Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069241260348
Eugen V Khomula, Jon D Levine
{"title":"Morphine acts in vitro to directly prime nociceptors.","authors":"Eugen V Khomula, Jon D Levine","doi":"10.1177/17448069241260348","DOIUrl":"10.1177/17448069241260348","url":null,"abstract":"<p><p>Hyperalgesic priming is a preclinical model of the transition from acute to chronic pain characterized by a leftward shift in the dose-response curve for and marked prolongation of prostaglandin E<sub>2</sub> (PGE<sub>2</sub>)-induced mechanical hyperalgesia, in vivo. In vitro, priming in nociceptors is characterized by a leftward shift in the concentration dependence for PGE<sub>2</sub>-induced nociceptor sensitization. In the present in vitro study we tested the hypothesis that a mu-opioid receptor (MOR) agonist opioid analgesic, morphine, can produce priming by its direct action on nociceptors. We report that treatment of nociceptors with morphine, in vitro, produces a leftward shift in the concentration dependence for PGE<sub>2</sub>-induced nociceptor sensitization. Our findings support the suggestion that opioids act directly on nociceptors to induce priming.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11149440/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141199998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069241259535
Ratan K Banik, Twan Sia, Malcolm E Johns, Phu V Tran, Andrew Y Cheng, Sudarshan Setty, Donald A Simone
{"title":"Methylene blue dose-dependently induces cutaneous inflammation and heat hyperalgesia in a novel rat model.","authors":"Ratan K Banik, Twan Sia, Malcolm E Johns, Phu V Tran, Andrew Y Cheng, Sudarshan Setty, Donald A Simone","doi":"10.1177/17448069241259535","DOIUrl":"10.1177/17448069241259535","url":null,"abstract":"<p><p>Methylene blue (MB) has been shown to reduce mortality and morbidity in vasoplegic patients after cardiac surgery. Though MB is considered to be safe, extravasation of MB leading to cutaneous toxicity has been reported. In this study, we sought to characterize MB-induced cutaneous toxicity and investigate the underlying mechanisms. To induce MB-induced cutaneous toxicity, we injected 64 adult male Sprague-Dawley rates with 200 µL saline (vehicle) or 1%, 0.1%, or 0.01% MB in the plantar hind paws. Paw swelling, skin histologic changes, and heat and mechanical hyperalgesia were measured. Injection of 1%, but not 0.1% or 0.01% MB, produced significant paw swelling compared to saline. Injection of 1% MB produced heat hyperalgesia but not mechanical hyperalgesia. Pain behaviors were unchanged following injections of 0.1% or 0.01% MB. Global transcriptomic analysis by RNAseq identified 117 differentially expressed genes (111 upregulated, 6 downregulated). Ingenuity Pathway Analysis showed an increased quantity of leukocytes, increased lipids, and decreased apoptosis of myeloid cells and phagocytes with activation of IL-1β and Fos as the two major regulatory hubs. qPCR showed a 16-fold increase in IL-6 mRNA. Thus, using a novel rat model of MB-induced cutaneous toxicity, we show that infiltration of 1% MB into cutaneous tissue causes a dose-dependent pro-inflammatory response, highlighting potential roles of IL-6, IL-1β, and Fos. Thus, anesthesiologists should administer dilute MB intravenously through peripheral venous catheters. Higher concentrations of MB (1%) should be administered through a central venous catheter to minimize the risk of cutaneous toxicity.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11162129/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141076271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069241258110
Yujie Ma, Jinjin Wan, Shun Hao, Qi-Yu Chen, Min Zhuo
{"title":"Recruitment of cortical silent responses by forskolin in the anterior cingulate cortex of adult mice.","authors":"Yujie Ma, Jinjin Wan, Shun Hao, Qi-Yu Chen, Min Zhuo","doi":"10.1177/17448069241258110","DOIUrl":"10.1177/17448069241258110","url":null,"abstract":"<p><p>Recent studies using different experimental approaches demonstrate that silent synapses may exist in the adult cortex including the sensory cortex and anterior cingulate cortex (ACC). The postsynaptic form of long-term potentiation (LTP) in the ACC recruits some of these silent synapses and the activity of calcium-stimulated adenylyl cyclases (ACs) is required for such recruitment. It is unknown if the chemical activation of ACs may recruit silent synapses. In this study, we found that activation of ACs contributed to synaptic potentiation in the ACC of adult mice. Forskolin, a selective activator of ACs, recruited silent responses in the ACC of adult mice. The recruitment was long-lasting. Interestingly, the effect of forskolin was not universal, some silent synapses did not undergo potentiation or recruitment. These findings suggest that these adult cortical synapses are not homogenous. The application of a selective calcium-permeable AMPA receptor inhibitor 1-naphthyl acetyl spermine (NASPM) reversed the potentiation and the recruitment of silent responses, indicating that the AMPA receptor is required. Our results strongly suggest that the AC-dependent postsynaptic AMPA receptor contributes to the recruitment of silent responses at cortical LTP.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11119478/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140922882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069241254455
Paul G Green, Jon D Levine
{"title":"A novel anti-pruritic: Topical co-administration of high molecular weight hyaluronan (HMWH) with protamine, a transdermal transport enhancer.","authors":"Paul G Green, Jon D Levine","doi":"10.1177/17448069241254455","DOIUrl":"10.1177/17448069241254455","url":null,"abstract":"<p><p>Pruritis, the sensation of itch, is produced by multiple substances, exogenous and endogenous, that sensitizes specialized sensory neurons (pruriceptors and pruri-nociceptors). Unfortunately, many patients with acute and chronic pruritis obtain only partial relief when treated with currently available treatment modalities. We recently demonstrated that the topical application of high molecular weight hyaluronan (HMWH), when combined with vehicles containing transdermal transport enhancers, produce potent long-lasting reversal of nociceptor sensitization associated with inflammatory and neuropathic pain. In the present experiments we tested the hypothesis that the topical formulation of HMWH with protamine, a transdermal transport enhancer, can also attenuate pruritis. We report that this topical formulation of HMWH markedly attenuates scratching behavior at the nape of the neck induced by serotonin (5-hydroxytryptamine, 5-HT), in male and female rats. Our results support the hypothesis that topical HMWH in a transdermal transport enhancer vehicle is a strong anti-pruritic.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11088296/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140899140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Role of ERK in gender difference of fibromyalgia pain.","authors":"Ju-Hsin Chang, Ke-Wei Chen, Shih-Ying Tsai, Yen-Jing Zeng, Chi-Yuan Li, Kuen-Bao Chen, Yeong-Ray Wen","doi":"10.1177/17448069241261940","DOIUrl":"10.1177/17448069241261940","url":null,"abstract":"<p><p>This study investigated the ERK pathway of the peripheral nervous system and discovered a gender-specific pattern of ERK activation in the dorsal root ganglion of an acid-induced chronic widespread muscular pain model. We employed a twice acid-induced chronic musculoskeletal pain model in rats to evaluate mechanical pain behavior in both male and female groups. We further conducted protein analysis of dissected dorsal root ganglions from both genders. Both male and female rats exhibited a similar pain behavior trend, with females demonstrating a lower pain threshold. Protein analysis of the dorsal root ganglion (DRG) showed a significant increase in phosphorylated ERK after the second acid injection in all groups. However, phosphorylation of ERK was observed in the dorsal root ganglion, with higher levels in the male ipsilateral group compared to the female group. Moreover, there was a no difference between the left and right sides in males, whereas the significant difference was observed in females. In conclusions, the administration of acid injections induced painful behavior in rats, and concurrent with this, a significant upregulation of pERK was observed in the dorsal root ganglia, with a greater magnitude of increase in males than females, and in the contralateral side compared to the ipsilateral side. Our findings shed light on the peripheral mechanisms underlying chronic pain disorders and offer potential avenues for therapeutic intervention.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11168046/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141179636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069241290114
Hejia Ge, Hongmei Zhou, Liuyi Song, Yuqing Tao, Li Hu
{"title":"Mitochondrial dysfunction and disulfidptosis co-regulate neuronal cell in neuropathic pain based on bioinformatics analysis.","authors":"Hejia Ge, Hongmei Zhou, Liuyi Song, Yuqing Tao, Li Hu","doi":"10.1177/17448069241290114","DOIUrl":"10.1177/17448069241290114","url":null,"abstract":"<p><p>Neuropathic pain (NP) affects approximately 6.9-10% of the world's population and necessitates the development of novel treatments. Mitochondria are essential in the regulation of cell death. Neuroimmune mechanisms are implicated in various forms of cell death associated with NP. However, the specific involvement of mitochondrial dysfunction and disulfidptosis in NP remains uncertain. Further research is required to gain a better understanding of their combined contribution. Our comprehensive study employs a variety of bioinformatic analysis methods, including differential gene analysis, weighted gene co-expression network analysis, machine learning, functional enrichment analysis, immune infiltration, sub-cluster analysis, single-cell dimensionality reduction and cell-cell communication to gain insight into the molecular mechanisms behind these processes. Our study rationally defines a list of key gene sets for mitochondrial dysfunction and disulfidptosis. 6 hub mitochondrial genes and 3 disulfidptosis-related genes (DRGs) were found to be associated with NP. The key genes were predominantly expressed in neurons and were lowly expressed in the NP group compared to SHAM. In addition, our macrophages used the APP (Amyloid precursor protein)-CD74 (MHC class II invariant chain) pathway to interact with neurons. These results suggest that NP is interconnected with the mechanistic processes of mitochondrial dysfunction and disulfidptosis, which may contribute to clinically targeted therapies.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11468000/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142350551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069231225845
Hasan Golmakani, Amir Azimian, Ebrahim Golmakani
{"title":"Newly discovered functions of miRNAs in neuropathic pain: Transitioning from recent discoveries to innovative underlying mechanisms.","authors":"Hasan Golmakani, Amir Azimian, Ebrahim Golmakani","doi":"10.1177/17448069231225845","DOIUrl":"10.1177/17448069231225845","url":null,"abstract":"<p><p>Neuropathic pain is a widespread clinical issue caused by somatosensory nervous system damage, affecting numerous individuals. It poses considerable economic and public health challenges, and managing it can be challenging due to unclear underlying mechanisms. Nevertheless, emerging evidence suggests that neurogenic inflammation and neuroinflammation play a role in developing pain patterns. Emerging evidence suggests that neurogenic inflammation and neuroinflammation play significant roles in developing neuropathic pain within the nervous system. Increased/decreased miRNA expression patterns could affect the progression of neuropathic and inflammatory pain by controlling nerve regeneration, neuroinflammation, and the expression of abnormal ion channels. However, our limited knowledge of miRNA targets hinders a complete grasp of miRNA's functions. Meanwhile, exploring exosomal miRNA, a recently uncovered role, has significantly advanced our comprehension of neuropathic pain's pathophysiology in recent times. In this review, we present a comprehensive overview of the latest miRNA studies and explore the possible ways miRNAs might play a role in the development of neuropathic pain.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10851769/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139040276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069241274679
Weifang Chai, Weihao Chai, Fei Guo
{"title":"Causal associations of immune cell phenotypes with migraine: A mendelian randomization study.","authors":"Weifang Chai, Weihao Chai, Fei Guo","doi":"10.1177/17448069241274679","DOIUrl":"10.1177/17448069241274679","url":null,"abstract":"<p><p>The interaction between the immune system and the brain, crucial for blood-brain barrier integrity, is a potential factor in migraine development. Although there's evidence of a connection between immune dysregulation and migraine, a clear causal link has been lacking. To bridge this knowledge gap, we performed a two-sample Mendelian randomization (MR) analysis of 731 immune cell phenotypes to determine their causality with migraine, of which parameters included fluorescence, cell abundance, count, and morphology. Sensitivity and pleiotropy checks validated our findings. After applying a false discovery rate correction, our MR study identified 35 of 731 immune phenotypes with a significant causal link to migraine (<i>p</i> < 0.05). Of these, 24 showed a protective effect (inverse variance weighting : <i>p</i> < 0.05, odds ratio <1), and 11 were risk factors (inverse variance weighting : <i>p</i> < 0.05, odds ratio >1). Although limited by population sample size and potential population-specific genetic variations, our study uncovers a significant genetic link between certain immune cell markers and migraine, providing new insights into the disorder's pathophysiology. These discoveries are crucial for developing targeted biomarkers and personalized treatments. The research enhances our understanding of immune cells' role in migraine and may substantially improve patient outcomes and lessen its socio-economic impact.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11316964/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141860356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069241289962
Weiwei Chai, Mengwei Zhang, Yan He, Weihao Chai
{"title":"Characteristics of immune cells and causal relationship with chondromalacia: A two-sample, bidirectional mendelian randomization study.","authors":"Weiwei Chai, Mengwei Zhang, Yan He, Weihao Chai","doi":"10.1177/17448069241289962","DOIUrl":"10.1177/17448069241289962","url":null,"abstract":"<p><p>Chondromalacia, characterized by the softening of cartilage, is a prevalent condition affecting joint health with complex etiology. The immune system's role in its pathogenesis has been implicated but remains to be fully elucidated. To address a critical knowledge gap, we conducted a two-sample Mendelian randomization analysis of 731 immune cell phenotypes, assessing parameters like fluorescence, cell count, and morphology. After sensitivity and pleiotropy checks, and applying a false discovery rate correction, our study linked 17 phenotypes to chondromalacia (<i>p</i> < .05). Among them, seven immune cell phenotypes were found to have a protective effect against chondromalacia (IVW: <i>p</i> < .05, OR <1), while 10 were considered risk factors (IVW:<i>p</i> < .05, OR >1). Despite the constraints of sample size and possible genetic differences among populations, our research has identified a notable genetic correlation between specific immune cell indicators and chondromalacia. This breakthrough sheds light on the pathophysiological mechanisms of the condition. The identification of protective and risk-associated immune cell phenotypes provides a foundation for further exploration of immunological mechanisms in chondromalacia and may pave the way for targeted interventions. Future research is warranted to validate these findings and explore their clinical implications.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11528737/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142308165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular PainPub Date : 2024-01-01DOI: 10.1177/17448069241266683
Zhaoxiang Zhou, Qi-Yu Chen, Min Zhuo, Ping-Yi Xu
{"title":"Inhibition of calcium-stimulated adenylyl cyclase subtype 1 (AC1) for the treatment of pain and anxiety symptoms in Parkinson's disease mice model.","authors":"Zhaoxiang Zhou, Qi-Yu Chen, Min Zhuo, Ping-Yi Xu","doi":"10.1177/17448069241266683","DOIUrl":"10.1177/17448069241266683","url":null,"abstract":"<p><p>Pain and anxiety are two common and undertreated non-motor symptoms in Parkinson's disease (PD), which affect the life quality of PD patients, and the underlying mechanisms remain unclear. As an important subtype of adenylyl cyclases (ACs), adenylyl cyclase subtype 1 (AC1) is critical for the induction of cortical long-term potentiation (LTP) and injury induced synaptic potentiation in the cortical areas including anterior cingulate cortex (ACC) and insular cortex (IC). Genetic deletion of AC1 or pharmacological inhibition of AC1 improved chronic pain and anxiety in different animal models. In this study, we proved the motor deficit, pain and anxiety symptoms of PD in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice model. As a lead candidate AC1 inhibitor, oral administration (1 dose and seven doses) of NB001 (20 and 40 mg/kg) showed significant analgesic effect in MPTP-treated mice, and the anxiety behavior was also reduced (40 mg/kg). By using genetic knockout mice, we found that AC1 knockout mice showed reduced pain and anxiety symptoms after MPTP administration, but not AC8 knockout mice. In summary, genetic deletion of AC1 or pharmacological inhibition of AC1 improved pain and anxiety symptoms in PD model mice, but didn't affect motor function. These results suggest that NB001 is a potential drug for the treatment of pain and anxiety symptoms in PD patients by inhibiting AC1 target.</p>","PeriodicalId":19010,"journal":{"name":"Molecular Pain","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11282525/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141443091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}