Pain
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Comparative Study
The role of neuroticism, pain catastrophizing and pain-related fear in vigilance to pain: a structural equations approach.
The present study aimed at clarifying the precise role of pain catastrophizing, pain-related fear and personality dimensions in vigilance to pain and pain severity by means of structural equation modelling. A questionnaire survey was conducted in 122 patients with chronic or recurrent low back pain. Results revealed that pain catastrophizing and pain-related fear mediated the relationship between neuroticism and vigilance to pain. ⋯ Finally, we found that neuroticism moderated the relationship between pain severity and catastrophic thinking about pain. The results strongly support the idea that vigilance to pain is dependent upon catastrophic thinking and pain-related fear. Neuroticism is best conceived of as a vulnerability factor; it lowers the threshold at which pain is perceived as threatening, and at which catastrophic thoughts about pain emerge.
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Comparative Study
Comprehensive description of newborn distress behavior in response to acute pain (newborn male circumcision).
One of the most difficult challenges still facing researchers and clinicians is assessing pain in the newborn. Behaviors provide one of the most promising avenues for deepening our fundamental understanding of complex phenomenon like newborn pain, and are key to developing descriptive-level knowledge to further newborn pain assessment efforts. In this ethologically based research, we report on the duration and frequency of neonatal distress behavior to seven distinct noxious and non-noxious but distress-provoking events including baseline (diaper change, post-diaper change, application of arm and leg restraints, post-application of arm and leg restraints, circumcision, post-circumcision) associated with newborn surgical pain. ⋯ This led to the identification of (1) 40 distress behaviors as they occurred along the continuum of distress, (2) eight distress behaviors specific to surgery, (3) 11 classes of behaviors occurring within the five sub-phases of circumcision, and (4) a description of 25 distinct post-distress behaviors. Findings support the ability to distinguish distress behaviors specific to pain and the ability to detect prolonged distress as well as individual differences in distress-related pain expression. Findings also justify ongoing use of ethological approaches to further newborn pain assessment and to investigate poorly understood topics such as infant self-regulation within the context of pain (pain recovery).
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Cannabinoid receptor agonists produce analgesia for pains of non-cranial origin. However, their effectiveness for craniofacial pains is currently unclear. In the present study, the cannabinoid CB1/CB2 receptor agonist, WIN 55,212-2 (WIN), was bath applied to the brainstem while activity of spinal trigeminal nucleus caudalis (Vc) neurons evoked by transcutaneous electrical stimulation was recorded in isoflurane anesthetized rats. ⋯ SR141716A, a CB1 receptor antagonist, prevented the effects of WIN on WDR PDC and LTM Abeta evoked activity. These results indicate that cannabinoid receptor agonists may be effective agents for craniofacial pain. Furthermore, the particular sensitivity of PDC activity, a measure of neuronal hyperexcitability, to cannabinoid receptor agonists may be relevant to the treatment of persistent craniofacial pain.
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Botulinum toxin type A (BoNT-A) produced by the bacterium Clostridium botulinum is a potent inhibitor of acetylcholine release in the neuromuscular junction and has been used to treat many disorders related to excessive muscle contraction. However, BoNT-A has recently been used in pain therapy to treat myofascial pain, low back pain and various types of headaches, including migraine. The purpose of this study is to investigate the antinociceptive effect of BoNT-A and its underlying mechanism in the rat formalin inflammatory pain model. ⋯ Pre-treatment of rats with BoNT-A (3.5, 7 or 15 U/kg) all significantly reduced formalin-evoked glutamate (Glu) release. These results demonstrate that local peripheral injection of BoNT-A significantly reduces formalin-induced nociceptive behaviors with the absence of obvious muscle weakness. Such an antinociceptive effect of BoNT-A is associated with the inhibition of formalin-induced release of Glu (and/or neuropeptides) from primary afferent terminals.