Pain
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The nociceptive transmission under pathological chronic pain conditions involves transcriptional and/or translational alteration in spinal neurotransmitters, receptor expressions, and modification of neuronal functions. Studies indicate the involvement of microRNA (miRNA) - mediated transcriptional deregulation in the pathophysiology of acute and chronic pain. In the present study, we tested the hypothesis that long-term cross-organ colonic hypersensitivity in neonatal zymosan-induced cystitis is due to miRNA-mediated posttranscriptional suppression of the developing spinal GABAergic system. ⋯ An increase in miR-181a concomitantly resulted in significant down-regulation of GABA(Aα-1) receptor subunit gene and protein expression in adult spinal cords from rats with neonatal cystitis. Intrathecal administration of the GABA(A) receptor agonist muscimol failed to attenuate the viscero-motor response (VMR) to colon distension in rats with neonatal cystitis, whereas in adult zymosan-treated rats the drug produced significant decrease in VMR. These results support an integral role for miRNA-mediated transcriptional deregulation of the GABAergic system in neonatal cystitis-induced chronic pelvic pain.
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Joint pain is a common clinical problem for which both inflammatory and degenerative joint diseases are major causes. The purpose of this study was to investigate the role of CB1 and CB2 cannabinoid receptors in the behavioral, histological, and neurochemical alterations associated with joint pain. The murine model of monosodium iodoacetate (MIA) was used to induce joint pain in knockout mice for CB1 (CB1KO) and CB2 cannabinoid receptors (CB2KO) and transgenic mice overexpressing CB2 receptors (CB2xP). ⋯ All mouse lines developed similar histological changes after MIA intra-articular injection. Nevertheless, MIA intra-articular injection produced specific changes in the expression of cannabinoid and opioid receptor genes in lumbar spinal cord sections that were further modulated by the genetic alteration of the cannabinoid receptor system. These results revealed that CB2 receptor plays a predominant role in the control of joint pain manifestations and is involved in the adaptive changes induced in the opioid system under this pain state.
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The objectives of this study were to examine whether (1) daily pain-related changes in physical functioning differed between happily partnered, unhappily partnered, and unpartnered female chronic pain patients, and (2) affect and pain cognitions mediated the partner status effect on pain-related changes in physical functioning. Two hundred fifty-one women with chronic pain due to osteoarthritis and/or fibromyalgia completed 30 daily electronic diaries assessing pain, affect, pain-related cognitions, and physical functioning. Patients living with a romantic partner also completed a modified version of the Locke-Wallace Marital Adjustment Scale to assess relationship satisfaction. ⋯ The impact of relationship status on pain-related changes in physical functioning was partly mediated by the pain cognitions catastrophizing and coping difficulty. These results indicate that happily partnered pain patients show less pain-related physical disability and more adaptive affective and cognitive responses to daily pain changes than do unhappily partnered and unpartnered patients. Living in a happy union may bolster the capacity of patients to sustain a sense of pain coping efficacy during pain episodes, which in turn, minimizes pain-related physical activity limitations.
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Despite well-documented racial disparities in prescribing opioid medications for pain, little is known about whether there are disparities in the monitoring and follow-up treatment of patients who are prescribed opioid medications. We conducted a retrospective cohort study to examine whether there are racial differences in the use of recommended opioid monitoring and follow-up treatment practices. Our sample included 1646 white and 253 black patients who filled opioid prescriptions for noncancer pain for ≥ 90 consecutive days at the Veterans Affairs Pittsburgh Healthcare System pharmacy in fiscal years 2007 and 2008. ⋯ Among those who had at least 1 urine drug test, black patients were subjected to more tests, especially if they were on higher doses of opioids. Compared with white patients, black patients were less likely to be referred to a pain specialist and more likely to be referred for substance abuse assessment. Addressing disparities in opioid monitoring and follow-up treatment practices may be a previously neglected route to reducing racial disparities in pain management.
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Drug-resistant chronic cluster headache (CH) is an unremitting illness with excruciatingly severe headaches that occur several times daily. Starting in 2000, a total of 19 patients with long-lasting chronic CH, with multiple daily attacks unresponsive to all known prophylactics, received stimulation of the posterior inferior hypothalamic area ipsilateral to the pain as treatment. We report long-term follow-up (median 8.7 years, range 6-12 years) in 17 patients. ⋯ This exceptionally long follow-up shows that hypothalamic stimulation for intractable chronic CH produces long-lasting improvement in many patients. Previous experience was limited to a median of 16 months. Important new findings are as follows: stimulation is well tolerated for many years after implantation; after several years during which stimulation was necessary for relief, a persistent almost pain-free condition can be maintained when stimulation is off, suggesting that hypothalamic stimulation can change disease course; tolerance can occur after marked long-lasting improvement; and bilateral chronic CH seems to predict poor response to hypothalamic stimulation.