Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism by which stimulated polymorphonuclear leukocytes and neutrophils (PMNs) damage pulmonary vascular endothelium was investigated. The authors assessed the ability of unstimulated and mechanically stimulated PMNs to adhere to pulmonary endothelial cells and, thereby, alter pulmonary vascular permeability, measured as the pulmonary filtration coefficient (K) and haemodynamics. PMNs were stimulated by gentle agitation in a glass vial for 10 s. Perfusing lungs with the stimulated PMNs (n=6) resulted in significant accumulation of PMNs within the lungs, assessed by myeloperoxidase levels, and elicited a 4-fold increase in K and a 2-fold increase in pulmonary vascular resistance as compared to lungs perfused with unstimulated cells (n=6). The increases in K were completely blocked by GF109203X, a protein kinase C inhibitor (n=6); however, GF109203X only partially attenuated the increase in vascular resistance and had little effect on the accumulation of stimulated PMNs. An agonist of protein kinase C, phorbol myristate acetate, elicited dose dependent increases in both K and pulmonary vascular resistance even in the absence of PMNs (n=6). These findings indicate that the increases in pulmonary filtration coefficient and pulmonary vascular resistance induced by polymorphonuclear neutrophils result from endothelial cell injury mediated by activation of protein kinase C within the endothelial cells themselves.
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PMID:Endothelial signal transduction system enhances neutrophil-induced pulmonary vascular permeability. 1075 36

The opioid receptor antagonist naltrexone, which is used in detoxification and rehabilitation programmes in opioid addicts, can precipitate opioid withdrawal symptoms even in patients who have no opioid present. We tested the hypothesis that in order to precipitate withdrawal, opioids need to convert the inactive opioid receptor site via protein kinase C into a constitutively active form on which the antagonist precipitates withdrawal. Acute microg/kg), given for 6 days, which was followed by the antagonist naltrexone (20 microg/kg i.v.) in the awake trained canine (n = 10). Abrupt displacement of opioid binding resulted in acute withdrawal symptoms: increase in blood pressure, heart rate, increase in amplitude height of somatosensory evoked potential, reduced tolerance to colon distention and a significant increase in grading of vegetative variables (restlessness, panting, thrashing of the head, whining, yawning, gnawing, salivation and/or rhinorrhoea, mydriasis, stepping of extremities and vomiting). Following a washout period of 14 days, the same animals were given the highly specific protein kinase C inhibitor H7 (250 microg/kg) prior to the same dosages of sufentanil and naltrexone. Such pretreatment was able to either attenuate or completely abolish the acute withdrawal symptoms. The data suggest that for precipitation of withdrawal, intracellular phosphorylation is a prerequisite in order to activate the opioid mu-receptor. In such a setting, naltrexone acts like an 'inverse agonist' relative to the action of the antagonist on a non-preoccupied receptor site not being exposed previously to a potent opioid agonist.
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PMID:Constitutive opioid receptor activation: a prerequisite mechanism involved in acute opioid withdrawal. 1619 64