Pain
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The effects of electrical stimulation of cervical vagal afferents (VAS) on the background activity and on the responses of 25 spinothalamic tract (STT) neurons to noxious stimuli were studied in anesthetized rats. Background (spontaneous) activity of 9 (36%) STT neurons was inhibited by all intensities of VAS. 6 (24%) units were facilitated at lesser and inhibited at greater intensities of VAS, 5 (20%) units were only facilitated by all intensities of VAS, and 5 (20%) units were not affected by VAS. ⋯ There were no significant differences in VAS-produced modulatory effects between STT neurons and 16 unidentified lumbar spinal dorsal horn neurons studied under the same conditions. These results reveal that descending facilitatory and inhibitory pathways engaged by activation of vagal afferents modulate rostrally projecting nociceptive transmission neurons in the spinal cord, constituting an important regulatory network for nociception.
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This in-depth study examines the relationships between patient, stimulator and outcome variables in a large number of chronic pain patients utilising TENS on a long-term basis. 179 patients completed a TENS questionnaire designed to record age, sex, cause and site of pain and TENS treatment regime. Of these 179 patients, 107 attended our research unit for assessment of the electrical characteristics of TENS during self-administered treatment. Although a remarkable lack of correlation between patient, stimulator and outcome variables was found to exist, the analysis revealed much information of importance: 47% of patients found TENS reduced their pain by more than half; TENS analgesia was rapid both in onset (less than 0.5 h in 75% patients) and in offset (less than 0.5 h in 51% patients); one-third of patients utilised TENS for over 61 h/week; pulse frequencies between 1 and 70 Hz were utilised by 75% of patients; 44% of patients benefitted from burst mode stimulation. The clinical implications of these findings are discussed.
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Acupuncture was given to patients before (preoperative-acupuncture group, PRE-ACU, n = 25) or after (postoperative-acupuncture group, POST-ACU, n = 25) operative removal of impacted mandibular third molars. Sixty patients did not receive acupuncture and participated as a control group (CG). All patients completed a questionnaire in order to characterize state tension and stress, degrees of neuroticism, extroversion, depression and psychosomatic disorders. ⋯ A significantly larger number of patients suffering from "dry socket" (a complication during wound healing) was found in both PRE- and POST-ACU compared with the CG. No correlation was found between assessed personality characteristics and reported postoperative pain/consumption of analgesics in any group and could thus not explain the observed differences between the groups. The reason for our unexpected "negative" findings is unclear but some hypothetical explanations are discussed.
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This study compared pain perception in young male and female subjects, using experimental noxious heat stimuli. During 2 sessions, each of 40 subjects rated the magnitude of 120 heat stimuli, ranging from 45 degrees C to 50 degrees C. The study included a comparison of visual analogue and magnitude matching rating procedures, as well as a test of simulated analgesia, in which the range of stimuli presented during the 2 experimental sessions was shifted by 1 degree C. ⋯ In addition, the data suggest that females discriminate among the painful heat intensities better than males. For example, female subjects showed significant between-session discrimination of noxious heat stimuli, while male subjects did not, and females produced steeper within-session stimulus-response functions than did males. These observed differences in nociceptive discrimination between males and females indicate that the sex-related variation in pain perception is probably related to sensory factors rather than differences in attitude or emotional response.