Pain
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Comparative Study
Self-medication of a cannabinoid CB2 agonist in an animal model of neuropathic pain.
Drug self-administration methods were used to test the hypothesis that rats would self-medicate with a cannabinoid CB(2) agonist to attenuate a neuropathic pain state. Self-medication of the CB(2) agonist (R,S)-AM1241, but not vehicle, attenuated mechanical hypersensitivity produced by spared nerve injury. Switching rats from (R,S)-AM1241 to vehicle self-administration also decreased lever responding in an extinction paradigm. (R,S)-AM1241 self-administration did not alter paw withdrawal thresholds in sham-operated or naive animals. ⋯ Our results suggest that cannabinoid CB(2) agonists may be exploited to treat neuropathic pain with limited drug abuse liability and central nervous system side effects. These studies validate the use of drug self-administration methods for identifying nonpsychotropic analgesics possessing limited abuse potential. These methods offer potential to elucidate novel analgesics that suppress spontaneous neuropathic pain that is not measured by traditional assessments of evoked pain.
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Comparative Study
Effects of self-discrepancies on activity-related behaviour: explaining disability and quality of life in patients with chronic low back pain.
In chronic low back pain (CLBP) research, the self-discrepancy model has been applied to explain dysfunctional avoidance and persistence behaviour. The main aim of this study was to evaluate whether specific self-discrepancies in patients with CLBP are associated with the abovementioned types of activity-related behaviour and whether changes in self-discrepancies over time are associated with changes in activity-related behaviour. Furthermore, the aim was to evaluate whether avoidance and persistence behaviour are associated with a higher level of disability and a diminished quality of life and whether changes over time in avoidance and persistence behaviour result in changes in disability and quality of life. ⋯ Results indicate that patients with CLBP who feel closer to their ideal-other show more characteristics of persistence behaviour. Patients who move further away from their ideal-own also show more characteristics of persistence behaviour. Furthermore, in patients characterized as avoider, a decrease in a patient's daily uptime was associated with a decrease of mental health-related quality of life.
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Patients with chronic pain conditions demonstrate altered central processing of experimental noxious stimuli, dysfunction of the hypothalamic-pituitary-adrenal axis, and reduced quality of life. Dysmenorrhoea is not considered a chronic pain condition, but is associated with enhanced behavioural responses to experimental noxious stimuli. We used behavioural measures, functional magnetic resonance imaging, and serum steroid hormone levels to investigate the response to experimental thermal stimuli in otherwise healthy women, with and without dysmenorrhoea. ⋯ Thus, many features of chronic pain conditions are also seen in women with dysmenorrhoea: specifically a reduction in quality of life, suppression of the hypothalamic-pituitary-adrenal axis, and alterations in the central processing of experimental noxious stimuli. These alterations persist when there is no background pain and occur in response to stimuli at a site distant from that of the clinical pain. These findings indicate the potential importance of early and adequate treatment of dysmenorrhoea.