BACKGROUND:Persistent use of prescription opioids beyond the period of surgical recovery is a large part of a public health problem linked to the current opioid crisis in the United States. However, ...few studies have been conducted to examine whether morphine reward is influenced by acute pain and injury.
METHODS:In a mouse model of incisional injury and minor trauma, animals underwent conditioning, extinction, and drug-primed reinstatement with morphine to examine the rewarding properties of morphine in the presence of acute incisional injury and drug-induced relapse, respectively. In addition, we sought to determine whether these behaviors were influenced by kappa opioid receptor signaling and measured expression of prodynorphin messenger RNA in the nucleus accumbens and medial prefrontal cortex after conditioning and before reinstatement with morphine and incisional injury.
RESULTS:In the presence of incisional injury, we observed enhancement of morphine reward with morphine-conditioned place preference but attenuated morphine-primed reinstatement to reward. This adaptation was not present in animals conditioned 12 days after incisional injury when nociceptive sensitization had resolved; however, they showed enhancement of morphine-primed reinstatement. Prodynorphin expression was greatly enhanced in the nucleus accumbens and medial prefrontal cortex of mice with incisional injury and morphine conditioning and remained elevated up to drug-primed reinstatement. These changes were not observed in mice conditioned 12 days after incisional injury. Further, kappa opioid receptor blockade with norbinaltorphimine before reinstatement reversed the attenuation induced by injury.
CONCLUSIONS:These findings suggest enhancement of morphine reward as a result of incisional injury but paradoxically a protective adaptation with incisional injury from drug-induced relapse resulting from kappa opioid receptor activation in the reward circuitry. Remote injury conferred no such protection and appeared to enhance reinstatement.
•Opioid use disorder (OUD) is a major current cause of morbidity and mortality.•Neuroimmune and neuroinflammatory mechanisms are changed in OUD.•These mechanisms can include peripheral components ...(cytokines and leukocytes).•Glia, neurons and blood–brain barrier can also be affected by inflammation in OUD.•Longitudinal multiomic biomarker/neuroimaging studies are necessary in OUD.
Opioid use disorder (OUD) is a major current cause of morbidity and mortality. Long-term exposure to short-acting opioids (MOP-r agonists such as heroin or fentanyl) results in complex pathophysiological changes to neuroimmune and neuroinflammatory functions, affected in part by peripheral mechanisms (e.g., cytokines in blood), and by neuroendocrine systems such as the hypothalamic–pituitary–adrenal (HPA) stress axis. There are important findings from preclinical models, but their role in the trajectory and outcomes of OUD in humans is not well understood. The goal of this narrative review is to examine available data on immune and inflammatory functions in persons with OUD, and to identify major areas for future research. Peripheral blood biomarker studies revealed a pro-inflammatory state in persons with OUD in withdrawal or early abstinence, consistent with available postmortem brain studies (which show glial activation) and diffusion tensor imaging studies (indicating white matter disruptions), with gradual abstinence-associated recovery. The mechanistic roles of these neuroimmune and neuroinflammatory changes in the trajectory of OUD (including recovery and medication management) cannot be examined practically with postmortem data. Collection of longitudinal data in larger-scale human cohorts would allow examination of these mechanisms associated with OUD stage and progression. Given the heterogeneity in presentation of OUD, a precision medicine approach integrating multi-omic peripheral biomarkers and comprehensive phenotyping, including neuroimaging, can be beneficial in risk stratification, and individually optimized selection of interventions for individuals who will benefit, and assessments under refractory therapy.
Polydimethylsiloxane (PDMS)-based solid-phase micro-extraction (SPME) was used along with Raman spectroscopy (RS) to separate and enhance the detection of five anesthetic compounds (halothane, ...propofol, isoflurane, enflurane, and etomidate) from aqueous and serum phases. Raman signals in the spectral ranges 250–450 cm−1 and 950–1050 cm−1 allowed the unique characterization of all five compounds when extracted into the PDMS phase. The SPME-RS detection of clinically relevant concentrations of aqueous propofol (6.5 μM) and halothane (200 μM) is shown. We quantify the partition coefficient for aqueous halothane in PDMS as log K = 1.9 ± 0.2. Solid-phase micro-extraction of the anesthetics makes their detection possible without the strong autofluorescent interference of serum proteins. Because of low solubility and/or weak Raman scattering, we found it challenging to detect enflurane, isoflurane, and etomidate directly from the aqueous phase, but could we do so with SPME enhancement. These studies show the potential of SPME-RS as a method for the direct detection of anesthetics in blood.
Chronic administration of cocaine has been shown to attenuate the functional capacity of delta opioid receptors to inhibit adenylyl cyclase activity. Abuse and withdrawal from cocaine in humans is ...associated with increases in anxiety and depression. Since recent research supports the role of delta opioid receptors in anxiety- and depression-like behaviors in rodents, we hypothesized that functional desensitization of delta opioid receptors contributes to anxiety- and depression-like behavioral phenotypes following short-term withdrawal from chronic administration of cocaine. To test this hypothesis, delta opioid receptor signaling and behaviors were evaluated 24
h after 14
days of binge-pattern cocaine administration (15
mg/kg three times daily at 1
h intervals) in male Sprague–Dawley rats. Results showed that the inhibition of adenylyl cyclase by delta opioid receptor agonists was attenuated in the frontal cortex, nucleus accumbens and caudate putamen 24
h after cessation of cocaine administration. One day withdrawal from chronic administration of cocaine resulted in increased anxiety- and depression-like behaviors as measured by the elevated plus maze and the forced swim test respectively, and no change in locomotor activity. The anxiety- and depression-like behaviors were dose-dependently reduced by acute administration of the selective delta opioid receptor agonist, SNC80. These results demonstrate that early withdrawal from cocaine resulted in increased anxiety and depression, which accompanies the desensitization of delta opioid receptor function. Furthermore, cocaine-induced anxiety- and depression-like behaviors were reversible by the delta opioid receptor agonist SNC80.
Recent reports suggest pain from surgical injury may influence the risks associated with exposure to opioids. In mice, hind-paw incision attenuates morphine-primed reinstatement due to kappa opioid ...receptor activation by dynorphin. In this focused group of studies, we examined the hypotheses that kappa-opioid receptor activation in the nucleus accumbens mediates attenuated drug- primed reinstatement after incisional surgery, and the G-protein biased mu-opioid agonist, oliceridine, leads to less priming of the dynorphin effect in comparison to morphine. To address these hypotheses, adult C57BL/6 male mice underwent intracranial cannulation for administration of the selective kappa-opioid antagonist norBNI directly into the nucleus accumbens. After recovery, they were conditioned with morphine or oliceridine after hind-paw incisional injury, then underwent extinction followed by opioid-primed reinstatement. Intra-accumbal administration of norBNI was carried out prior to testing. The nucleus accumbens and medial prefrontal cortex were extracted and analyzed for expression of prodynorphin. We observed that animals conditioned with morphine in the setting of incisional injury demonstrated blunted responses to opioid-primed reinstatement, and that the blunted responses were reversed with intra-accumbal norBNI administration. Persistently elevated levels of prodynorphin expression in the medial prefrontal cortex and nucleus accumbens were observed in the incised morphine-treated animals. However, both behavioral and molecular changes were absent in animals with incisional injury conditioned with oliceridine. These findings suggest a role for prodynorphin expression in the nucleus accumbens with exposure to morphine after surgery that may protect individuals from relapse not shared with biased mu- opioid receptor agonists.
OBJECTIVES/GOALS: Using biomarkers to identify vulnerabilities from cocaine use disorder (CUD) is a focus of recent investigations. Current clinical efforts focus on psychiatric recovery in CUD, ...however other body systems are missed. Applying blood-based transcriptomics to investigate how clinical conditions relate to CUD can alter current treatment approaches. METHODS/STUDY POPULATION: We conducted a comprehensive longitudinal study of 12 individuals (mean 53 yrs.; M/F ratio 9: 3) with CUD abstinent from cocaine. 44 blood samples collected repeatedly every 3 months for 9 months were bulk RNA sequenced. We began with phenotype harmonization grouping individuals with the following metrics; cocaine withdrawal, cue craving, generalized craving, perceived stress, and days of abstinence. We ran differential gene and transcript expression with time across grouping of metrics using the dream software and used the multivariate test to examine their associations. We used the association of gene-transcripts to determine genetic predispositions with clinical traits using the Multi-marker Analysis of GenoMic Annotation assessing their overlap to a reference GWAS database. RESULTS/ANTICIPATED RESULTS: Individuals were grouped in 2 clusters based on scores of cue craving, generalized craving, cocaine withdrawal, and 3 clusters based on days of abstinence from cocaine use. Gene-transcript(s) associationsrevealed genetic predisposition towards certain clinical conditions and substance use traits. Cannabis use disorder showed significant enrichment between the greater vs. lesser abstinent days, and lesser vs. least abstinent days at 9 months. The “drinks per week” trait showed significant gene enrichment between greater vs. lesser abstinent days at 9 months. Coronary artery disease was also enriched with greater vs. least abstinent days at 3 months. Lastly, significant baseline differences in predisposition to small vessel ischemic stroke were seen in responders with high vs low perceived stress. DISCUSSION/SIGNIFICANCE: These results from a robust and feasible pipeline suggest genetic predisposition in CUD for other substances and cardio-neurovascular diseases. This pilot study may lead to larger studies into whole genome-based blood biomarker approaches for monitoring abstinence and other clinical co-morbidities to be addressed in cocaine addiction recovery.
Introduction
Chronic postsurgical pain (CPSP) is a global issue with high prevalence. This study compared acute pain descriptors among patients undergoing carpal tunnel release (CTR) or trigger ...finger release (TFR). We hypothesized worst pain intensity on postoperative day (POD) 10 would be best to predict the time to pain resolution.
Methods
In this secondary analysis of a negative, randomized, double-blind placebo-controlled trial, adult veterans undergoing CTR or TFR were enrolled January 2012–January 2014, with data analysis February 2020–October 2020. Participants were randomized to receive minocycline 200 mg or placebo 2 h prior to the operation, then minocycline 100 mg or placebo twice daily for 5 days. The Brief Pain Inventory, assessed daily, captured three pain scores: average and worst pain over the past 24 h, and current pain intensity. Fifteen acute pain descriptors based on the pain scores (clusters, mean, median, pain scores on POD 10, and linear slopes) were compared as predictors of time to pain resolution.
Results
Of 131 randomized participants, 114 (83 CTR, 31 TFR) were included. Average pain over the last 24 h reported on POD 10 best predicted time to pain cessation. Every one-point increase in the average pain score was associated with a 36.0% reduced rate of pain cessation (HR, 0.64, 95% CI 0.55–0.74,
p
< 0.001). Average pain on POD 10 was significantly associated with the development of CPSP at 90 days (OR 1.74, 95% CI 1.30–2.33,
p
value < 0.001). The optimal cutoff score for the high-risk group was determined as average pain on POD 10 ≥ 3.
Conclusions
This study validates prior work and demonstrates the importance of assessing pain severity on POD 10 to identify patients at high risk for CPSP who are most likely to benefit from early pain intervention. Future research in diverse surgical cohorts is needed to further validate pain assessment on POD 10 as a significant predictor of CPSP.
J. Neurochem. (2010) 115, 635-642. Repeated administration of cocaine induces heightened behavioral hyperactivity termed sensitization. Although NK-3 receptors have been shown to modulate acute ...cocaine-induced behaviors, their role in behavioral sensitization is unknown. The present study investigated whether NK-3 receptor blockade altered behavioral sensitization to cocaine. Additionally, glycogen synthase kinase-3 (GSK3) has been shown to be involved in dopamine receptor signaling and in development of sensitization; therefore regulation of GSK3 activity in the nucleus accumbens was also investigated. Administration of the NK-3 receptor antagonist SB 222200 (5 mg/kg, s.c.) prior to repeated cocaine (20 mg/kg, i.p.) prevented the development of sensitized responses after a cocaine challenge. Pre-treatment with SB 222200 before a cocaine challenge also blocked expression of sensitization. Decrease in GSK3 activity demonstrated by increased phosphorylation of GSK3α and GSK3β was detected 20 mins after an acute cocaine injection. In contrast, a cocaine challenge failed to alter phosphorylation of GSK3α and GSK3β in sensitized mice. SB 222200 prior to repeated cocaine resulted in increased phosphorylation of GSK3α and GSK3β akin to changes following acute cocaine. Collectively, these findings demonstrate the involvement of NK-3 receptors in development and expression of behavioral sensitization and in regulation of GSK3 activity in the nucleus accumbens after repeated cocaine.
Acute activation or blockade of neurokinin-3 (NK-3) receptors has been shown to alter dopamine-mediated function and behaviors, however long-term effects of NK-3 receptor blockade remain largely ...unknown. The present study investigated whether acute and repeated administration of the NK-3 receptor antagonist SB 222200 altered hyperactivity induced by cocaine, and examined its effects on dopamine D1 receptor density in the striatum. Adult male CD-1 mice received either vehicle or SB 222200 (2.5 or 5 mg/kg, s.c.) 30 min before a cocaine injection (20 mg/kg, i.p.) and behavioral responses were recorded. Mice that were administered SB 222200 had an attenuated stereotypic response to cocaine compared to vehicle treated mice. Mice were also injected once daily with either vehicle or SB 222200 (5 mg/kg, s.c.) for 5 days, and after a 7-day drug-free period they were challenged with either saline, cocaine or the dopamine D1 receptor agonist SKF 82958 (0.125 or 0.25 mg/kg, i.p.). Mice injected with SB 222200 had significantly enhanced hyperactivity when challenged with cocaine or a low dose of SKF 82958 (0.125 mg/kg, i.p.) compared to control mice. Brains of mice administered vehicle or SB 222200 for 5 days were harvested after a 7-day drug-free period for dopamine D1 receptor quantification by radioligand binding.
3H SCH 23390 homogenate binding studies showed a 19.7% increase in dopamine D1 receptor density in the striatum of SB 222200 treated mice. These data suggest that repeated blockade of NK-3 receptors enhances subsequent dopamine-mediated behaviors possibly resulting from dopamine D1 receptor up-regulation in the striatum.
Prostaglandin E 2 (PGE 2 ) couples to stimulation of adenylyl cyclase through two distinct G protein-coupled receptors designated EP2 and EP4. Although
they have similar affinities for PGE 2 , the EP ...2 and EP4 receptors have distinct structural characteristics. EP2 is a 358-amino-acid protein with short third intracellular
loop and C-terminal domains, whereas EP4 consists of 488 amino acids with a long third intracellular loop and a long cytoplasmic
tail. The ability of the HA epitope-tagged receptors to undergo PGE 2 -induced internalization was examined by enzyme-linked immunosorbent assay and immunofluorescence microscopy after expression
in human embryonic kidney 293 cells. The EP2 receptor did not internalize, whereas the EP4 receptor underwent rapid internalization.
Truncation of the EP4 receptor after amino acid 350, which removes 138 residues, abolished internalization. Truncation after
amino acid 369 markedly attenuated internalization, whereas truncation after amino acid 383 had little effect. Serine and
threonine residues in the region 350 to 383 were mutated to determine their role in internalization. The mutants S370-382A,
a full-length receptor containing six serine-to-alanine mutations in the region 370 to 382, and S354-369A, containing four
serine mutations and one threonine mutation in the region 350 to 370, both internalized to the same extent as the wild-type.
A further mutant, designated S354-382A, containing amino acid substitutions S354A, S359A, S364A, S366G, T369A, S370A, S371A,
S374A, S377A, S379A, and S382A, also internalized to the same extent as the wild-type. We conclude that the C terminus of
the EP4 receptor is involved in internalization; however, serine and threonine residues do not seem to be involved.
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