Pain
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Psychological trauma is typically accompanied by physical pain, and posttraumatic stress disorder (PTSD) often cooccurs with chronic pain. Clinical reports suggest that pain after trauma may be part of re-experiencing symptomatology. Classical conditioning can underlie visual re-experiencing because intrusions can occur as conditioned responses (CRs) to trauma-related cues. ⋯ Our data support that spatiotemporally associating innocuous cues with pain (CS) endows these cues to elicit conditioned pain responses in the absence of noxious stimulation. In this way pain can emerge as a CR with emotional and sensory components. Classical conditioning presents a possible mechanism explaining pain intrusions and, more broadly, pain experienced without a nociceptive input.
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What are the care-seeking priorities of people living with chronic pain and carers and how can these shape interdisciplinary workforce training to improve high-value pain care? Phase 1: Australian people living with chronic pain (n = 206; 90% female) and carers (n = 10; 40% female) described their pain care priorities (eDelphi, round 1). A coding framework was inductively derived from 842 pain care priorities (9 categories, 52 priorities), including validation; communication; multidisciplinary approaches; holistic care; partnerships; practitioner knowledge; self-management; medicines; and diagnosis. Phase 2: In eDelphi round 2, panellists (n = 170; valid responses) rated the importance (1 = less important; 9 = more important) of the represented framework. ⋯ More than 74% of health professionals were fairly or extremely confident in their ability to support care priorities for 6 of 9 categories (66.7%). Phase 3: An interdisciplinary panel (n = 5) mapped an existing foundation-level workforce training program against the framework, identifying gaps and training targets. Recommendations were determined for framework adoption to genuinely shape, from a partnership perspective, Australian interdisciplinary pain training.
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The transient receptor potential ion channel TRPM3 is highly prevalent on nociceptive dorsal root ganglion (DRG) neurons, but its functions in neuronal plasticity of chronic pain remain obscure. In an animal model of nonspecific low back pain (LBP), latent spinal sensitization known as nociceptive priming is induced by nerve growth factor (NGF) injection. Here, we address the TRPM3-associated molecular basis of NGF-induced latent spinal sensitization at presynaptic level by studying TRPM3-mediated calcium transients in DRG neurons. ⋯ TRPM3 activation provokes an outbreak of pulsatile superoxide production (mitoflash) that comes in the form of a surge in frequency being tunable. We suggest that mitoflash pulsations downstream of TRPM3 activation might be an early signaling event initiating pain sensitization. Tuning of mitoflash activity would be a novel bottom-up therapeutic strategy for chronic pain conditions such as LBP and beyond.
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The transient receptor potential cation channel subfamily M member-3 (TRPM3) channel is a recently recognized noxious heat sensor that is involved in inflammatory thermal hyperalgesia. To examine its involvement in the development of hyperalgesia in interstitial cystitis/painful bladder syndrome (IC/PBS), rats with cyclophosphamide (CYP)-induced chronic cystitis were used as a model of IC/PBS. Mechanical and thermal hyperalgesia in lower abdominal region overlying the bladder in CYP rats were measured using von Frey filaments and radiant heat, respectively. ⋯ In CYP rats, pretreatment with the TRPM3 antagonist primidone (2 mg/kg, i.p.) significantly alleviated the mechanical and thermal hyperalgesia, bladder submucosal edema, mast cell infiltration, and bladder hyperactivity. Cyclophosphamide-induced cystitis was associated with TRPM3 upregulation at the mRNA, protein, and functional levels in bladder afferent neurons. Our results suggest that upregulation of TRPM3 channels is involved in the development of chronic pain in CYP-induced cystitis, and targeting TRPM3 may be a pharmacological strategy for treating bladder pain in IC/PBS.
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Low back pain (LBP) follows different pain trajectories, and patients seem to recognize their trajectory. This allows self-reported visual pain trajectories (SRVTs) to support patient-provider communication. Pain trajectories appear stable over time for many patients, but the evidence is sparse. ⋯ The preference ORs indicated that transitions occurred mainly to similar SRVTs differing in only 1 subscale. Transitions to less or more intense SRVTs were associated with changes in clinical outcomes in the expected direction. Despite distinctly different SRVTs identified, individuals reported relatively stable LBP phenotypes but with potential for change.