Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inflammatory pain, characterized by a decrease in mechanical nociceptive threshold (hyperalgesia), arises through actions of inflammatory mediators, many of which sensitize primary afferent nociceptors via G-protein-coupled receptors. Two signaling pathways, one involving protein kinase A (PKA) and one involving the epsilon isozyme of protein kinase C (PKCepsilon), have been implicated in primary afferent nociceptor sensitization. Here we describe a third, independent pathway that involves activation of extracellular signal-regulated kinases (ERKs) 1 and 2. Epinephrine, which induces hyperalgesia by direct action at beta(2)-adrenergic receptors on primary afferent nociceptors, stimulated phosphorylation of ERK1/2 in cultured rat dorsal root ganglion cells. This was inhibited by a beta(2)-adrenergic receptor blocker and by an inhibitor of mitogen and extracellular signal-regulated kinase kinase (MEK), which phosphorylates and activates ERK1/2. Inhibitors of G(i/o)-proteins, Ras farnesyltransferases, and MEK decreased epinephrine-induced hyper-algesia. In a similar manner, phosphorylation of ERK1/2 was also decreased by these inhibitors. Local injection of dominant active MEK produced hyperalgesia that was unaffected by PKA or PKCepsilon inhibitors. Conversely, hyperalgesia produced by agents that activate PKA or PKCepsilon was unaffected by MEK inhibitors. We conclude that a Ras-MEK-ERK1/2 cascade acts independent of PKA or PKCepsilon as a novel signaling pathway for the production of inflammatory pain. This pathway may present a target for a new class of analgesic agents.
 ...
PMID:Nociceptor sensitization by extracellular signal-regulated kinases. 1151 80

Inflammatory pain, characterized by a decrease in the nociceptive threshold, arises through the actions of inflammatory mediators. Mitogen-activated protein kinase cascades participate in peripheral nociceptive sensitization. We examined the involvement of c-Jun N-terminal kinase (JNK) in the dorsal root ganglion (DRG) in the early phase of inflammation-induced hyperalgesia. An intra-plantar (i.pl.) injection of complete Freund's adjuvant induced the activation of JNK in DRG neurons within 30 min. Pre-treatment as well as post-treatment of rats with a JNK inhibitor, SP600125, significantly attenuated thermal hyperalgesia, as assessed by paw-withdrawal latency, and the upregulation of c-fos immunoreactivity in dorsal horn neurons. An i.pl. injection of nerve growth factor (NGF) also induced the phosphorylation of JNK as well as thermal hyperalgesia, and SP600125 improved hyperalgesia. Inhibitor experiments suggest that JNK and extracellular signal-regulated protein kinase act on primary nociceptive neurons synergistically. These findings demonstrate that JNK is a therapeutic target for treating inflammation-induced pain hypersensitivity.
 ...
PMID:c-Jun N-terminal kinase activation in dorsal root ganglion contributes to pain hypersensitivity. 1605 88

Previous experience of chronic pain causes enhanced responses to upcoming noxious events in both humans and animals, but the underlying mechanisms remain unclear. In the present study, we found that rats with complete Freund's adjuvant (CFA)-induced chronic inflammatory pain experience exhibited aggravated pain responses to later formalin test. Enhanced neuronal activation upon formalin assaults and increased phosphorylated cAMP-response element binding protein (CREB) were observed in the prelimbic cortex (PL) of rats with chronic inflammatory pain experience, and inhibiting PL neuronal activities reversed the aggravated pain. Inflammatory pain experience induced persistent p38 mitogen-activated protein kinase (MAPK; p38) but not extracellular regulated protein kinase (ERK) or c-Jun N-terminal kinase (JNK) hyperphosphorylation in the PL. Inhibiting the p38 phosphorylation in PL reversed the aggravated nociceptive responses to formalin test and down-regulated enhanced phosphorylated CREB in the PL. Chemogenetics identified PL-periaqueductal gray (PAG) but not PL-nucleus accumbens (NAc) as a key pathway in inducing the aggravated formalin pain. Our results demonstrate that persistent hyperphosphorylation of p38 in the PL underlies aggravated nociceptive responses in rats with chronic inflammatory pain experience.
 ...
PMID:Hypersensitivity of Prelimbic Cortex Neurons Contributes to Aggravated Nociceptive Responses in Rats With Experience of Chronic Inflammatory Pain. 2962 29