Pain
-
The generation of transgenic mice that lack or overexpress genes relevant to pain is becoming increasing common. However, only one visceral pain model, the writhing test, is widely used in mice. Here we describe a novel model, chemical stimulation of the colon, which we have developed in mice. ⋯ The peak behavioural responses were evoked by 0.1% capsaicin and by 1% mustard oil respectively. The nociceptive behavioural responses were dose-dependently reversed by morphine (ED50 = 1.9 +/- 1 mg/kg s.c.). We conclude that this model represents a useful tool both for phenotyping mutant mice and for classical pharmacology since information on visceral pain, referred hyperalgesia and colon inflammation can all obtained from the same animal.
-
Randomized Controlled Trial Comparative Study Clinical Trial
The analgesic effect of codeine as compared to imipramine in different human experimental pain models.
The hypoalgesic effect of single oral doses of 100 mg imipramine and 125 mg codeine was evaluated in a randomised, placebo-controlled, double-blind, 3-way cross-over experiment including 18 healthy volunteers. Pain tests were performed before and 90, 180, 270, 360 and 450 min after medication. The tests included determination of pain tolerance thresholds to pressure, pain detection/tolerance thresholds to single electrical sural nerve stimulation and pain summation at tolerance threshold to repetitive electrical sural nerve stimulation (temporal summation) and pain experienced during the cold pressor test, rated as peak pain intensity, pain average intensity and discomfort. ⋯ Pain summation may be a key mechanism in neuropathic pain. Imipramine has a documented effect on such pain conditions on temporal summation. The present study showed that codeine also inhibits temporal summation, which is in line with the clinical observations indicating that opioids relieve neuropathic pain.
-
Review Clinical Trial
Microsurgical DREZotomy for pain due to spinal cord and/or cauda equina injuries: long-term results in a series of 44 patients.
According to the literature estimations, 10-25% of patients with spinal cord and cauda equina injuries eventually develop refractory pain. Due to the fact that most classical neurosurgical methods are considered of little or no efficacy in controlling this type of pain, the authors had recourse to microsurgery in the dorsal root entry zone (DREZ). This article reports on the long-term results of the microsurgical approach to the dorsal root entry zone (DREZotomy) in a series of 44 patients suffering from unbearable neuropathic pain secondary to spine injury. ⋯ There were no perioperative mortalities. Morbidity included cerebrospinal fluid leak (three patients), wound infection (two patients), subcutaneous hematoma (one patient) and bacteremia (in one patient). The above data justify the inclusion of DREZ-lesioning surgery in the neurosurgical armamentarium for treating 'segmental' pain due to spinal cord injuries.
-
Randomized Controlled Trial Clinical Trial
The roles of beliefs, catastrophizing, and coping in the functioning of patients with temporomandibular disorders.
Pain-related beliefs, catastrophizing, and coping have been shown to be associated with measures of physical and psychosocial functioning among patients with chronic musculoskeletal and rheumatologic pain. However, little is known about the relative importance of these process variables in the functioning of patients with temporomandibular disorders (TMD). To address this gap in the literature, self-report measures of pain, beliefs, catastrophizing, coping, pain-related activity interference, jaw activity limitations, and depression, as well as an objective measure of jaw opening impairment, were obtained from 118 patients at a TMD specialty clinic. ⋯ Controlling for age, gender, pain intensity, and the other process variables, significant associations were found between (1) beliefs and activity interference and depression, and (2) catastrophizing and depression. No process variable was associated significantly with the objective measure of jaw impairment. The results suggest that for patients with moderate or high levels of TMD pain and dysfunction, beliefs about pain play an important role in physical and psychosocial functioning.
-
Randomized Controlled Trial Clinical Trial
The effects of failure feedback and pain-related fear on pain report, pain tolerance, and pain avoidance in chronic low back pain patients.
The aim of this study was to investigate the influence of non-pain-related failure experiences and pain-related fear on pain report, pain tolerance and pain avoidance in chronic low back pain (CLBP) patients. Moreover, the mediating and moderating role of negative affectivity (trait-NA) in the relationship between failure experiences and pain was examined. Seventy-six patients were divided into high and low pain-related fear groups and within each group they were randomly assigned to the failure or success feedback condition. ⋯ Pain-related fear did not predict pain avoidance when pre-lifting pain and gender were controlled for. Finally, pre-lifting pain turned out to be the strongest predictor with regard to all pain measures. The role of pain-related fear and unexpected findings with regard to feedback are discussed as well as some clinical implications.