Pain
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Randomized Controlled Trial
TRPV1 antagonistic analgesic effect: a randomized study of AZD1386 in pain after third molar extraction.
The effects of a TRPV1 antagonist (AZD1386) were investigated in patients with acute pain. After removal of a mandibular third molar and at request of analgesia 103 patients randomly received 95 mg AZD1386 (n = 40), placebo (n = 40) or 500 mg naproxen (n = 23) in a double-blind manner. Plasma samples were drawn, and pain intensity and body temperature were measured during 8 h after drug administration. ⋯ Adverse events were similar to placebo with the exception of 2 patients reporting chills. The highest individual body temperature after AZD1386 was 38.1°C, recorded in 2 patients. In summary, AZD1386 was well tolerated with a rapid analgesia that was short lasting despite sustained plasma concentration.
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Perception of emotional stimuli alters the perception of pain. Although facial expressions are powerful emotional cues - the expression of pain especially plays a crucial role for the experience and communication of pain - research on their influence on pain perception is scarce. In addition, the opposite effect of pain on the processing of emotion has been elucidated even less. ⋯ Most important, painful thermal stimuli increased the arousal of simultaneously presented pain expressions, and in turn, pain expressions resulted in higher pain ratings compared to all other facial expressions. These findings demonstrate that the modulation of pain and emotion is bidirectional with pain faces being mostly prone to having mutual influences, and support the view of interconnections between pain and emotion. Furthermore, the special relevance of pain faces for the processing of pain was demonstrated.
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Although previous research has examined the relationships between caregiver proximal soothing and infant pain, there is a paucity of work taking infant age into account, despite the steep developmental trajectory that occurs across the infancy period. Moreover, no studies have differentially examined the relationships between caregiver proximal soothing and initial infant pain reactivity and pain regulation. This study examined how much variance in pain reactivity and pain regulation was accounted for by caregiver proximal soothing at 4 routine immunizations (2, 4, 6, and 12 months) across the first year of life, controlling for preneedle distress. ⋯ Preneedle distress and pain reactivity accounted for the largest amount of variance in pain regulation, with this increasing after 2 months. It was concluded that within each immunization appointment across the first year of life, earlier infant pain behaviour is a stronger predictor of subsequent infant pain behaviour than caregiver proximal soothing. Given the longer-term benefits that have been demonstrated for proximal soothing during distressing contexts, caregivers are still encouraged to use proximal soothing during infant immunizations.
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Bradykinin (BK) is an inflammatory mediator that can evoke oedema and vasodilatation, and is a potent algogen signalling via the B1 and B2 G-protein coupled receptors. In naïve skin, BK is effective via constitutively expressed B2 receptors (B2R), while B1 receptors (B1R) are purported to be upregulated by inflammation. The aim of this investigation was to optimise BK delivery to investigate the algesic effects of BK and how these are modulated by inflammation. ⋯ We have optimised a versatile experimental model by which BK and its analogues can be administered to human skin. We have found that there is an early phase of BK-induced pain which partly depends on the release of inflammatory mediators by MCs; however, subsequent hyperalgesia is not dependent on MC degranulation. In naïve skin, B2R signaling predominates, however, cutaneous inflammation results in enhanced B1R responses.