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)

Incubation of rat peritoneal mast cells with substance P resulted in the transient stimulation of phosphoinositol breakdown and histamine secretion through an exocytotic process. These effects were inhibited markedly by a prior 2-hr exposure of the cells to pertussis toxin. Pertussis toxin also inhibited exocytosis induced by substance P, mastoparan and compound 48/80, but did not modify the secretory effect of the ionophore A23187. The transfer of rat peritoneal mast cells from balanced salt solution to calcium-free buffer led to a similar time-dependent decrease in their response to substance P and mastoparan. The concomitant absence of potassium from the calcium-free buffer enabled the mast cells to retain their secretory response. These data demonstrate identical dependency for calcium and monovalent ions of the secretory process elicited by substance P, mastoparan and compound 48/80. Pretreatment of mast cells with neuraminidase decreased the secretagogic effect of substance P, mastoparan and compound 48/80 without modifying the efficiency of the ionophore A23187. Thus, sialic acid residues might be involved in the initial binding of peptides and compound 48/80 to mast cells, which activate a pertussis toxin-sensitive G-protein and allows the increase in phospholipase C activity to induce exocytosis. This sequence of events might characterize the physiological pathway of mast cell activation by peptides, without necessarily requiring selective membrane receptors.
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PMID:Activation of rat peritoneal mast cells by substance P and mastoparan. 247 89

Schwann cells play an important role in both the development and regeneration of peripheral nerves. Proliferation and differentiation of Schwann cells are critically dependent on changes in the levels of cAMP. ATP is a fast excitatory transmitter in the peripheral nervous system, inducing depolarization of the vagus nerve through occupancy of P2-purinergic receptors. In the present study we demonstrate that extracellular ATP stimulates phospholipase C and inhibits adenylate cyclase activities in cultured Schwann cells. Addition of ATP inhibited, in a concentration-dependent manner, forskolin- or isoprenaline-stimulated adenylate cyclase activity. The rank order of potency corresponding to different purinergic receptor agonists was 2-methylthio-ATP > ATP = ADP > or = adenosine 5'-[gamma-thio]triphosphate (ATP[S]) > UTP, consistent with the involvement of a P2y subtype. Adenosine and adenosine 5'-[alpha,beta-methylene]-triphosphate (pp[CH2pA) were ineffective. Preincubation with pertussis toxin completely blocked this inhibitory effect. When Schwann cells were pre-labelled with myo-[3H]inositol and incubated in Hanks' balanced salt solution containing Ca2+ and Mg2+, addition of ATP[S] resulted in a concentration-dependent increase in the release of InsP with a concomitant increase in intracellular free [Ca2+] ([Ca2+]i). Under these conditions, the effects of both ATP and UTP were of lower magnitude. Removal of Ca2+ and Mg2+ from the assay medium resulted in a significant increase in the effects of ATP[S], ATP and UTP. The decreased response observed in the presence of both bivalent cations (1.2 mM Ca2+ and 1 mM Mg2+) could not be explained either by increased degradation of ATP by Ca2+/Mg2+-dependent nucleotidases or by cation influx. The rank order of potency for the effects of agonists on phospholipase C activity was ATP[S] = adenosine 5'[gamma-imido]triphosphate > ATP -UTP > ADP, indicating the involvement of a P(2U) receptor subtype in this response. Adenosine, AMP and pp[CH2]pA were ineffective. These results demonstrate that immortalized Schwann cells express P(2U) and P(2Y) purinoceptors, which are coupled to stimulation of phospholipase C and inhibition of adenylate cyclase, respectively. Our observations unveil signal-transduction pathways that may be used by ATP to regulate proliferation and differentiation of Schwann cells, and ultimately to influence nerve homeostasis.
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PMID:P2-purigenic receptors regulate phospholipase C and adenylate cyclase activities in immortalized Schwann cells. 867 70

Cultured pituicytes (neurohypophysial astrocytes) are normally flat amorphous cells when incubated (90 min) in a HEPES balanced salt solution (HBSS) but become stellate when incubated in HBSS supplemented with forskolin. This stellation process is attenuated by serum (0.5% vol/vol). The experiments described here were designed to determine whether serum attenuates stellation by modulation of the intracellular cyclic adenosine monophosphate (cAMP) concentration or some other mechanism. It was observed that the effect of serum on forskolin-induced stellation was not affected by pertussis toxin (100 ng/ml) and that serum also inhibited stellation induced by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX; 100 microM). Further, serum inhibited stellation induced by the membrane permeable cAMP analog 8-bromo cAMP (150 microM). These results indicate that although an increase of intracellular cAMP concentration is necessary for pituicyte stellation, an increase of intracellular cAMP concentration may be decoupled from stellation.
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PMID:Serum uncouples elevation of cyclic adenosine monophosphate concentration from cyclic adenosine monophosphate dependent morphological changes exhibited by cultured pituicytes. 915 37