Pain
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The effects of nitrous oxide (N2O) are thought to be mediated by several pharmacological pathways at different levels of the central nervous system. Here, we focus on excitatory glutamatergic transmission in the superficial dorsal horn of the spinal cord with respect to its importance for the nociceptive processing. The effects of 50% N2O on electrically evoked and spontaneous excitatory glutamatergic transmission and on the response to exogenous administration of N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-4-propionic acid (AMPA) receptor agonists were examined in lamina II neurons of adult rat spinal cord slices using the whole-cell patch-clamp technique. ⋯ Moreover N2O changed the distribution of miniature EPSC amplitude, but not frequency distribution in most neurons. N2O inhibits glutamatergic transmission in the superficial dorsal horn by modulating the NMDA- and AMPA-receptors. Our findings raise the possibility that the antinociceptive effect of N2O may be directly mediated at the level of the spinal cord.
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Comparative Study
The inventory of parent/caregiver responses to the children's pain experience (IRPEDNA): development and preliminary validation.
This paper describes the development and preliminary validation of a self-administered instrument designed to measure parents/caregivers' responses to children's pain episodes. For empirical validation purposes, a 60-item inventory was answered by 401 adults whose children's ages ranged from 6 to 16 years (mean=10.44, and SD=2.25 years). Factor structure and item analyses led to a 37 item inventory with three interrelated scales, namely: solicitousness (n=15 items), discouragement (n=10 items), and promotion of well-behaviors and coping (n=12 items). The three scales had good internal consistency, with coefficient alphas of 0.87, 0.83 and 0.87, respectively; they also showed good criterion-related validity.
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Comparative Study
Expressive dimensions of pain catastrophizing: a comparative analysis of school children and children with clinical pain.
We investigated the role of the child's pain catastrophizing in explaining (1) children's self-reported tendency to verbally share their pain experience with others and (2) different dimensions of pain expression, as described by the mother and the father, including non-verbal and verbal communicative pain behaviour and protective pain behaviour. Participants were school children, children with chronic or recurrent pain, and their parents. ⋯ These results further corroborate the position that catastrophic thoughts about pain have interpersonal consequences. Findings are discussed in terms of the possible functions and effects upon others of pain catastrophizing and associated categories of pain behaviour.
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Comparative Study
Visceral and somatic hypersensitivity in a subset of rats following TNBS-induced colitis.
Chronic abdominal pain is one of the most common gastrointestinal symptoms experienced by patients. Visceral hypersensitivity has been shown to be a biological marker in many patients with chronic visceral pain. We have previously shown that IBS patients with visceral hypersensitivity also have evidence of thermal hyperalgesia of the hand/foot. ⋯ Transient colonic inflammation leads to chronic visceral and somatic hypersensitivity in a subset of rats. These findings are similar to the subset of patients who develop chronic gastrointestinal symptoms following enteric infection.
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Comparative Study
Activation of the 5-HT1B/D receptor reduces hindlimb neurogenic inflammation caused by sensory nerve stimulation and capsaicin.
Activation of the 5-HT(1B/D) receptor inhibits cerebrovascular neurogenic inflammation (NI). The aim of this study was to determine if the 5-HT(1B/D) receptor agonist sumatriptan can also inhibit NI in other regions of the body. NI was assessed by measuring plasma extravasation (PE) and changes in blood flow in the rat hindpaw. ⋯ The systemic and local inhibitory actions of sumatriptan are mediated by the 5-HT(1B/D) receptor as pre-treatment with the 5-HT(1B/D) antagonist GR127935 (GR; 15 microl, 1 microM, s.c. or 0.2 micromol/kg, i.v.) completely blocked the inhibitory effect of sumatriptan on capsaicin-induced vasodilation and reduced the inhibitory effect of sumatriptan on capsaicin and electrically induced-PE. Neither PE induced by local injection of substance P (SP) (20 pmol, 20 microl, s.c.) nor vasodilation induced by local CGRP injection was affected by pre-treatment with sumatriptan. These findings indicate that both local and systemic activation of the 5-HT(1B/D) receptor by sumatriptan reduce NI induced by nerve stimulation or capsaicin presumably by inhibiting neuropeptide release. 5-HT(1B/D) receptor agonists may be useful for the treatment of non-trigeminal pain conditions involving NI.