Articles: hyperalgesia.
-
Randomized Controlled Trial
Temporal summation of pressure pain during muscle hyperalgesia evoked by nerve growth factor and eccentric contractions.
Nerve growth factor (NGF) has a key role in the generation and potentiation of pain. Its centrally sensitizing effects may facilitate pain responses to noxious stimulus. This study assessed (1) the influence of NGF on delayed onset muscle soreness (DOMS) in shoulder muscles; and (2) the temporal summation of pressure pain during hyperalgesia induced by NGF and DOMS. ⋯ The NGF injected side had higher pain ratings during temporal summation at 1s ISI compared with the contralateral side 24h after injections. Intramuscular administration of NGF intensified the DOMS responses, evoking facilitated temporal summation. Central as well as peripheral sensitization mechanisms may play a role in the facilitation.
-
Basic Clin. Pharmacol. Toxicol. · Aug 2009
Randomized Controlled TrialEvoked human oesophageal hyperalgesia: a potential tool for analgesic evaluation?
Hypersensitivity is a common finding in visceral disorders. Therefore, in the development and testing of analgesics for the treatment of visceral pain, it is important to establish an experimental pain model of visceral hypersensitivity. Such a model will mimic the clinical situation to a higher degree than pain models where the receptors and peripheral afferents are briefly activated as with, for example, electrical, thermal, and mechanical stimulations. ⋯ Acid+capsaicin perfusion induced 56% reduction of the pain threshold to heat (P = 0.04), 19% reduction of the pain threshold to electrical stimuli (P < 0.001), 78% increase of the referred pain areas to mechanical stimulation (P < 0.001) and 52% increase of the referred pain areas to electrical stimulus (P = 0.045). All volunteers were sensitised to one or more modalities by acid+capsaicin. The model was able to evoke consistent hyperalgesia and may be useful in future pharmacological studies.
-
Randomized Controlled Trial
The effect of local anaesthetic on age-related capsaicin-induced mechanical hyperalgesia--a randomised, controlled study.
Adults over 65 years exhibit a prolonged punctate hyperalgesia induced by topical application of capsaicin. The aim of this study was to investigate the role of peripheral afferent input in the slowed resolution of punctate hyperalgesia in older people. Twenty young (25.7+/-4.8 years) and 19 old (74.9+/-4.4 years) healthy adults were recruited, and subjects in each age group were randomly assigned to receive either EMLA cream (a local anaesthetic) (n=10 in each age group) or Sorbolene treatment (n=9 in the older group, n=10 in the young group) after the development of punctate hyperalgesia. ⋯ Stoicism and cautiousness measured with Pain Attitude Questionnaire were negatively correlated with highest pain rating in the young, but not in the older groups. We suggest that the prolonged punctate hyperalgesia in older adults is possibly sustained by central mechanisms, indicating age differences in central plasticity following acute injury. The relationship between such age-related changes and the chronicity of pain in older adults should be further explored.
-
Randomized Controlled Trial
Medial prefrontal cortex activity is predictive for hyperalgesia and pharmacological antihyperalgesia.
Sodium channel blockers are known for reducing pain and hyperalgesia. In the present study we investigated changes in cerebral processing of secondary mechanical hyperalgesia induced by pharmacological modulation with systemic lidocaine. An experimental electrical pain model was used in combination with functional magnetic resonance imaging. ⋯ However, only activity in mPFC was inversely correlated to area of hyperalgesia during placebo and antihyperalgesic treatment effect. Furthermore, the difference of mPFC activity during hyperalgesia and placebo versus hyperalgesia and lidocaine correlated inversely with the change of the weighted hyperalgesic area (as a factor of area and rated pain intensity). We conclude that activity in mPFC correlates inversely with individual extent of central hyperalgesia and predicts individual pharmacological antihyperalgesic treatment response.
-
Randomized Controlled Trial
[Modulation of cortical pain processing by cyclooxygenase inhibition: a functional MRI study].
Little is known about changes in brain activity with pharmacological modulation of hyperalgesia. Therefore, we sought to investigate the cerebral processing of hyperalgesia and acute pain using functional magnetic resonance imaging (fMRI) and pharmacological modulation with cyclooxygenase (COX) inhibitors. ⋯ This study provides new evidence for the involvement of COX inhibitors in modulating the cerebral activity associated with acute pain and hyperalgesia. Our results hint at a differential modulation of brain areas under either analgesia or antihyperalgesia.