Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In mice X-irradiated with doses of 200 R and 400 R, there was a substantial increase in spleen adenyl cyclase activity; there was similar activation by MEA. In mice given MEA before irradiation, an additive effect of radiation and the radioprotective drug was observed. On the other hand, a dose of 800 R given either alone or after pre-treatment with MEA failed to elicit any change in cyclase activity. The results indicate the importance of the adenyl cyclase system in the response of cells to irradiation and action of MEA.
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PMID:Effects of ionizing radiation and cysteamine (MEA) on activity of mouse spleen adenyl cyclase. 108 63

The properties of brain capillary endothelial cells (BCECs) have been analyzed. BCECs express two types of receptor sites for endothelins (ETs), and ETA-like receptor, and an ETB-like receptor that is not coupled to phospholipase C but whose occupancy activates Na+/H+ exchange activity. The ETA receptor is positively coupled to phospholipase C and negatively coupled to adenylate cyclase. BCECs, unlike aortic endothelial cells, express high-affinity receptor sites for C-type natriuretic peptide. They respond to exogenous nitric oxide (NO) and to NO donor molecules by large activations of soluble guanylate cyclase. They produce little cGMP in response to A23187 or to agonists of phospholipase C but do so after an exposure to interleukin-1. The physiological consequence of the high reactivity of BCECs to vasoactive factors is discussed.
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PMID:Function of vasoactive factors in the cerebral microcirculation. 128 98

We examined the intracellular signal transduction of two endothelin receptor subtypes (ETA and ETB) by transfection and stable expression of individual receptor cDNAs in Chinese hamster ovary cells. Both receptors showed a rapid and marked stimulation of phosphatidylinositol hydrolysis and arachidonic acid release in response to agonist interaction. The two receptors, however, exhibited different responses in the cyclic AMP transduction cascades. ETA mediated the accumulation of cyclic AMP formation, whereas ETB displayed an inhibitory action on the forskolin-stimulated cyclic AMP accumulation. In both receptors, the responses of phosphatidylinositol hydrolysis, arachidonic acid release, and cyclic AMP formation were induced in complete agreement with the endothelin-binding selectivity of each receptor subtype. Endothelin, added together with GTP, activated the adenylate cyclase activity in membrane preparations of ETA-expressing cells, indicating the direct linkage of ETA to the adenylate cyclase system. Pertussis toxin treatment of ETA-expressing cells resulted in partial inhibition of the endothelin-induced cyclic AMP accumulation, whereas the same treatment of ETB-expressing cells completely abolished the endothelin-induced inhibition of cyclic AMP formation. Thus, the two endothelin receptor subtypes are coupled to multiple but distinct signal transduction cascades through different G proteins.
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PMID:Coupling of two endothelin receptor subtypes to differing signal transduction in transfected Chinese hamster ovary cells. 131 97

The action of endothelins (Et) on cAMP formation was studied in endothelial cells from rat brain microvessels. Et-1 and Et-3 had no action by themselves. They both inhibited cholera toxin stimulated adenylate cyclase by about 50%. K0.5 values were observed at 2 nM and 40 nM for Et-1 and Et-3 respectively, indicating an involvement of a low affinity Et-3 receptor. Coupling to adenylate cyclase was achieved by a pertussis toxin sensitive mechanism. Another action of endothelins in brain capillary endothelial cells was to stimulate phospholipase C. This action involved a low affinity Et-3 receptor and a pertussis toxin insensitive mechanism. It is concluded that in brain capillary endothelial cells, ETA like receptors are coupled to phospholipase C and to adenylate cyclase via two different mechanisms.
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PMID:Endothelins inhibit adenylate cyclase in brain capillary endothelial cells. 165 65

1. Detection of ET-LI in porcine and human tissues in the present study revealed the presence of high levels in blood vessels, heart, airways, kidney, placenta, amnion and umbilical vessels. ET-1 was the predominant form in both porcine and human tissues, while evidence for additional occurrence of ET-3 was obtained in the porcine kidney and spinal cord. No evidence for presence of VIC or ET-2 was obtained in the studied porcine or human tissues. Immunohistochemical techniques revealed the presence of ET-LI in the amniotic membrane cells as well as in vascular endothelial cells. 2. Transient release of ET-LI from the porcine spleen was observed during endotoxin infusion and after a 2 min period of asphyxia. During endotoxin administration plasma ET-LI increased progressively and the presence of both ET-1 and big ET-1 in the plasma was shown. Short term sympatho-adrenal activation did not evoke ET-release, however. In man, high levels of ET-LI, indicating release, were observed in the amniotic fluid and umbilical plasma at birth. 3. Specific, high affinity ET receptors were demonstrated in human and porcine tissues. One main characteristic for ET binding was the extremely slow dissociation rate. The ET-1 selective ETA receptor was predominant in the porcine spleen and renal artery as well as in the human heart and umbilical arteries, whereas the ETB receptor predominated in the porcine renal medulla and the spinal cord and the human placenta. In the porcine and human lung a mixed population of ETA and ETB receptors seemed to be present. ET-1 but not ET-3 increased IP turnover in the spleen, while both ET-1 and ET-3 was effective in the lung, suggesting the same second messenger system for both receptor subtypes. Neither ET-1 nor ET-3 was observed to have any effect on the adenylate cyclase system. 4. ET-1 was extremely potent as a vasoconstrictor in the porcine kidney and spleen in vivo, while the effect in the femoral vascular bed was less pronounced. ET-3 was considerably less potent than ET-1 as vasoconstrictor in the kidney and the spleen. However, ET-1 and ET-3 acted equipotently as vasodilators in the bronchial circulation, suggesting opposite vascular effects in the different vascular beds. Big ET-1 caused only minor vasoconstriction. ET-1 was a potent constrictor agent of human coronary, pulmonary and umbilical vessels as well as of human bronchi in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Biochemical and functional characterization of endothelin peptides with special reference to vascular effects. 165 15

To study signal transduction pathways of endothelin (ET) in human heart, we assessed, in isolated human right atria, the effects of ET-1 and ET-3 on inositol phosphate (IP) formation and on the adenylate cyclase/cyclic AMP system. In right atrial slices, ET-1 (10(-10)-10(-6)M) concentration-dependently increased [3H]IP accumulation and decreased 10-microM isoprenaline-induced or 1-microM forskolin-induced increases in cyclic AMP content. ET-3 was approximately 100 times less potent. The cyclic AMP-decreasing effect of ET-1 (10(-11)-10(-6)M) could also be demonstrated directly in adenylate cyclase assays in right atrial membranes; again, ET-3 was approximately 100 times less potent. We conclude that in human right atrium, ETA receptors couple to two different signal-transduction pathways: IP formation and inhibition of adenylate cyclase.
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PMID:Endothelin ETA-receptors couple to inositol phosphate formation and inhibition of adenylate cyclase in human right atrium. 751 68

C-type natriuretic peptide and sodium nitroprusside, a nitric oxide donor molecule, induced large increases in cyclic GMP formation in cultured rat brain capillary endothelial cells. Isoproterenol, a potent agonist of adenylate cyclase, potentiated the actions of C-type natriuretic peptide and of sodium nitroprusside. These actions were not observed in the presence of isobutylmethylxanthine and were mimicked by forskolin. Endothelin-1 had no action on basal cyclic GMP levels. It reduced cyclic GMP formation induced by C-type natriuretic peptide and sodium nitroprusside by about 50%. These actions involved an ETA receptor subtype and a Ca(2+)-dependent and protein kinase C-independent mechanism. Finally, increasing cyclic GMP slightly prolonged intracellular Ca2+ transients induced by endothelin-1. The results suggest the presence of extensive cross talk among cyclic AMP, cyclic GMP, and Ca(2+)-dependent mechanisms in endothelial cells of brain microvessels. The relevance of the results to the regulation of the blood-brain barrier permeability is discussed.
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PMID:Cross talk among cyclic AMP, cyclic GMP, and Ca(2+)-dependent intracellular signalling mechanisms in brain capillary endothelial cells. 751 50

The steroidogenic activity of the Leydig cell is regulated by glycoprotein and peptide hormones with the potential to activate both adenylate cyclase and phospholipase C. Although the control of androgen production by LH is clearly mediated by cAMP, the extent to which Ca(2+)-mobilizing stimuli control Leydig cell function is less well defined. The basal level of intracellular calcium ([Ca2+]i) in adult rat Leydig cells was 70-160 nM and was unaffected by high K+ or the dihydropyridine calcium channel agonist, Bay K 8644. These findings are consistent with the absence of voltage-sensitive calcium channels in the Leydig cell. In addition, no increase in [Ca2+]i was observed in cells treated with LH, CRF, and serotonin. However, both GnRH and endothelin-1 (ET-1) induced rapid and transient elevations of [Ca2+]i that were not associated with a sustained plateau phase and were unaffected by removal of Ca2+ from the incubation medium. The amplitude of the [Ca2+]i response was not altered by increasing concentrations of GnRH and ET-1, but the number of responsive cells increased progressively to a maximum of about 30% of the Leydig cell population. The calcium-mobilizing actions of GnRH and ET-1 were abolished by the GnRH and ETA receptor antagonists, [Dp-Glu1,D-Phe2,D- Trp3,6]GnRH and BQ-123, respectively. The majority of the cells expressed solely GnRH or ETA receptors, and about 10% expressed both receptors. GnRH-induced Ca2+ responses were observed almost exclusively in medium-sized Leydig cells, whereas ET-induced responses were most frequent in large Leydig cells. These data demonstrate that single Leydig cells expressing GnRH and ETA receptors exhibit monophasic [Ca2+]i responses that are activated in an all-or-none fashion. Such transient Ca2+ signaling may trigger short term cellular responses or could modulate the actions of gonadotropins acting through the cAMP signaling pathway.
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PMID:Calcium signaling in single rat Leydig cells. 762 78

We have studied whether endothelin (ET) isopeptides have any effects on adenylate cyclase activity via different guanyl nucleotide-binding proteins (G-proteins) in cultured rat vascular smooth muscle cells (VSMC) and bovine endothelial cells (EC). Northern blot analysis clearly demonstrated gene expression of ETA receptors in VSMC and ETB receptors in EC. ET-1 dose-dependently (10(-9)-10(-6) M) stimulated cAMP formation in VSMC, whose effect was inhibited completely by ETA receptor antagonist (BQ-123) but not by indomethacin or quinacrine. The ET-1-induced cAMP formation was additive with isoproterenol but not with cholera toxin. In contrast, ET-3 and ETB receptor agonist (BQ-3020) dose-dependently (10(-9)-10(-6) M) inhibited forskolin-stimulated cAMP formation in EC, whose effect was completely abolished by pertussis toxin. Cholera toxin ADP ribosylated 45- and 52-kilodalton proteins in VSMC, whereas pertussis toxin ADP ribosylated the 41-kilodalton protein in EC. These data suggest that, in addition to phospholipase C via Gq, ETA and ETB receptor subtypes are functionally coupled to adenylate cyclase, possibly via Gs in VSMC and Gi in EC, respectively.
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PMID:Endothelin receptor subtypes are coupled to adenylate cyclase via different guanyl nucleotide-binding proteins in vasculature. 767 93

In the mammalian iris sphincter smooth muscle, endothelins (ET) activate both adenylate cyclase and the polyphosphoinositide cascade, and the levels of cyclic AMP (cAMP) and inositol 1,4,5-trisphosphate (IP3) produced are species specific. Radioligand binding studies, using [125I]ET-1 and [125I]ET-3 and determination of changes in cAMP, IP3 and contraction due to the peptides revealed the existence of ETA and ETB receptor subtypes in this tissue. In rabbit sphincter, ETA receptors constitute about 80% of total ET receptor population and these are coupled to IP3 production and contraction. In bovine sphincter, ETB receptors constitute about 72% of the total ET receptors and these are coupled to cAMP formation. Thus, in rabbit sphincter: 1) ET-1 and ET-2, two potent ETA receptor agonists, induced IP3 production and contraction at a much higher rate than ET-3, a weak ETA agonist. The EC50 for contraction by ET-1, ET-2 and ET-3 were 40, 45 and 300 nM, respectively. 2) Sarafotoxin-S6c (SRTX-c), a selective ETB receptor agonist, had no effect on IP3 and contraction in this tissue. 3) D-Asp-L-Pro-D-Val-L-Leu-D-Trp (BQ-123), a selective ETA receptor antagonist, inhibited the above responses to ET. 4) ET and SRTX-c induced cAMP formation at a much lower rate than that of IP3 and contraction. In contrast, in the bovine sphincter: 1) ET and SRTX-c induced cAMP formation in a dose-dependent manner, the order of potency being SRTX-c > ET-3 congruent to ET-2 congruent to ET-1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of iris sphincter smooth muscle endothelin receptor subtypes which are coupled to cyclic AMP formation and polyphosphoinositide hydrolysis. 813 49


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