Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracellular ATP secreted from stimulated nerves plays a role in neurotransmission. This study examined the effects of extracellular ATP on phospholipase A2 and C signalling pathways in rabbit astrocytes. ATP caused prostaglandin E2 (PGE2) generation and phosphoinositide hydrolysis in a time- and concentration-dependent manner. A P2y purinoceptor-selective agonist, 2-methylthio-ATP also caused phosphoinositide hydrolysis, but not PGE2 generation. A P2x purinoceptor-selective agonist, alpha, beta-methylene-ATP did not cause either phosphoinositide hydrolysis or PGE2 generation. Although pertussis toxin had no effect on 2-methylthio-ATP-induced phosphoinositide hydrolysis, it markedly decreased ATP-induced PGE2 generation, with significant inhibition of phosphoinositide hydrolysis. Dexamethasone and indomethacin which potently inhibited ATP-induced PGE2 generation, caused partial inhibition of phosphoinositide hydrolysis, suggesting that pertussis toxin-sensitive component of ATP-induced phospholipase C activation is mediated by cyclo-oxygenase metabolites of arachidonic acid. These results suggest that a stimulation of P2y receptor results in phospholipase C activation in a pertussis toxin-insensitive manner, and that a P2 receptor other than the P2y or P2x subtypes is involved in ATP-induced phospholipase A2 activation via a pertussis toxin-sensitive G protein.
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PMID:Effects of ATP on phosphoinositide hydrolysis and prostaglandin E2 generation in rabbit astrocytes. 917 88

The contractile effect of ATP given alone or in the presence of other nucleotides was studied in rat aortic strips. A sustained contraction in response to ATP (30 microM to 10 mM) was observed during UTP exposure instead of the fast transient contraction produced via P2x purinoceptor activation in the absence of UTP, and contrary to the relaxation elicited when the tone had been raised by noradrenaline and KCl. This sustained ATP effect was produced in the smooth muscle and not via the same mechanism through which UTP elicited contraction, since the contractions in response to UTP and ATP were additive. They were also coupled to different transduction pathways: the effect of UTP but not that of ATP was pertussis toxin-sensitive. In contrast to the fast transient ATP contraction during basal tone, the sustained response was not desensitized by alpha,beta-methylene ATP exposure (30 microM), but was inhibited by reactive blue 2 (10 and 30 microM). Among the nucleotides assayed, UDP and ATPgammaS also enabled ATP to elicit a sustained contraction. ADP, AMP, dATP, 2-methylthio ATP, alpha,beta-methylene ATP, GTP, GDP, GMP, CTP and ITP also induced a sustained contraction in the presence of UTP. However, adenosine (1 mM) and adenine (0.3 to 3 mM) induced relaxation when the tone had been raised by UTP. According to these results a non-selective nucleotide receptor, different from the P2 purinoceptors functionally characterized so far, seems to mediate sustained contractions in rat aortic strips in the presence of UTP, UDP or ATPgammaS.
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PMID:Pharmacological evidence for a receptor mediating sustained nucleotide-evoked contractions of rat aorta in the presence of UTP. 967 Nov 2