Properties of Sensory Neurons Innervating Synovial Joints

Grigg, Peter

doi:10.1159/000047885

Cited by 32 publications

(23 citation statements)

References 22 publications

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“…In articular joints, extracellular protons, local production of cytokines, and increases of neurotransmitters in SF derived from the nerve fibers may work in concert to contribute to the inflammatory response. Innervation of synovial tissue (5,9,12,26) and the direct effects of the joint's neurotransmitter content have been reported (11,12,14,15,18,23,25,37). Although acid-sensing ionic channels on nociceptors may contribute to sensory transduction (22) and inflammatory processes, our data are consistent with a role for activation of metabotropic acid-sensing receptors on synovial fibroblasts in peripheral inflammatory, ischemic, and cellular proliferative processes.…”

Section: Discussionsupporting

confidence: 87%

Proton-sensing G protein-coupled receptor mobilizes calcium in human synovial cells

Christensen¹,

Kochukov²,

McNearney³

et al. 2005

American Journal of Physiology-Cell Physiology

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-Lowered extracellular pH in a variety of tissues is associated with increased tissue destruction and initiation of inflammatory processes. Although the acid-sensing receptors described previously are ion channels, we describe a G protein-coupled proton-sensitive receptor that stimulates Ca 2ϩ release from intracellular stores in a tumor-derived synoviocyte cell line (SW982) and in primary cultures of human synovial cells from patients with inflammatory arthropathies. We established a link between proton-dependent receptor activation and intracellular Ca 2ϩ mobilization by demonstrating 1) dependence on the integrity of the intracellular Ca 2ϩ store, 2) independence from extracellular Ca 2ϩ , and 3) proton-induced production of inositol phosphate and 4) by abolishing the effect with GTPase inhibitors. We propose that this G protein-coupled acid-sensing receptor linked to intracellular Ca 2ϩ mobilization in synoviocytes can contribute to downstream inflammatory and cellular proliferative processes in synovial fibroblasts. The acid-sensing receptor has distinct characteristics as a metabotropic G protein-coupled receptor on human synoviocytes in this emerging new class of receptors. calcium imaging; synoviocytes; arthritis; acid-sensing receptor INFLAMMATORY PROCESSES are often accompanied by a decrease in extracellular pH. Protons can modulate cell signaling through acid-sensing ion channels, screening surface charge, or by protonation of residues on integral membrane proteins. Tissue acidosis is an important component of ischemic and inflammatory sequelae. Inflammatory arthropathies such as rheumatoid arthritis (RA) and septic arthritis are often characterized by acidic synovial fluids (SFs) and increased hydrogen ion levels, secondary to increased cellular proliferation, metabolic activation, and subsequent lactic acid production (6,10,20,27,31,33). The effects of lowered extracellular pH on the tissue have been associated with increased destruction and worsening of the inflammatory parameters (8,28,29). In RA, synovial fibroblasts mediate the inflammatory process by releasing a number of factors, including proteases that destroy the surrounding supporting matrix. One of these, cathepsin, requires a lowered pH for activity in the degradation of collagen (28 -30 release from intracellular stores in a tumor-derived synoviocyte cell line (SW982) and in human synovial cells cultured from patients with inflammatory arthropathies. EXPERIMENTAL PROCEDURESCell lines and cell culture. The SW982 cells derived from a human synovial sarcoma are fibroblast-like synovial cells (7) obtained through the American Type Culture Collection (Bethesda, MD). The cells were maintained in Leibovitz's L-15 medium, 10% heated fetal bovine serum (FBS), 2 mM L-glutamine, 1,000 U/ml penicillin G, and 1,000 pg/ml streptomycin. Cells were incubated in a humidified cell incubator (37°C, ambient CO 2) and used in passages 4 -21. Primary lines of surface-adherent synoviocytes were derived from the SFs from therapeutic arthrocenteses of two patie...

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Section: Discussionsupporting

confidence: 87%

Proton-sensing G protein-coupled receptor mobilizes calcium in human synovial cells

Christensen¹,

Kochukov²,

McNearney³

et al. 2005

American Journal of Physiology-Cell Physiology

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“…The effusion model, whereby sterile saline is injected directly into the knee joint capsule, 7 produces a clinically relevant magnitude of the joint effusion that may be present with traumatic injury. Effusion is thought to activate group II afferents responding to stretch or pressure, [16][17][18] which in turn may facilitate group Ib interneurons and result in quadriceps AMI. 5 The pain model involves injecting hypertonic saline into the infrapatellar fat pad to produce anteromedial knee pain similar to that described in patients with patellofemoral pain syndrome.…”

mentioning

confidence: 99%

“…19 Pain is considered to initiate AMI through activation of group III and IV afferents that act as nocioceptors to signal damage or potential damage to joint structures. [16][17][18] The firing of these afferents then may lead to facilitation of group Ib interneurons, the flexion reflex, or the gamma loop, ultimately resulting in quadriceps inhibition. 20 Thus, these models allow us to create symptoms that are associated with knee injury and have the added benefit of providing a way to examine their effects in isolation.…”

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confidence: 99%

Pain and Effusion and Quadriceps Activation and Strength

Palmieri-Smith

Villwock

Downie

et al. 2013

Journal of Athletic Training

100

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Context: Quadriceps dysfunction is a common consequence of knee joint injury and disease, yet its causes remain elusive.Objective: To determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion affect the magnitude of quadriceps dysfunction.Design: Crossover study. Setting: University research laboratory.Patients or Other Participants: Fourteen (8 men, 6 women; age ¼ 23.6 6 4.8 years, height ¼ 170.3 6 9.16 cm, mass ¼ 72.9 6 11.84 kg) healthy volunteers.Intervention(s): All participants were tested under 4 randomized conditions: normal knee, effused knee, painful knee, and effused and painful knee.Main Outcome Measure(s): Quadriceps strength (Nm/kg) and activation (central activation ratio) were assessed after each condition was induced.Results: Quadriceps strength and activation were highest under the normal knee condition and differed from the 3 experimental knee conditions (P , .05). No differences were noted among the 3 experimental knee conditions for either variable (P . .05).Conclusions: Both pain and effusion led to quadriceps dysfunction, but the interaction of the 2 stimuli did not increase the magnitude of the strength or activation deficits. Therefore, pain and effusion can be considered equally potent in eliciting quadriceps inhibition. Given that pain and effusion accompany numerous knee conditions, the prevalence of quadriceps dysfunction is likely high.Key Words: arthrogenic muscle inhibition, central activation failure, voluntary activation, muscles Key PointsKnee pain and effusion resulted in arthrogenic muscle inhibition and weakness of the quadriceps. The simultaneous presence of pain and effusion did not increase the magnitude of quadriceps dysfunction. To reduce arthrogenic muscle inhibition and improve muscle strength, clinicians should employ interventions that target removing both pain and effusion.

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“…They are located in the joint capsule, which is a type of sleeve made of a dense network of connective tissues wrapping around a joint and containing the synovial fluid. These receptors-the socalled Ruffini corpuscle-respond to the deformation of the capsule and appear to play a key role when the joint approaches the end of its useful range of movement, in which case some fibres of the capsule begin stretching [28].…”

Section: Muscles Tendons and Jointsmentioning

confidence: 99%

A Brief Overview of the Human Somatosensory System

Hayward

2018

Springer Series on Touch and Haptic Systems

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This chapter provides an overview of the human somatosensory system. It is the system that subserves our sense of touch, which is so essential to our awareness of the world and of our own bodies. Without it, we could not hold and manipulate objects dextrously and securely, let alone musical instruments, and we would not have a body that belongs to us. Tactile sensations, conscious or unconscious, arise from the contact of our skin with objects. It follows that the mechanics of the skin and of the hand its interaction with objects is the source of information that our brain uses to dextrously manipulate objects, as in music playing. This information is collected by vast array of mechanoreceptors that are sensitive to the effects of contacting objects, often with the fingers, even far away for the region of contact. This information is processed by neural circuits in numerous regions of the brain to provide us with extraordinary cognitive and manipulative functions that depend so fundamentally on somatosensation. IntroductionThe overarching purpose of the somatosensory system is to inform the brain of the mechanical state of the body that it inhabits. It shares this function with the vestibular system. But whereas the vestibular system operates in the low-dimensional space of head translations and rotations, the somatosensory system takes its input from almost the entire body. The main sources of information arise in part from the load-bearing structures represented by connective tissues such as tendons and ligaments, in part from the motion-producing tissues, the muscles, and in part from the outer layers of body, that is the skin. As a result, unlike the vestibular system, which is sensitive to the movements of a rigid body-the cranium-the somatosensory system relates to

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Properties of Sensory Neurons Innervating Synovial Joints

Cited by 32 publications

References 22 publications

Proton-sensing G protein-coupled receptor mobilizes calcium in human synovial cells

Proton-sensing G protein-coupled receptor mobilizes calcium in human synovial cells

Pain and Effusion and Quadriceps Activation and Strength

A Brief Overview of the Human Somatosensory System

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