prevalence and the lack of approved pharmacotherapies. The nucleus accumbens (NAc), a region that is integral to the brain's reward circuitry, plays a crucial role in the initiation and continuation of maladaptive behaviors that are intrinsic to CUD. Leveraging advancements in neuroproteomics, we undertook a proteomic analysis that spanned membrane, cytosolic, nuclear, and chromatin compartments of the NAc in a mouse model. The results unveiled immediate and sustained proteomic modifications after cocaine exposure and during prolonged withdrawal. We identified congruent protein regulatory patterns during initial cocaine exposure and reexposure after withdrawal, which contrasted with distinct patterns during withdrawal. Pronounced proteomic shifts within the membrane compartment indicated adaptive and long-lasting molecular responses prompted by cocaine withdrawal. In addition, we identified potential protein translocation events between soluble-nuclear and chromatin-bound compartments, thus providing insight into intracellular protein dynamics after cocaine exposure. Together, our findings illuminate the intricate proteomic landscape that is altered in the NAc by cocaine use and provide a dataset for future research toward potential therapeutics.

Point-of-care testing of methamphetamine and cocaine utilizing wearable sensors.

The imperative for the point-of-care testing of methamphetamine and cocaine in drug abuse prevention necessitates innovative solutions. To address this need, we have introduced a multi-channel wearable sensor harnessing CRISPR/Cas12a system. A CRISPR/Cas12a based system, integrated with aptamers specific to methamphetamine and cocaine, has been engineered. These aptamers function as signal-mediated intermediaries, converting methamphetamine and cocaine into nucleic acid signals, subsequently generating single-stranded DNA to activate the Cas12 protein. Additionally, we have integrated a microfluidic system and magnetic separation technology into the CRISPR system, enabling rapid and precise detection of cocaine and methamphetamine. The proposed sensing platform demonstrated exceptional sensitivity, achieving a detection limit as low as 0.1 ng/mL. This sensor is expected to be used for on-site drug detection in the future.

Accidental substance-related acute toxicity deaths among youth in Canada: a descriptive analysis of a national chart review study of coroner and medical examiner data. / Décès accidentels attribuables à une intoxication aiguë due à une substance chez les jeunes au Canada : analyse descriptive d'une étude nationale portant sur l'examen des dossiers des données de coroners et de médecins légistes.

INTRODUCTION: Substance-related acute toxicity deaths (ATDs) are a public health crisis in Canada. Youth are often at higher risk for substance use due to social, environmental and structural factors. The objectives of this study were to understand the characteristics of youth (aged 12-24 years) dying of accidental acute toxicity in Canada and examine the substances contributing to and circumstances surrounding youth ATDs. METHODS: Data from a national chart review study of coroner and medical examiner data on ATDs that occurred in Canada between 2016 and 2017 were used to conduct descriptive analyses with proportions, mortality rates and proportionate mortality rates. Where possible, youth in the chart review study were compared with youth in the general population and youth who died of all causes, using census data. RESULTS: Of the 732 youth who died of accidental acute toxicity in 2016-2017, most (94%) were aged 18 to 24 years. Youth aged 20 to 24 who were unemployed, unhoused or living in collective housing were overrepresented among accidental ATDs. Many of the youth aged 12 to 24 who died of accidental acute toxicity had a documented history of substance use. Fentanyl, cocaine and methamphetamine were the most common substances contributing to death, and 38% of the deaths were witnessed or potentially witnessed. CONCLUSION: The findings of this study point to the need for early prevention and harm reduction strategies and programs that address mental health, exposure to trauma, unemployment and housing instability to reduce the harms of substance use on Canadian youth.

Accidental substance-related acute toxicity deaths in older adults in 2016 and 2017: a national chart review study. / Décès accidentels liés à une intoxication aiguë due à une substance chez les aînés en 2016 et en 2017 : une étude nationale d'examen des dossiers.

INTRODUCTION: Limited research exists on substance-related acute toxicity deaths (ATDs) in older adults (≥60 years) in Canada. This study aims to examine and describe the sociodemographic characteristics, health histories and circumstances of death for accidental ATDs among older adults. METHODS: Following a retrospective descriptive analysis of all coroner and medical examiner files on accidental substance-related ATDs in older adults in Canada from 2016 to 2017, proportions and mortality rates for coroner and medical examiner data were compared with general population data on older adults from the 2016 Census. Chisquare tests were conducted for categorical variables where possible. RESULTS: From 2016 to 2017, there were 705 documented accidental ATDs in older adults. Multiple substances contributed to 61% of these deaths. Fentanyl, cocaine and ethanol (alcohol) were the most common substances contributing to death. Heart disease (33%), chronic pain (27%) and depression (26%) were commonly documented. Approximately 84% of older adults had contact with health care services in the year preceding their death. Only 14% were confirmed as having their deaths witnessed. CONCLUSIONS: Findings provide insight into the demographic, contextual and medical history factors that may influence substance-related ATDs in older adults and suggest key areas for prevention.

Isradipine, an L-type calcium channel blocker, attenuates cocaine effects in mice by reducing central glutamate release.

Substance abuse disorder is a chronic condition for which pharmacological treatment options remain limited. L-type calcium channels (LTCC) have been implicated in drug-related plasticity and behavior. Specifically, dopaminergic neurons in the mesocorticolimbic pathway express Cav1.2 and Cav1.3 channels, which may regulate dopaminergic activity associated with reward behavior. Therefore, this study aimed to investigate the hypothesis that pre-administration of the LTCC blocker, isradipine can mitigate the effects of cocaine by modulating central glutamatergic transmission. For that, we administered isradipine at varying concentrations (1, 7.5, and 15 µg/µL) via intracerebroventricular injection in male Swiss mice. This pretreatment was carried out prior to subjecting animals to behavioral assessments to evaluate cocaine-induced locomotor sensitization and conditioned place preference (CPP). The results revealed that isradipine administered at a concentration of 1 µg/µL effectively attenuated both the sensitization and CPP induced by cocaine (15 mg/kg, via i. p.). Moreover, mice treated with 1 µg/µL of isradipine showed decreased presynaptic levels of glutamate and calcium in the cortex and hippocampus as compared to control mice following cocaine exposure. Notably, the gene expression of ionotropic glutamate receptors, AMPA, and NMDA, remained unchanged, as did the expression of Cav1.2 and Cav1.3 channels. Importantly, these findings suggest that LTCC blockage may inhibit behavioral responses to cocaine, most likely by decreasing glutamatergic input in areas related to addiction.