Pain
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There has been a recent increase in public and professional concern about the prescription of strong prescription opioids for pain. Despite this concern, research to date has been limited because of a number of factors such as small sample sizes, exclusion of people with complex comorbidities, and studies of short duration. The Pain and Opioids IN Treatment is a 2-year prospective cohort study of 1500 people prescribed with pharmaceutical opioids for their chronic pain. ⋯ The younger groups experienced higher levels of pain and pain interference, more mental health and substance use issues, and barriers to treatment, compared with the older group. This study found that the people who have been prescribed strong opioids for chronic pain have very complex demographic and clinical profiles. Major age-related differences in the experiences of pain, coping, mental health, and substance use suggest the necessity of differential approaches to treatment.
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Persistent postoperative pain is a well-established clinical problem with potential severe personal and socioeconomic implications. The prevalence of persistent pain varies across surgery types. Severe persistent pain and related impairment occur in 5% to 10% of patients after groin hernia repair. ⋯ For GCH1, the A allele of SNP rs3783641, T allele of rs8007267, and AT haplotype showed a protective effect trend (although nonsignificant; P = 0.08, 0.06, and 0.08, respectively). A prediction model of substantial PPP-related activity impairment, combining COMT and GCH1 SNPs with clinical, psychophysical, and psychological risk factors, had a "good" (0.8 < area under curve < 0.9) discriminatory power. These data suggest that functional variations in COMT and GCH1 combined with clinical factors are predictive of PPP-related impairment after groin herniotomy.
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Central dopamine and norepinephrine regulate behavioral and physiological responses during rewarding and aversive stimuli. Here, we investigated and compared norepinephrine and dopamine transmission in 2 limbic structures, the ventral bed nucleus of the stria terminalis and the nucleus accumbens shell of anesthetized rats, respectively, in response to acute tail pinch, a noxious stimulus. Norepinephrine release in the ventral bed nucleus of the stria terminalis responded monophasically, increasing at the time of the tail pinch and remaining elevated for a period after its cessation. ⋯ At the termination of the stimuli, however, extracellular dopamine either recovered back to or spiked above the initial baseline concentration. These signaling patterns were more clearly observed after administration of selective catecholamine autoreceptor and transporter inhibitors. The results suggest that the opposing responses of these catecholamines can provide integration of noxious inputs to influence behavioral outputs appropriate for survival such as escape or fighting.