Comparison between opioid (morphine) and vehicle treatments in mouse trigeminal ganglia and nucleus accumbens
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ABSTRACT: Chronic opioid treatment elicits hyperalgesia in mice that is significantly augmented by a human migraine trigger and reduced with migraine therapy. The purpose of this study was to profile mRNA levels (transcriptome) to understand the differences between opioid (morphine) and vehicle treatments in two nervous system regions, the trigeminal ganglia and the nucleus accumbens. Mice received 10 mL/kg intraperitoneal injections of either morphine or vehicle volume twice daily (s.c.) for 4 days where on days 1-3 the dose of morphine was 20 mg/kg, and on day 4 it was 40 mg/kg.
Project description:Opioid use during pregnancy can lead to negative infant health outcomes, including neonatal opioid withdrawal syndrome (NOWS). NOWS comprises gastrointestinal, autonomic nervous system, and neurological dysfunction that manifest during spontaneous withdrawal. Current treatments involve non-pharmacological and pharmacological interventions, however, there is no one standardized approach, in part because of variability in NOWS severity. To effectively model NOWS traits in mice, we used a third trimester-approximate opioid exposure paradigm, where neonatal inbred FVB/NJ and outbred Carworth Farms White (CFW) pups were injected twice-daily with morphine (10-15 mg/kg, s.c.) or saline (0.9%, 20 ul/g, s.c.) from postnatal day (P) one to P14. We observed reduced body weight gain, hypothermia, thermal hyperalgesia, and increased ultrasonic vocalizations (USVs). Neonatal USVs are emitted exclusively in isolation to communicate distress and thus serve as a model behavior for affective states. On P14, we observed altered USV syllable profiles during spontaneous morphine withdrawal, including an increase in Complex 3 syllables in FVB/NJ females (but not males) and in CFW mice of both sexes. Brainstem transcriptomics revealed an upregulation of the kappa opioid receptor (Oprk1), whose activation has previously been shown to contribute to withdrawal-induced dysphoria. Treatment with the kappa opioid receptor (KOR) antagonist, nor-BNI (30 mg/kg, s.c.), significantly reduced USV emission in FVB/NJ females, but not FVB/NJ males during spontaneous morphine withdrawal. Furthermore, treatment with the KOR agonist, U50,488h (0.625 mg/kg, s.c.), was sufficient to increase USV emission on P10 (both sexes) and on P14 (females only) in FVB/NJ mice. Together, these results indicate a female-specific recruitment of the dynorphin/KOR system in neonatal opioid withdrawal symptom severity.
Project description:Chronic opiate use produces molecular and cellular adaptations in the nervous system, leading to tolerance, physical dependence and addiction. Genome-wide comparison of morphine-induced changes in brain transcription of mouse strains with different opioid-related phenotypes provides an opportunity to discover the relationship between gene expression and behavioral response to the drug. Experiment Overall Design: Microarray experiment was designed to determine the impact of genetic background on the transcriptional effects of morphine in the striatum. The effects of single (20 mg/kg, s.c.) and repeated morphine administration (10-40 mg/kg, 3 times daily for 5 days) were analyzed in four inbred mouse strains (129P3/J. DBA/2J, C57BL/6J, SWR/J). Twelve experimental groups were compared. Control animals received injections of saline. Three independent biological replicates of the microarray were prepared for each experimental group. For each array, independent pools of total RNA from three animals were prepared.
Project description:The Opioid Use Disorder epidemic led to an increase in cases of Nenonatal Opioid Withdrawal Syndrome (NOWS) in infants born to opioid-dependent mothers. Hallmark features include weight loss, irritability, inconsolability, insomnia, and increased pain sensitivity. The neurobiological basis of NOWS is largely unknown. Improved mouse models will facilitate mechanistic and treatment discovery. We treated neonatal outbred Cartworth Farms White (CFW) mice (Swiss Webster) with morphine sulfate (15 mg/kg, s.c.) twice daily on postnatal day (P)1 through P14, the approximate third trimester-equivalent of human gestation. Weight loss was monitored and behavioral symptoms were measured on P7 and P14 at 16 h post-morphine. Brainstem containing pons and medulla was collected on P14 and processed for transcriptome analysis via mRNA sequencing (RNA-seq). Morphine induced weight loss from P2 to P14 that remained at P21 and P50. Repeated morphine also induced a delayed self-righting latency at P4 and a persistent, female-specific delay at P14. Morphine-treated females also showed an earlier increase in ultrasonic vocalizations (USVs) on P7. Both morphine-treated sexes showed a large increase in USVs on P14. Furthermore, thermal nociception via hot plate and tail withdrawal assays indicated that mice exhibited thermal hyperalgesia on P7 and P14, with females showing greater hyperalgesia (tail withdrawal) on P7. Morphine-treated mice also exhibited anxiety-like behavior at P21 (open field). Finally, brainstem transcriptome analysis identified a canonical gene set relevant to opioid signaling in males and a distinct gene set in females that was enriched for ribosomal proteins, mitochondrial function and neurodegenerative disorders. Sex-specific transcriptomic neuroadaptations implicate sex-specific treatments.
Project description:Chronic nitroglycerin treatment elicits hyperalgesia in mice that is significantly augmented by a human migraine trigger and reduced with migraine therapy. The purpose of this study was to profile mRNA levels (transcriptome) to understand the differences between nitroglicerin and vehicle treatments in two nervous system regions, the trigeminal ganglia and the nucleus accumbens,
Project description:Prenatal opioid exposure is a major health concern in the United States, with the incidence of neonatal opioid withdrawal syndrome (NOWS) escalating in recent years. NOWS is revealed upon cessation of in utero opioid exposure and is characterized by increased irritability, disrupted sleep patterns, high-pitched crying, and erratic feeding. The main pharmacological treatment strategy for alleviating symptoms is opioid maintenance therapy. The neural mechanisms mediating NOWS and the long-term neurobehavioral effects are poorly understood. We used a third trimester-approximate model in which neonatal outbred pups (Cartworth Farms White; CFW) were administered once-daily morphine (15 mg/kg, s.c.) from postnatal day (P) day 1 through P14 and were then assessed for behavioral and transcriptomic adaptations within the nucleus accumbens (NAc) on P15. We also investigated the long-term effects of perinatal morphine exposure on adult learning and reward sensitivity. We observed significant weight deficits, spontaneous thermal hyperalgesia, and altered ultrasonic vocalization (USV) profiles following repeated morphine and during spontaneous withdrawal. Transcriptome analysis of NAc from opioid-withdrawn P15 neonates via bulk mRNA sequencing identified an enrichment profile consistent with downregulation of myelin-associated transcripts. Despite the neonatal behavioral and molecular effects, there were no significant long-term effects of perinatal morphine exposure on adult spatial memory function in the Barnes Maze, emotional learning in fear conditioning, or in baseline or methamphetamine-potentiated reward sensitivity as measured via intracranial self-stimulation. Thus, the once daily third trimester-approximate exposure regimen, while inducing NOWS model traits and significant transcriptomic effects in neonates, had no significant long-term effects on adult behaviors.
Project description:Using an oral self-administration paradigm, we have seen morphine increase neural activity in the Paraventricular Nucleus of the Thalamus (PVT). Morphine binds primarily to Mu Opioid Receptors (MORs), which are highly expressed in the PVT. Translating Ribosome Affinity Purification (TRAP)-Sequencing was conducted on PVT neurons that express MORs
Project description:Opioid analgesics are frequently prescribed in the United States and worldwide. However, serious side effects such as addiction, immunosuppression and gastrointestinal symptoms limit long term use. In the current study using a chronic morphine-murine model a longitudinal approach was undertaken to investigate the role of morphine modulation of gut microbiome as a mechanism contributing to the negative consequences associated with opioids use. The results revealed a significant shift in the gut microbiome and metabolome within 24 hours following morphine treatment when compared to placebo. Morphine induced gut microbial dysbiosis exhibited distinct characteristic signatures profiles including significant increase in communities associated with pathogenic function, decrease in communities associated with stress tolerance. Collectively, these results reveal opioids-induced distinct alteration of gut microbiome, may contribute to opioids-induced pathogenesis. Therapeutics directed at these targets may prolong the efficacy long term opioid use with fewer side effects.
Project description:Recent evidence has demonstrated that the gut microbiome has marked effects on neuronal function and behavior. Disturbances to microbial populations within the gut have been linked to myriad models of neuropsychiatric disorders. However, the role of the microbiome in substance use disorders remains understudied. Here we show that male mice with their gut microbiome depleted by nonabsorbable antibiotics (Abx) exhibit decreased formation of morphine conditioned place preference across a range of doses (2.5-15 mg/kg), have decreased locomotor sensitization to morphine, and demonstrate marked changes in gene expression within the nucleus accumbens (NAc) in response to high-dose morphine (20 mg/kg × 7 days). Replacement of short-chain fatty acid (SCFA) metabolites, which are reduced by microbiome knockdown, reversed the behavioral and transcriptional effects of microbiome depletion. This identifies SCFA as the crucial mediators of microbiome-brain communication responsible for the effects on morphine reward caused by microbiome knockdown. These studies add important new behavioral, molecular, and mechanistic insight to the role of gut-brain signaling in substance use disorders
Project description:Molecular and behavioral responses to opioids are thought to be primarily mediated by neurons, although there is accumulating evidence that other cell types play a prominent role in drug addiction. To investigate cell-type-specific opioid responses, we performed single-cell RNA sequencing of the nucleus accumbens of mice following acute morphine treatment. Differential expression analysis uncovered unique morphine-dependent transcriptional responses by oligodendrocytes and astrocytes. Further analysis using RNAseq of FACS-purified oligodendrocytes revealed a large cohort of morphine-regulated genes. Importantly, the affected genes are enriched for roles in cellular pathways intimately linked to oligodendrocyte maturation and myelination, including the unfolded protein response. Altogether, our data illuminate the morphine-dependent transcriptional response by oligodendrocytes and offer mechanistic insights into myelination defects associated with opioid abuse.