The journal of pain : official journal of the American Pain Society
-
Stress-induced hyperalgesia (SIH), a common clinical observation associated with multiple painful diseases including functional urinary disorders, presently has no mechanistic explanation. Using a footshock treatment, a classic stressor, to magnify physiological responses in a model of urinary bladder pain, we examined one potential group of mediators of SIH, the corticotropin-releasing factor (CRF)-related neuropeptides. Exposure to a footshock treatment produced bladder hypersensitivity in female Sprague-Dawley rats, manifested as significantly more vigorous visceromotor responses (VMRs) to urinary bladder distension (UBD) compared with rats that were exposed to a non-footshock treatment. This bladder hypersensitivity was significantly attenuated by blocking spinal CRF(2) receptors but not CRF(1) receptors. Furthermore, spinal administration of urocortin 2, a CRF(2) receptor agonist, augmented UBD-evoked VMRs in a way similar to what was observed after exposure to Footshock, an effect significantly attenuated by pretreatment with spinal aSVG30, a CRF(2) receptor antagonist. Surprisingly, neither spinal administration of CRF nor the CRF(1) receptor antagonist antalarmin had an effect on bladder nociceptive responses. The results of the present study not only provide further support for a role of stress in the exacerbation of bladder pain but also implicate spinal urocortins and their endogenous receptor, the CRF(2) receptor, as potential mediators of this effect. ⋯ This study presents evidence that spinal urocortins and CRF(2) receptors are involved in stress-induced hypersensitivity related to the urinary bladder. This provides a basis for investigating how urocortins mediate SIH, ultimately leading to more effective treatment options for patients with painful bladder syndromes as well as stress-exacerbated chronic pain.
-
Randomized Controlled Trial
Changes of hypertonic saline-induced masseter muscle pain characteristics, by an infusion of the serotonin receptor type 3 antagonist granisetron.
This study aimed to investigate whether granisetron reduces masseter muscle pain and allodynia induced by hypertonic saline. Fifteen healthy women and 15 age-matched healthy men participated in this randomized, placebo-controlled, double-blinded study. They first received bilateral injections of hypertonic saline into the masseter muscles (internal control). The evoked pain intensity and the pressure-pain threshold (PPT) were recorded during 30 minutes. Granisetron was then injected on one side and placebo (normal saline) on the contralateral side. Two minutes thereafter, the hypertonic saline injections were repeated. Pain and PPT were again recorded. The first injection of hypertonic saline induced pain of similar intensity, duration, and pain area on both sides, but with larger pain area in the women (P = .017). The PPT did not change significantly. The second injection of hypertonic saline induced considerably less pain (62.5%), of shorter duration (44.1%), and of smaller area (77.4%) on the side pretreated with granisetron (P = .005). The PPT was increased on the granisetron side in the men (P = .002). The results of this study show that local injection of a single dose of granisetron attenuates masseter muscle pain induced by hypertonic saline. ⋯ This article presents the changes of hypertonic saline-induced masseter muscle pain characteristics by infusion of granisetron. It appears that the pain-inducing effect in this experimental pain model is partly due to activation of 5-HT3-receptors. Hence, the results indicate that granisetron might offer a new treatment approach for localized myofascial pain.
-
Multicenter Study Comparative Study
Common chronic pain conditions in developed and developing countries: gender and age differences and comorbidity with depression-anxiety disorders.
Although there is a growing body of research concerning the prevalence and correlates of chronic pain conditions and their association with mental disorders, cross-national research on age and gender differences is limited. The present study reports the prevalence by age and gender of common chronic pain conditions (headache, back or neck pain, arthritis or joint pain, and other chronic pain) in 10 developed and 7 developing countries and their association with the spectrum of both depressive and anxiety disorders. It draws on data from 18 general adult population surveys using a common survey questionnaire (N = 42,249). Results show that age-standardized prevalence of chronic pain conditions in the previous 12 months was 37.3% in developed countries and 41.1% in developing countries, with back pain and headache being somewhat more common in developing than developed countries. After controlling for comorbid chronic physical diseases, several findings were consistent across developing and developed countries. There was a higher prevalence of chronic pain conditions among females and older persons; and chronic pain was similarly associated with depression-anxiety spectrum disorders in developed and developing countries. However, the large majority of persons reporting chronic pain did not meet criteria for depression or anxiety disorder. We conclude that common pain conditions affect a large percentage of persons in both developed and developing countries. ⋯ Chronic pain conditions are common in both developed and developing countries. Overall, the prevalence of pain is greater among females and among older persons. Although most persons reporting pain do not meet criteria for a depressive or anxiety disorder, depression/anxiety spectrum disorders are associated with pain in both developed and developing countries.
-
This study examined whether self-efficacy mediated the relationship between pain catastrophizing and pain and disability. Participants were 192 individuals diagnosed with osteoarthritis (OA) of the knees who were overweight or obese. Multiple mediator analyses were conducted to simultaneously test self-efficacy for pain control, physical function, and emotional symptoms as mediators while controlling for demographic and medical status variables. Higher pain catastrophizing was associated with lower self-efficacy in all 3 domains (Ps < .05). Self-efficacy for pain control fully mediated the relationship between pain catastrophizing and pain (beta = .08, Sobel test Z = 1.97, P < .05). The relationship between pain catastrophizing and physical disability was fully mediated by self-efficacy for physical function (beta = .06, Sobel test Z = 1.95, P = .05). Self-efficacy for emotional symptoms partially mediated the relationship between pain catastrophizing and psychological disability (beta = .12, Sobel test Z = 2.92, P < .05). These results indicate that higher pain catastrophizing contributed to greater pain and disability via lower domain-specific self-efficacy. Efforts to reduce pain and improve functioning in OA patients should consider addressing pain catastrophizing and domain specific self-efficacy. Pain catastrophizing may be addressed through cognitive therapy techniques and self-efficacy may be enhanced through practice of relevant skills and personal accomplishments. ⋯ This study found that higher pain catastrophizing contributed to greater pain and disability via domain specific self-efficacy. These results suggest that treatment efforts to reduce pain and improve functioning in OA patients who are overweight or obese should consider addressing both pain catastrophizing and self-efficacy.
-
Preoperative identification of patients at risk for high-intensity postoperative pain may be used to predict patients at risk for development of a persistent pain state and allocate patients to more intensive specific pain therapy. Preoperative pain threshold to electrocutaneus stimulation has recently been shown to correlate to acute postoperative pain after cesarean section, but the findings have not been confirmed in larger studies or other procedures. Preoperative electrical pain detection threshold and pain tolerance were assessed in patients undergoing a primary unilateral groin hernia repair. The correlation between the pain data for electrical stimulation was compared with the postoperative pain during the first week in 165 patients, whereof 3 were excluded. Preoperative electrical pain detection threshold and electrical pain tolerance threshold did not correlate to postoperative pain (rho = -0.13, P = .09, and rho = -1.2, P = .4, respectively. ⋯ Although preoperative electrical nociceptive stimulation may predict patients at risk of high-intensity acute pain after other surgical procedures, this was not the case in groin hernia repair patients receiving concomitant treatment with acetaminophen and ibuprofen.