Pain
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Considerable research links chronic pain to autonomic nervous system (ANS) dysfunction, specifically low heart rate variability (HRV) mediated by reduced parasympathetic activity. However, little is known about factors that influence ANS function in chronic pain. The ANS is the primary pathway for brain-gut communication, making it of particular interest in gastrointestinal disorders, such as irritable bowel syndrome, characterized by functional abdominal pain (FAP). ⋯ Spectral analysis of electrocardiogram showed that Pain-Persist females had reduced power in the high frequency domain of cardiac activity, ie, reduced parasympathetic "braking" of sympathetic activity, both at rest and during stress. Pain-Remit females exhibited levels of autonomic imbalance intermediate between those of females with persistent FAP and all other participants. Parasympathetically mediated low HRV in young women with persistent FAP may reflect a peripheral mechanism (eg, gut dysfunction) or a central nervous system mechanism (eg, pain amplification or poor emotion self-regulation) involving prolonged sympathetic activation.
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The aim of this study was to examine a possible relationship between early puberty and chronic nonspecific pain in 13- to 18-year-old girls. All adolescents in Nord-Trøndelag County, Norway, were invited to participate in the Young-HUNT3 study (2006-2008). Of the invited girls, 81% answered the questionnaire and of these 3982 were 13 to 18 years of age. ⋯ A similar association was found between girls that perceived themselves as earlier physically matured than their peers and chronic nonspecific pain. Headache/migraine was the most common type of chronic nonspecific pain regardless of menarcheal age. In all reported locations, pain was more prevalent in the group with early menarche compared to normal or late menarche.
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Toll-like receptor 7 (TLR7) is associated with the pathophysiology of systemic lupus erythematosus and Sjögren syndrome, well-known diseases accompanying interstitial cystitis (IC). We studied TLR7 expression in the bladder of patients with Hunner-type IC (HIC) and its functional roles in bladder inflammation and nociception using mice. Bladder biopsy specimens were obtained from patients with HIC. ⋯ Hydroxychloroquine reversed the LX-induced cystometric and voiding behavioral changes. Toll-like receptor 7 was up-regulated in the bladder mucosa of patients with HIC, and activation of TLR7 in the mouse bladder induced cystitis with sensory hyperactivity of the bladder. Blocking the TLR7 pathway may be an innovative treatment target of HIC.
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The primary aim of this study was to evaluate activity rhythms in fibromyalgia syndrome (FMS) and their association with FMS-related symptoms. We hypothesized that stronger and more consistent activity rhythms would be associated with reduced symptom severity and presentation in FMS. Two hundred ninety-two patients with FMS (mean age = 45.1 ± 11.1; 272 women) provided a 7-day actigraphy recording and responses to questionnaires addressing degree of pain, fatigue, mood, and physical impairment. ⋯ Each activity parameter provided unique discrimination of the clinical set by multivariate test (P = 0.003, 0.018, and 0.007 for Amplitude, Phi, and Mesor, respectively). These results revealed that better pain, fatigue, mood, physical impairment, and sleep outcomes were associated with higher activity range and more rhythmicity (Amplitude), increased mean activity (Mesor), and with earlier timing of peak activity (Phi). Exploratory analyses revealed significantly worse sleep for individuals with low Amplitude and more delayed Phi.
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Pain spontaneously activates adaptive and dynamic learning processes affecting the anticipation of, and the responses to, future pain. Computational models of associative learning effectively capture the production and ongoing changes in conditioned anticipatory responses (eg, skin conductance response), but the impact of this dynamic process on unconditional pain responses remains poorly understood. Here, we investigated the dynamic modulation of pain and the nociceptive flexion reflex by fear learning in healthy human adult participants undergoing a classical conditioning procedure involving an acquisition, reversal and extinction phase. ⋯ Moderation analyses further showed that hyperalgesic effects of associability were larger in individuals reporting more harm vigilance and less emotional detachment. Higher harm vigilance was also associated with a stronger mediation of hyperalgesic effects by spinal processes. These results demonstrate how dynamic changes in pain can be explained by associative learning theory and that resilient attitudes towards fear/pain can attenuate the adverse impact of adaptive aversive learning processes on pain.