The journal of pain : official journal of the American Pain Society
-
A growing body of research has identified fear of visceral sensations as a potential mechanism in the development and maintenance of visceral pain disorders. However, the extent to which such learned fear affects visceroception remains unclear. To address this question, we used a differential fear conditioning paradigm with nonpainful esophageal balloon distensions of 2 different intensities as conditioning stimuli (CSs). ⋯ Analyses of galvanic skin and startle eyeblink responses as physiological markers of successful conditioning showed increased fear responses to the CS+ compared with the CS-, but only in the group with the low-intensity stimulus as CS+. Computational modeling of response times and response accuracies revealed that differential fear learning affected perceptual decision-making about the intensities of visceral sensations such that sensations were more likely to be categorized as more intense. These results suggest that associative learning might indeed contribute to visceral hypersensitivity in functional gastrointestinal disorders.
-
Few studies have examined the underlying psychosocial mechanisms of pain in Asian Americans. Using the biopsychosocial model, we sought to determine whether variations in depression contribute to racial group differences in symptomatic knee osteoarthritis pain between Asian Americans and non-Hispanic white Americans. The sample consisted of 100 participants, including 50 Asian Americans (28 Korean Americans, 9 Chinese Americans, 7 Japanese Americans, 5 Filipino Americans, and 1 Indian American) and 50 age- and sex-matched non-Hispanic white Americans with symptomatic knee osteoarthritis pain. The Centers for Epidemiologic Studies Depression Scale was used to assess symptoms of depression, and the Western Ontario and McMaster Universities Osteoarthritis Index and the Graded Chronic Pain Scale were used to measure clinical pain. In addition, quantitative sensory testing was used to measure experimental sensitivity to heat- and mechanically-induced pain. The results indicated that higher levels of depression in Asian Americans may contribute to greater clinical pain and experimental pain sensitivity. These findings add to the growing literature regarding ethnic and racial differences in pain and its associated psychological conditions, and additional research is warranted to strengthen these findings. ⋯ This article shows the contribution of depression to clinical pain and experimental pain sensitivity in Asian Americans with knee osteoarthritis. Our results suggest that Asian Americans have higher levels of depressive symptoms and that depression plays a relevant role in greater clinical pain and experimental pain sensitivity in Asian Americans.
-
Parents play an important role in supporting school functioning in youth with chronic pain, but no validated tools exists to assess parental responses to child and adolescent pain behaviors in the school context. Such a tool would be useful in identifying targets of change to reduce pain-related school impairment. The goal of this study was to develop and preliminarily validate the Parent Responses to School Functioning Questionnaire (PRSF), a parent self-report measure of this construct. ⋯ Criterion validity was demonstrated by significant correlations with school absence rates and overall school functioning, and construct validity was demonstrated by correlations with general parental responses to pain. Three subscales emerged capturing parents' personal distress, parents' level of distrust of the school, and parents' expectations and behaviors related to their child's management of challenging school situations. These results provide preliminary support for the PRSF as a psychometrically sound tool to assess parents' responses to child pain in the school setting.
-
Upon systemic administration in rats, the prodrug L-4-chlorokynurenine (4-Cl-KYN; AV-101; VistaGen Therapeutics, Inc, South San Francisco, CA) is rapidly absorbed, actively transported across the blood-brain barrier, and converted in astrocytes to 7-chlorokynurenic acid (7-Cl-KYNA), a potent and specific antagonist of the glycine B coagonist site of the N-methyl-D-aspartate (NMDA) receptor. We examined the effects of 4-Cl-KYN in several rat models of hyperalgesia and allodynia and determined the concentrations of 4-Cl-KYN and newly produced 7-Cl-KYNA in serum, brain, and spinal cord. ⋯ Our conclusions show that after systemic delivery, the highest 2 doses (167 and 500 mg/kg) of 4-Cl-KYN yielded brain concentrations of 7-Cl-KYNA exceeding its half maximal inhibitory concentration (IC50) at the glycine B site and resulted in dose-dependent antihyperalgesia in the 4 models of facilitated processing associated with tissue inflammation and nerve injury. On the basis of the relative dose requirements for analgesic actions and side effect profiles from these experiments, 4-Cl-KYN is predicted to have antihyperalgesic efficacy and a therapeutic ratio equal to gabapentin and superior to MK-801.
-
Pain after surgery remains a problem worldwide, although there are no published data on postoperative outcomes in Spain. We evaluated 2,922 patients on the first day after surgery in 13 tertiary care Spanish hospitals, using the PAIN-OUT questionnaire. The aims were to: assess postoperative outcomes and anesthetic/analgesic management in Orthopedics (ORT) and General Surgery (GEN) patients; explore the influence of the analgesic therapy on outcomes and opioid requirements; evaluate and compare outcomes and analgesic management according to surgical procedure. ⋯ Presurgical chronic pain (>7) and/or chronic opioid consumption, were associated with worsened pain outcomes; the latter with a 50% increase in postoperative opioid requirements. Tibia/fibula and foot surgeries (ORT), and gastric, small intestine, and anterior abdominal wall procedures (GEN) were the most painful. Rigorous control of chronic pain before surgery, and combining opioids with adjuvants and other analgesics perioperatively, might improve postoperative outcomes.