Articles: hyperalgesia.
-
Neuroscience letters · Jul 2010
Cyclooxygenase inhibitors suppress the expression of P2X(3) receptors in the DRG and attenuate hyperalgesia following chronic constriction injury in rats.
Recent evidence suggests that P2X(3) receptors express abundantly in nociceptive sensory neurons and play an important role in neuropathic pain. Upregulation of prostaglandin E2 (PGE2) after nerve injure is involved in the pathogenesis of neuropathic pain. An increase of P2X(3) receptors after chronic constriction injury (CCI) to the sciatic nerve has also been reported, the mechanisms are not known clearly. ⋯ The increase of P2X(3) receptors in the DRG in CCI rats on day 14 after surgery was also significantly inhibited; the effect of ibuprofen was stronger than that of celecoxib. These results demonstrate that up-regulated COX/PGE2 after nerve damage may play an important role in neuropathic pain. They are highly involved in the expression of P2X(3) receptors in the DRG in CCI rats.
-
Clinical studies demonstrate attenuation of trigeminal-related pain states such as migraine by intranasal CO(2) application. This study investigated the underlying mechanisms of this observation and its potential use to reverse trigeminal pain and hypersensitivity. ⋯ Our results indicate that intranasal CO(2) application results in a subsequent attenuation of trigeminal nociception, mediated by protonic activation of TRPV(1) and ASIC channels. A potential central mechanism for this attenuation is discussed. The antihyperalgesic effects of intranasal CO(2) application might be useful for the treatment of trigeminal pain states.
-
Activation of extracellular signal-regulated kinase-1/2 (ERK1/2) and its involvement in regulating gene expression in spinal dorsal horn, cortical and subcortical neurons by peripheral noxious stimulation contribute to pain hypersensitivity. Transcutaneous electrical nerve stimulation (TENS) is a treatment used in physiotherapy practice to promote analgesia in acute and chronic inflammatory conditions. In this study, a total number of 114 rats were used for three experiments. ⋯ TENS on Yongquan acupoint for 20 min produced obvious analgesic effects as demonstrated with increased HPL to thermal stimuli of CFA-treated rats. In addition, TENS application suppressed the CFA-induced ERK2 activation and c-Fos protein expression. These results suggest that down-regulation of ERK2 phosphorylation and c-Fos expression were involved in TENS inhibition on CFA-induced thermal hyperalgesia of rats.
-
Review
Opioids, pain, the brain, and hyperkatifeia: a framework for the rational use of opioids for pain.
Opioids have relieved more human suffering than any other medication, but their use is still fraught with significant concerns of misuse, abuse, and addiction. This theoretical article explores the hypothesis that opioid misuse in the context of pain management produces a hypersensitivity to emotional distress, termed hyperkatifeia. ⋯ Repeated engagement of opponent processes without time for the brain's emotional systems to reestablish homeostasis will further drive changes in emotional processes that may produce opioid abuse or addiction, particularly in individuals with genetic or environmental vulnerability.
-
Ultraviolet (UV) induced cutaneous inflammation is emerging as a model of pain with a novel sensory phenotype. A UVB dose of 1000mJ/cm2 produces a highly significant thermal and mechanical hypersensitivity. Here we examined the properties and mechanisms of such hyperalgesia in rats. ⋯ Notably alteration in mechanical responses of Adelta- and heat-insensitive C-nociceptors were particular to stronger stimuli. Spontaneous activity was not induced by this dose of UVB. We conclude that UVB-induced mechanical hyperalgesia may be explained by a net shift in peripheral nociceptor response properties.