Pain
-
In the peripheral nervous system, N-methyl-D-aspartate receptors (NMDAR) expressed on the central and peripheral terminals of primary afferent neurons are involved in nociception. We used single cell imaging of intracellular calcium concentration ([Ca2+]i) and patch clamp techniques to characterize the functional properties of NMDARs on adult rat dorsal root ganglia (DRG) neurons in primary culture and selectively on those innervating the distal colon. In Mg2+-free extracellular solution, rapid perfusion of DRG neurons with 250 microM NMDA and 10 microM glycine caused a significant increase in [Ca2+]i, and elicited inward currents in whole cell patch clamp recordings when the holding potential was -60 mV. ⋯ There was no evidence of multiple binding sites for ifenprodil. There was no significant difference in the NMDAR current density on DRG neurons that had innervated the colon, nor was there a difference in the EC50 for ifenprodil. These results demonstrate that functional NMDARs expressed by DRG neurons innervating both somatic and visceral tissues of adult rats are composed predominantly of NR2B subunits.
-
Diabetes can induce a bewildering list of sensory changes, including alteration in pain sensitivity. Painful diabetic neuropathy is refractory to most common analgesics. This study examined the effect of a p38alpha MAPK inhibitor, SD-282, on mechanical allodynia, thermal hyperalgesia, and formalin-evoked nociception in streptozotocin-induced diabetic rats. ⋯ Repeated administration of 45 mg/kg SD-282 attenuated flinching behaviors during the quiescent period and the second phase of the formalin response in diabetic rats. Acute and repeated administration of 15 or 45 mg/kg SD-282 had no effect on mechanical, thermal or formalin responses in age-matched control rats. These results indicate a potential therapeutic value of p38alpha MAPK inhibitors in the treatment of aberrant pain sensitivity produced by diabetes.
-
Randomized Controlled Trial Comparative Study Clinical Trial
A double-blind placebo-controlled comparison of tramadol/acetaminophen and tramadol in patients with postoperative dental pain.
The objective of this study was to compare the analgesic efficacy of tramadol/acetaminophen (APAP) (total dose 75 mg/650 mg) and tramadol (total dose 100 mg) for the control of pain after oral surgery. A total of 456 patients with moderate-to-severe pain within 5 h after extraction of two or more third molars were randomized to receive two identical encapsulated tablets containing tramadol/APAP 37.5 mg/325 mg, tramadol 50 mg, or placebo. ⋯ The most common adverse events with active treatment were nausea, dizziness, and vomiting; these events occurred more frequently in the tramadol group than in the tramadol/APAP group. This study established the superiority of tramadol/APAP 75 mg/650 mg over tramadol 100 mg in the treatment of acute pain following oral surgery.
-
Single-dose clinical trial methods for evaluating analgesics have been used successfully for over 50 years. The aims of this review were to examine which pain measurement scales have been used in high quality acute pain trials, to investigate other common measurements or characteristics, to confirm that different scales used by standard methods give the same estimate of analgesic effect, to investigate remedication methodologies and the potential of 'time to remedication' as a standard outcome. Published reports of randomised, double blind, placebo-controlled trials, investigating at least 20 adult patients (10 patients per treatment arm) experiencing moderate or severe pain using at least one standard pain intensity or pain relief scale were sought. ⋯ Possible improvements include reporting the number of patients with certain levels of pain relief, or the actual number (percentage) of patients with a certain level of pain relief at a certain time, or more useful information on remedication from trials of at least 12 h duration. Most useful would be all three. Further exploration would only be possible from analysis at the individual patient level.
-
Recurrent pain in childhood are common and frequently impact children's everyday functioning. However, there are currently limited tools available to measure the impact of recurrent pain on children's daily activities, in particular, that can be used to identify appropriate targets for intervention and measure response to such interventions. The purpose of this study was to develop and validate a new measure, the Child Activity Limitations Interview (CALI), to improve the assessment of functional impairment due to recurrent pain in school-age children and adolescents, and to compare this measure to the Functional Disability Inventory. ⋯ One-month test-retest reliability (r = 0.33, child report) and cross-informant reliability (r = 0.43) were moderate. Results demonstrate support for face, construct, and concurrent validity as well as responsiveness to pain symptom fluctuation. Findings demonstrate that the CALI is a promising measure for assessing and monitoring subjective report of functional impairment in school-age children and adolescents with recurrent and chronic pain.