introduction: the activity of hypothalamus-pituitary-adrenal (hpa) axis is increased following inflammation due to its closed relation with immune system. this axis indicates an increased secretion of acth, and corticosterone during acute inflammation while little is known about its activity during chronic inflammation such as rheumatoid arthritis (ra). in this study we measured the products of...

BACKGROUND Masticatory muscle pain may occur following immediate occlusal alteration by dental treatment. The underlying mechanisms are poorly understood. Transient receptor potential vanilloid-1 (TRPV1) and acid-sensing ion channel-3 (ASIC3) mediate muscle hyperalgesia under various pathologic conditions. We have developed a rat model of experimental occlusal interference (EOI) that consistent...

Descending controls of spinal nociceptive processing play a critical role in the development of inflammatory hyperalgesia. Acute peripheral nociceptor sensitization drives spinal sensitization and activates spino-supraspinal-spinal loops leading to descending inhibitory and facilitatory controls of spinal neuronal activity that further modify the extent and degree of the pain state. The afferen...

It is well established that dorsal root ganglion (DRG) cells synthesize prostaglandin. However, the role that prostaglandin plays in the inflammatory hyperalgesia of peripheral tissue has not been established. Recently, we have successfully established a technique to inject drugs (3 μL) directly into the L5-DRG of rats, allowing in vivo identification of the role that DRG cell-derived COX-1 and...

High voltage calcium channels are implicated in nociceptive transmission after nerve injury, capsaicin or formalin injection. The purpose of this study was to investigate the role of calcium channels in secondary heat hyperalgesia associated with acute joint inflammation. After induction of acute inflammation (knee joint injection of kaolin and carrageenan), decreased paw withdrawal latency (PW...

objective(s):neuropathic pain is caused by lesions or diseases affecting the somatosensory system and often responds poorly to typical medications.  in this study, we evaluated anti-nociceptive effects of morphine, gabapentin and their combination on heat hyperalgesia, cold and mechanical allodynia in chronic constriction injury (cci) model of neuropathic pain in rats. materials and methods: mo...

Repeated intramuscular acid injections produce long-lasting mechanical hyperalgesia that depends on activation of ASICs. The present study investigated if pH-activated currents in sensory neurons innervating muscle were altered in response to repeated acid injections, and if blockade of ASICs reverses existing hyperalgesia. In muscle sensory neurons, the mean acid-evoked current amplitudes and ...

Mechanical hyperalgesia is a common and potentially disabling complication of many inflammatory and neuropathic conditions. Activation of the enzyme PKCε in primary afferent nociceptors is a major mechanism that underlies mechanical hyperalgesia, but the PKCε substrates involved downstream are not known. Here, we report that in a proteomic screen we identified the NaV1.8 sodium channel, which i...

Inflammation and trauma lead to enhanced pain sensitivity (hyperalgesia), which is in part due to altered sensory processing in the spinal cord. The synaptic hypothesis of hyperalgesia, which postulates that hyperalgesia is induced by the activity-dependent long-term potentiation (LTP) in the spinal cord, has been challenged, because in previous studies of pain pathways, LTP was experimentally ...