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Decreased glutamatergic synaptic strength in the periaqueductal gray contributes to maintenance of visceral pain in male rats with experimental pancreatitis.

Visceral pain originating from chronic inflammation of the pancreas is often intractable and difficult to manage clinically. However, the pathogenesis of the central nervous system underlying visceral pain is still poorly understood. The aim of the present study was to investigate the role of the midbrain ventrolateral periaqueductal gray (vlPAG) in a rat model of chronic visceral pain induced by pancreatitis. In the present study, we used a well-established rat model of chronic pancreatitis induced by tail vein injection of dibutyltin dichloride (DBTC). To assess the DBTC-induced visceral pain, we examined the abdominal withdrawal by von Frey filament test. We further studied the synaptic transmission in the vlPAG by whole-cell patch-clamp electrophysiological recordings. Rats receiving DBTC injection exhibited a significantly increased withdrawal frequency to mechanical stimulation of the abdomen compared to rats injected with vehicle. Interestingly, compared to rats injected with vehicle, we found that neurons dissected from DBTC-treated rats exhibited a significantly decreased synaptic strength, which was revealed by a diminishedα-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/ N-methyl-D-aspartic acid (AMPA/NMDA) ratio in the vlPAG. Moreover, our results further demonstrated that neurons obtained from DBTC-treated rats displayed a higher paired-pulse ratio, as well as less frequent and smaller amplitudes of miniature excitatory postsynaptic currents in the vlPAG compared to rats injected with vehicle. Furthermore, intra-vlPAG microinjection of AMPA alleviated DBTC-induced abdominal hypersensitivity. Taken together, our findings suggest that diminished glutamatergic synaptic strength via both presynaptic and postsynaptic mechanisms in the midbrain vlPAG is associated with DBTC-induced abdominal hypersensitivity. In addition, activation of AMPA receptors in the vlPAG alleviates DBTC-induced abdominal hypersensitivity.

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A Longitudinal Study of the Association of Opioid Use with Change in Pain Interference and Functional Limitations in a Nationally Representative Cohort of Adults with Osteoarthritis in the United States.

Real-world data are sparse on longitudinal associations of opioid use with pain interference with activities (PIA) and daily function with osteoarthritis (OA) in the USA.

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Gender differences in how scientists present the importance of their research: observational study.

Women remain underrepresented on faculties of medicine and the life sciences more broadly. Whether gender differences in self presentation of clinical research exist and may contribute to this gender gap has been challenging to explore empirically. The objective of this study was to analyze whether men and women differ in how positively they frame their research findings and to analyze whether the positive framing of research is associated with higher downstream citations.

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Intramuscular injection of nerve growth factor as a model of temporomandibular disorder: nature, time-course, and sex differences characterising the pain experience.

Temporomandibular disorder (TMD) is a common condition that frequently transitions to chronic symptoms. Experimental pain models that mimic the symptoms of clinical TMD may be useful in understanding the mechanisms, and sex differences, present in this disorder. Here we aimed to comprehensively characterise the nature and time-course of pain, functional impairment and hyperalgesia induced by repeated intramuscular injection of nerve growth factor (NGF) into the masseter muscle, and to investigate sex differences in the NGF-induced pain experience.

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Cell specific regulation of NaV1.7 activity and trafficking in rat nodose ganglia neurons.

The voltage-gated sodium NaV1.7 channel sets the threshold for electrogenesis. Mutations in the gene encoding human NaV1.7 () cause painful neuropathies or pain insensitivity. In dorsal root ganglion (DRG) neurons, activity and trafficking of NaV1.7 are regulated by the auxiliary collapsin response mediator protein 2 (CRMP2). Specifically, preventing addition of a small ubiquitin-like modifier (SUMO), by the E2 SUMO-conjugating enzyme Ubc9, at lysine-374 (K374) of CRMP2 reduces NaV1.7 channel trafficking and activity. We previously identified a small molecule, designated , that prevented CRMP2 SUMOylation by Ubc9 to reduce NaV1.7 surface expression and currents, leading to a reduction in spinal nociceptive transmission, and culminating in normalization of mechanical allodynia in models of neuropathic pain. In this study, we investigated whether NaV1.7 control via CRMP2-SUMOylation is conserved in nodose ganglion (NG) neurons. This study was motivated by our desire to develop as a safe, non-opioid substitute for persistent pain, which led us to wonder how would impact NaV1.7 in NG neurons, which are responsible for driving the cough reflex. We found functioning NaV1.7 channels in NG neurons; however, they were resistant to downregulation via either CRMP2 knockdown or pharmacological inhibition of CRMP2 SUMOylation by CRMP2 SUMOylation and interaction with NaV1.7 was consered in NG neurons but the endocytic machinery was deficient in the endocytic adaptor protein Numb. Overexpression of Numb rescued CRMP2-dependent regulation on NaV1.7, rendering NG neurons sensitive to Altogether, these data point at the existence of cell-specific mechanisms regulating NaV1.7 trafficking.

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A Call to Action: A Specialty-Specific Course to Support the Next Generation of Clinician Scientists in Anesthesiology.

Clinical production pressure is a significant problem for faculty of anesthesiology departments who seek to remain involved in research. Lack of protected time to dedicate to research and insufficient external funding add to this long-standing issue. Recent trends in funding to the departments of anesthesiology and their academic output validate these concerns. A 2022 study examining National Institutes of Health (NIH) grant recipients associated with anesthesiology departments across 10 years (2011-2020) outlines total awarded funds at $1,676,482,440, with most of the funds awarded to only 10 departments in the United States. Of note, the total 1-year NIH funding in 2021 for academic internal medicine departments was 3 times higher than the 10-year funding of anesthesiology departments. Additionally, American Board of Anesthesiology (ABA) diplomats represent a minority (37%) of the anesthesiology researchers obtaining grant funding, with a small number of faculty members receiving a prevalence of monies. Overall, the number of publications per academic anesthesiologist across the United States remains modest as does the impact of the scholarly work. Improving environments in which academic anesthesiologists thrive may be paramount to successful academic productivity. In fact, adding to the lack of academic time is the limited bandwidth of senior academic physicians to mentor and support aspiring physician scientists. Given then the challenges for individual departments and notable successes of specialty-specific collaborative efforts (eg Foundation for Anesthesia Education and Research [FAER]), additional pooled-resource approaches may be necessary to successfully support and develop clinician scientists. It is in this spirit that the leadership of , unified with the Association of University Anesthesiologists, aim to sponsor the Introduction to Clinical Research for Academic Anesthesiologists (ICRAA) Course. Directed toward early career academic anesthesiologists who wish to gain competency specifically in the fundamentals of clinical research and receive mentorship to develop an investigative project, the yearlong course will provide participants with the skills necessary to design research initiatives, ethically direct research teams, successfully communicate ideas with data analysts, and write and submit scientific articles. Additionally, the course, articulated in a series of interactive lectures, mentored activities, and workshops, will teach participants to review articles submitted for publication to medical journals and to critically appraise evidence in published research. It is our hope that this initiative will be of interest to junior faculty of academic anesthesiology departments nationally and internationally.

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Synergistic effects of robotic surgery and IPACK nerve block on reduction of opioid consumption in total knee arthroplasty.

There are numerous strategies to combat postoperative analgesia and expedite recovery after total knee arthroplasty (TKA). The purpose of this study was to determine opioid consumption, length of stay, and functional outcomes after robotic versus standard TKA in the setting of various regional pain modalities.

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Atypical Migraine in Clinical Practice: Are We Missing It?

In countries like India, many migraine patients presenting to primary care clinics fail to fulfill standard (ICHD 3) migraine diagnostic criteria. Since they do not present with typical ICHD 3 migraine diagnostic symptoms, it is necessary to define the criteria for atypical migraine. This would ensure that the patients receive the right treatment approach, both non-pharmacological and pharmacological. Looking for triggers, family history, activity affected and absolute normality in between attacks, past episodes of episodic syndromes, prodromal and oculonasal autonomic symptoms will help in identifying the migraine origin of these headaches.

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[Intrathecal drug delivery for chronic pain management].

Intrathecal drug delivery appeared in the early eighties and allows to administer high concentrate analgesic medications in the cerebrospinal fluid with higher efficacy and a limited incidence of systemic side effects. Opioids are still the first line treatment with high-quality evidence for chronic cancer pain, and limited evidence for chronic non-cancer pain, being often considered as a last resort therapy. Device implantation requires a strict patient's selection with a close follow-up in order to adapt therapy, refill the reservoir and detect and prevent potential severe complications.

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Postoperative pain treatment after spinal fusion surgery: a systematic review with meta-analyses and trial sequential analyses.

Patients undergoing spinal surgery are at high risk of acute and persistent postoperative pain. Therefore, adequate pain relief is crucial. This systematic review aimed to provide answers about best-proven postoperative analgesic treatment for patients undergoing lumbar 1- or 2-level fusions for degenerative spine diseases. We performed a search in PubMed, Embase, and The Cochrane Library for randomized controlled trials. The primary outcome was opioid consumption after 24 hours postoperatively. We performed meta-analyses, trial sequential analyses, and Grading of Recommendations assessment to accommodate systematic errors. Forty-four randomized controlled trials were included with 2983 participants. Five subgroups emerged: nonsteroidal anti-inflammatory drugs (NSAIDs), epidural, ketamine, local infiltration analgesia, and intrathecal morphine. The results showed a significant reduction in opioid consumption for treatment with NSAID ( < 0.0008) and epidural ( < 0.0006) (predefined minimal clinical relevance of 10 mg). Concerning secondary outcomes, significant reductions in pain scores were detected after 6 hours at rest (NSAID [ < 0.0001] and intrathecal morphine [ < 0.0001]), 6 hours during mobilization (intrathecal morphine [ = 0.003]), 24 hours at rest (epidural [ < 0.00001] and ketamine [ < 0.00001]), and 24 hours during mobilization (intrathecal morphine [ = 0.03]). The effect of wound infiltration was nonsignificant. The quality of evidence was low to very low for most trials. The results from this systematic review showed that some analgesic interventions have the capability to reduce opioid consumption compared with control groups. However, because of the high risk of bias and low evidence, it was impossible to recommend a "gold standard" for the analgesic treatment after 1- or 2-level spinal fusion surgery.

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