Approximately 50 million Americans suffer from chronic pain, and nearly a quarter of chronic pain patients have reported misusing opioid prescriptions. Repeated drug seeking is associated with reactivation of an ensemble of neurons sparsely scattered throughout the dorsomedial prefrontal cortex (dmPFC). Prior research has demonstrated that chronic pain increases intrinsic excitability of dmPFC neurons, which may increase the likelihood of reactivation during drug seeking. We tested the hypothesis that chronic pain would increase oxycodone-seeking behaviour and that the pain state would differentially increase intrinsic excitability in dmPFC drug-seeking ensemble neurons. TetTag mice self-administered intravenous oxycodone. After 7 days of forced abstinence, a drug-seeking session was performed, and the ensemble was tagged. Mice received spared nerve injury (SNI) to induce chronic pain during the period between the first and second seeking session. Following the second seeking session, we performed electrophysiology on individual neurons within the dmPFC to assess intrinsic excitability of the drug-seeking ensemble and non-ensemble neurons. SNI had no impact on sucrose seeking or intrinsic excitability of dmPFC neurons from these mice. In females, SNI increased oxycodone seeking and intrinsic excitability of non-ensemble neurons. In males, SNI had no impact on oxycodone seeking or neuron excitability. Data from females are consistent with clinical reports that chronic pain can promote drug craving and relapse and support the hypothesis that chronic pain itself may lead to neuroadaptations which promote opioid seeking.

The influences of Oxycodone (OXY) combined with Paclitaxel (PTX) on breast cancer cells are unclear. The present study aimed to examine the effects of OXY combined with PTX on the proliferation, apoptosis, and migration of human breast cancer SKBR3 cells and the underlying mechanism.
The proliferation, apoptosis and invasion of SKBR3 cells were assessed by CCK-8, colony formation assay, flowcytometric, Transwell assay and scratch assays, respectively. In addition, Western blotting was used to detect the expression of related proteins in these cells. The autophagic bodies were observed under a transmission electron microscope.
OXY (0.25, 0.5 and 1 mM) significantly inhibited the viability, colony-forming, migration, and invasion of SKBR3 cells as compared to the control group. Furthermore, OXY (0.25, 0.5 and 1 mM) markedly induced the apoptosis of SKBR3 cells and the levels of apoptosis-related proteins. In addition, OXY (0.25, 0.5 and 1 mM) and PTX inhibited the proliferation of SKBR3 cells synergistically as compared to PTX group in vitro. Moreover, OXY (0.25, 0.5 and 1 mM) significantly elevated the PTX-induced apoptosis in SKBR3 cells via downregulating the expression of N-cadherin, Becline-1 LC3-Ⅱ, p-Akt and p-mTOR and upregulating E-cadherin expression. Compared with the control group, OXY (1 mM) treatment induced autophagy in SKBR3 cells.
The present study indicates that OXY can enhance the antitumor effect of PTX on breast cancer in vitro. Hence, the combination of OXY with PTX may serve as a potential strategy for the treatment of breast cancer.

Myocardial injury and cardiovascular dysfunction are the most common complications of sepsis, and effective therapeutic candidate is still lacking. This study aims to investigate the protective effect of oxycodone in myocardial injury of lipopolysaccharide-induced sepsis and its related signalling pathways. Wild-type and nuclear factor erythroid 2-related factor 2 (Nrf2)-knockout mice, as well as H9c2 cardiomyocytes cultures treated with lipopolysaccharide (LPS) were used as models of septic myocardial injury. H9c2 cardiomyocytes culture showed that oxycodone protected cells from pyroptosis induced by LPS. Mice model confirmed that oxycodone pretreatment significantly attenuated myocardial pathological damage and improved cardiac function demonstrated by increased ejection fraction (EF) and fractional shortening (FS), as well as decreased cardiac troponin I (cTnI) and creatine kinase isoenzymes MB (CK-MB). Oxycodone also reduced the levels of inflammatory factors and oxidative stress damage induced by LPS, which involves pyroptosis-related proteins including: Nod-like receptor protein 3 (NLRP3), Caspase 1, Apoptosis-associated speck-like protein contain a CARD (ASC), and Gasdermin D (GSDMD). These changes were mediated by Nrf2 and heme oxygenase-1 (HO-1) because Nrf2-knockout mice or Nrf2 knockdown in H9c2 cells significantly reversed the beneficial effect of oxycodone on oxidative stress, inflammatory responses and NLRP3-mediated pyroptosis. Our findings yielded that oxycodone therapy reduces LPS-induced myocardial injury by suppressing NLRP3-mediated pyroptosis via the Nrf2/HO-1 signalling pathway in vivo and in vitro.

Over the past decades, extensive preclinical research has been conducted to develop vaccinations to protect against substance use disorder caused by opioids, nicotine, cocaine, and designer drugs. Morphine or fentanyl derivatives are small molecules, and these compounds are not immunogenic, but when conjugated as haptens to a carrier protein will elicit the production of antibodies capable of reacting specifically with the unconjugated hapten or its parent compound. The position of the attachment in opioid haptens to the carrier protein will influence the specificity of the antiserum produced in immunized animals with the hapten-carrier conjugate. Immunoassays for the determination of opioid drugs are based on the ability of drugs to inhibit the reaction between drug-specific antibodies and the corresponding drug-carrier conjugate or the corresponding labelled hapten. Pharmacological studies of the hapten-carrier conjugates resulted in the development of vaccines for treating opioid use disorders (OUDs). Immunotherapy for opioid addiction includes the induction of anti-drug vaccines which are composed of a hapten, a carrier protein, and adjuvants. In this review we survey the design of opioid haptens, the development of the opioid radioimmunoassay, and the results of immunotherapy for OUDs.

Oxycodone, often used as an analgesic, is a potent opioid. While its effectiveness has been proven in the control of moderate to acute pain, excessive use of oxycodone imposes heart failure, heart palpitations, reduction of red blood cells, bone pain, and even death. Therefore, monitoring the oxycodone concentration in blood is vital for emergency care. For this purpose, a novel electrochemical sensor was designed based on a glassy carbon electrode modified with mesoporous g-C3N4 (M-C3N4), carbon nano-onions doped with nitrogen (N-CNO), and gold nanoparticles. At first, the SEM and XRD techniques were employed to characterize prepared M-C3N4 and N-CNO samples. The electro-oxidation behavior of the oxycodone was evaluated by cyclic and differential pulse voltammetric methods. Based on the influence of the potential scanning rate and solution pH on the voltammetric response of oxycodone oxidation, a redox mechanism was proposed. A 16 nM detection limit was acquired for the oxycodone analysis with a linear response in the 0.05-150 µM range. This sensor showed a remarkable ability for oxycodone detection in plasma samples. The long-term stability, superior selectivity, and reproducibility of this sensor prove its ability to measure oxycodone accurately and precisely in authentic spices.

Availability of counterfeit prescription pills (counterfeit pills) containing illegally made fentanyl, including counterfeit M-30 oxycodone (counterfeit M-30) pills, has risen sharply in the United States and has been increasingly linked to overdose deaths. In 2023, approximately 115 million counterfeit pills were seized in U.S. High Intensity Drug Trafficking Areas. However, clinical data on counterfeit pill-related overdoses are limited. Medical toxicology consultations during 2017-2022 from one U.S. Census Bureau Western Region hospital participating in the Toxicology Investigators Consortium Core Registry were analyzed. A total of 352 cases suspected to involve counterfeit M-30 pills, including 143 (40.6%) cases of fentanyl exposure and 209 (59.4%) cases of acute withdrawal were identified; consultations increased from three in 2017, to 209 in 2022. Patients aged 15-34 years accounted for 95 (67.4%) exposure cases. Among all patients with exposures, 81.1% were hospitalized, 69.0% of whom were admitted to an intensive care unit. Additional substances were detected in 131 (91.6%) exposures. Providing outreach to younger persons misusing prescription pills, improving access to and distribution of harm reduction tools including fentanyl test strips and naloxone, and promoting linkage of persons treated for overdose in hospitals to harm reduction and substance use treatment services are strategies to reduce morbidity associated with use of counterfeit M-30.

N6-methyladenosine (m6A) methylation is a vital epigenetic mechanism associated with drug addiction. However, the relationship between m6A modification and oxycodone rewarding is less well explored. Based on an open field test, the present study evaluated oxycodone rewarding using chromatin immunoprecipitation PCR, immunofluorescence, and RNA sequencing. A marked increase in METTL14 protein and a decrease in PP1α protein due to oxycodone abundance in the striatal neurons were observed in a dose- and time-dependent manner. Oxycodone markedly increased LSD1 expression, and decreased H3K4me1 expression in the striatum. In the open field test, intra-striatal injection of METTL14 siRNA, HOTAIR siRNA, or LSD1 shRNA blocked oxycodone-induced increase in locomotor activity. The downregulation of PP1α was also inhibited after treatment with METTL14/HOTAIR siRNA and LSD1 shRNA. Enhanced binding of LSD1 with CoRest and of CoRest with the PP1α gene induced by oxycodone was also reversed by LSD1 shRNA. In addition, H3K4me1 demethylation was also blocked by the treatment. In summary, the investigation confirmed that METTL14-mediated upregulation of HOTAIR resulted in the repression of PP1α, which in turn facilitated the recruitment of LSD1, thus catalyzing H3K4me1 demethylation and promoting oxycodone addiction.

UNASSIGNED: Postoperative pain (POP) is one of the most common and most important types of pain.
UNASSIGNED: The aim of this study was to compare the effects of pre-emptive oxycodone, diclofenac, and gabapentin on postoperative pain (POP) among patients with tibia fracture surgery.
UNASSIGNED: This double-blind three-group randomised controlled trial was conducted in 2023. Participants were 111 candidates for tibia fracture surgery under general anaesthesia. They were randomly allocated to oxycodone, gabapentin, and diclofenac groups through block randomisation. Baseline arterial oxygen saturation, heart rate, and blood pressure were documented before surgery and POP and sedation status were measured during postoperative recovery and 2, 4, 6, 12, and 24 h after surgery. Postoperative opioid analgesic use was also documented. The data were analysed using the SPSS software (v. 20.0) at a significance level of less than 0.05.
UNASSIGNED: Groups did not significantly differ from each other respecting participants\' baseline age, gender, body mass index, arterial oxygen saturation, heart rate, blood pressure, and surgery duration (P > 0.05). Moreover, there were no significant differences among the groups respecting POP and sedation status at different measurement time points (P > 0.05), except for six hours after surgery at which the POP mean score in the gabapentin group was significantly less than the other two groups (P = 0.001). Among-group differences respecting postoperative use of opioid analgesics and medication side effects were also insignificant (P > 0.05).
UNASSIGNED: Pre-emptive oxycodone, diclofenac, and gabapentin significantly reduce POP among patients with tibia fracture surgery, though gabapentin may produce more significant analgesic effects. All these three medications can be used for pre-emptive analgesia. Of course, the best pre-emptive analgesic agent is determined based on the opinion of the treating physician.

Nonmedical use of prescription opioids peaks during late adolescence, a developmental period associated with the maturation of higher-order cognitive processes. To date, however, how chronic adolescent oxycodone (OXY) self-administration alters neurobehavioral (i.e., locomotion, startle reactivity) and/or neurocognitive (i.e., preattentive processes, intrasession habituation, stimulus-reinforcement learning, sustained attention) function has not yet been systematically evaluated. Hence, the rationale was built for establishing the dose-dependency of adolescent OXY self-administration on the trajectory of neurobehavioral and neurocognitive development. From postnatal day (PD) 35 to PD 105, an age in rats that corresponds to the adolescent and young adult period in humans, male and female F344/N rats received access to either oral OXY (0, 2, 5, or 10 mg/kg) or water under a two-bottle choice experimental paradigm. Independent of biological sex or dose, rodents voluntarily escalated their OXY intake across ten weeks. A longitudinal experimental design revealed prominent OXY-induced impairments in neurobehavioral development, characterized by dose-dependent increases in locomotion and sex-dependent increases in startle reactivity. Systematic manipulation of the interstimulus interval in prepulse inhibition supports an OXY-induced impairment in preattentive processes. Despite the long-term cessation of OXY intake, rodents with a history of chronic adolescent oral OXY self-administration exhibited deficits in sustained attention; albeit no alterations in stimulus-reinforcement learning were observed. Taken together, adolescent oral OXY self-administration induces selective long-term alterations in neurobehavioral and neurocognitive development enjoining the implementation of safer prescribing guidelines for this population.

Translational studies benefit from experimental designs where laboratory organisms use human-relevant behaviors. One such behavior is decision-making, however studying complex decision-making in rodents is labor-intensive and typically restricted to two levels of cost/reward. We design a fully automated, inexpensive, high-throughput framework to study decision-making across multiple levels of rewards and costs: the REward-COst in Rodent Decision-making (RECORD) system. RECORD integrates three components: 1) 3D-printed arenas, 2) custom electronic hardware, and 3) software. We validated four behavioral protocols without employing any food or water restriction, highlighting the versatility of our system. RECORD data exposes heterogeneity in decision-making both within and across individuals that is quantifiably constrained. Using oxycodone self-administration and alcohol-consumption as test cases, we reveal how analytic approaches that incorporate behavioral heterogeneity are sensitive to detecting perturbations in decision-making. RECORD is a powerful approach to studying decision-making in rodents, with features that facilitate translational studies of decision-making in psychiatric disorders.