Pain
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Case Reports Randomized Controlled Trial Comparative Study
Drug-induced liver injury following a repeated course of ketamine treatment for chronic pain in CRPS type 1 patients: a report of 3 cases.
Studies on the efficacy of ketamine in the treatment of chronic pain indicate that prolonged or repetitive infusions are required to ensure prolonged pain relief. Few studies address ketamine-induced toxicity. Here we present data on the occurrence of ketamine-induced liver injury during repeated administrations of S(+)-ketamine for treatment of chronic pain in patients with complex regional pain syndrome type 1 as part of a larger study exploring possible time frames for ketamine re-administration. ⋯ In all patients, the ketamine infusion was promptly terminated and the liver enzymes slowly returned to reference values within 2 months. Our data suggest an increased risk for development of ketamine-induced liver injury when the infusion is prolonged and/or repeated within a short time frame. Regular measurements of liver function are therefore required during such treatments.
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Randomized Controlled Trial Comparative Study
Targeting temporomandibular disorder pain treatment to hormonal fluctuations: a randomized clinical trial.
Mounting evidence supports the importance of hormonal fluctuations in temporomandibular disorder (TMD) pain among women. Stabilizing influential hormones or having a plan and skills for coping with hormonally related increases in TMD pain, therefore, may be beneficial for women with TMD pain. This randomized clinical trial evaluated the short- and long-term efficacy of 3 interventions for women with TMD pain: (1) dental hygienist-delivered pain self-management training (SMT; n=59); (2) the same dental hygienist-delivered pain self-management training, but with a focus on menstrual cycle-related changes in pain and other symptoms (targeted SMT, or TSMT; n=55); and (3) continuous oral contraceptive therapy (6-month trial) aimed at stabilizing hormones believed to be influential in TMD pain (COCT; n=57). ⋯ The benefits of the self-management interventions relative to COCT for pain and activity interference were statistically significant at 12 months, but not at 6 months, whereas the benefits for the process measures generally were apparent at both time points. COCT was associated with multiple adverse events (none serious). The study provides further support for long-term benefits of a safe, low-intensity (2 in-person sessions and 6 brief telephone contacts), dental hygienist-delivered self-management treatment for TMD pain.
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Comparative Study
Spatiotemporal and anatomical analyses of P2X receptor-mediated neuronal and glial processing of sensory signals in the rat dorsal horn.
Extracellularly released adenosine triphosphate (ATP) modulates sensory signaling in the spinal cord. We analyzed the spatiotemporal profiles of P2X receptor-mediated neuronal and glial processing of sensory signals and the distribution of P2X receptor subunits in the rat dorsal horn. Voltage imaging of spinal cord slices revealed that extracellularly applied ATP (5-500 μM), which was degraded to adenosine and acting on P1 receptors, inhibited depolarizing signals and that it also enhanced long-lasting slow depolarization, which was potentiated after ATP was washed out. ⋯ Astrocytes expressed the P2X(7) subunit. These findings indicate that extracellular ATP is degraded into adenosine and prevents overexcitation of the sensory system, and that ATP acts on pre- and partly on postsynaptic neuronal P2X receptors and enhances synaptic transmission, predominantly in the deep layer. Astrocytes are involved in sensitization of sensory network activity more importantly in the superficial than in the deep layer.
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Comparative Study
Peripheral inflammation suppresses inward rectifying potassium currents of satellite glial cells in the trigeminal ganglia.
Previous studies indicate that silencing Kir4.1, a specific inward rectifying K(+) (Kir) channel subunit, in sensory ganglionic satellite glial cells (SGCs) induces behavioral hyperalgesia. However, the function of Kir4.1 channels in SGCs in vivo under pathophysiological conditions remains to be determined. The aim of the present study was to examine whether peripheral inflammation in anesthetized rats alters the SGC Kir4.1 current using in vivo patch clamp and immunohistochemical techniques. ⋯ Mean membrane potential in inflamed rats was more depolarized than in naïve rats. These results suggest that inflammation could suppress Kir4.1 currents of SGCs in the TRGs and that this impairment of glial potassium homeostasis in the TRGs contributes to trigeminal pain. Therefore, the Kir4.1 channel in SGCs may be a new molecular target for the treatment of trigeminal inflammatory pain.