Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.2 (guanylate cyclase)
 8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endotoxin includes an enzyme that synthesizes nitric oxide (NO) from l-arginine (NO synthase) in vascular smooth muscles cells, macrophages, and fibroblasts, leading to the release of NO. We evaluated the release of NO and its intracellular action on the Ca2+-activated K+ channel (KCa channel) in cultured human dermal papilla cells by use of the electron paramagnetic response (EPR) spin trapping method and the patch clamp technique. In dermal papilla cells pretreated for 24 h with endotoxin (1 microgram/microliter), application of 1 microM L-arginine generated NO, although no measurable release of NO was observed in cells without endotoxin pretreatment, as determined by the EPR spin trapping method. With the patch clamp technique, we found that the KCa channel of dermal papilla cells had high conductance and was voltage dependent. In addition, after endotoxin pretreatment, the extracellular application of 100 microM l-arginine modulated the KCa channel in the cell-attached patch configurations. In inside-out patch configuration, however, NO produced by L-arginine itself did not modulate the Kca channel. The modulation of the KCa channel was suppressed by pretreatment with 100 microM N omega-nitro-L arginine methyl ester, and inhibitor of inducible and constitutive NO synthases. Methylene blue, a blocker of guanylate cyclase, inhibited the L-arginine-induced activation of the Kca channel. Theses results indicate that the endotoxin-induced L-arginine pathway cell generates No, which consequently modulated the KCa channel in cultured human dermal papilla cells by increasing of cyclic GMP-dependent phosphorylation.
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PMID:Endotoxin-induced L-arginine pathway produces nitric oxide and modulates the Ca2+-activated K+ channel in cultured human dermal papilla cells. 860 38

1. In rat aortic rings precontracted by phenylephrine, H7 (10(-5)M) and staurosporine (10(-7)M), which inhibit PKA, PKG and PKC, and H-89 (10(-6)M), which inhibits PKA and PKG, potentiated relaxations induced by nitroglycerin. Forskolin-induced relaxations were not affected by H7 (10(-5)M). 2. Nitroglycerin-induced relaxations were not affected by calphostin-C (10(-7)M), which inhibits PKC, H-89 (10(-7)M), which inhibits PKA, and staurosporine (2 x 10(-9)M), which inhibits PKC. 3. Iberiotoxin (3 x 10(-8)M), an inhibitor of large conductance Kca channels, partly inhibited the relaxation induced by nitroglycerin and completely inhibited the potentiating effect of H7 on nitroglycerin-induced relaxations. 4. The potentiating effect of zaprinast (10(-5)M), an inhibitor of cGMP-phosphodiesterase, on nitroglycerin-induced relaxation was not affected by iberiotoxin. In the presence of methylene blue (10(-5)M), an inhibitor of guanylate cyclase, the residual relaxing response to nitroglycerin was not affected by H7, but it was inhibited by iberiotoxin. 5. These results suggest that the potentiation of nitroglycerin-induced relaxation by H7, staurosporine and H-89 may be due to inhibition of PKG.
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PMID:The potentiation of nitroglycerin-induced relaxation by PKG inhibition in rat aortic rings. 885 8

The aim of the present study was to analyze the mechanisms involved in the vasodilator responses elicited by nitric oxide (NO) in segments of porcine posterior descending coronary artery. Exogenous NO (0.1-30 microM) induced concentration-dependent relaxations in segments precontracted with a concentration of the thromboxane A2 mimetic, U-46619 (30-300 nM) that produced a contraction 70% (submaximal contraction) of that elicited by 75 mM K+ (maximal contraction). The relaxations were almost abolished by 6-anilinoquinoline-5,8-quinone (LY-83583, 10 microM), an inhibitor of guanylate cyclase, and with precontraction with 40 or 60 mM K+. Relaxations were reduced by 5 mM tetraethylammonium (TEA), a blocker of Ca(2+)-activated K+ channels (Kca channels) and unaltered by ouabain (500 microM), 4-aminopyridine (1 mM), glibenclamide (10 microM), apamin (1 microM) and charybdotoxin (0.3 microM), inhibitors of sodium pump, voltage-sensitive, ATP-sensitive, small-conductance Kca and large-conductance KcaK+ channels, respectively. These results suggest that the relaxation caused by exogenous NO is mediated by guanylate cyclase activation, with only a slight participation of a hyperpolarizing mechanism mediated by activation of Kca channels.
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PMID:Mechanisms involved in relaxation induced by exogenous nitric oxide in pig coronary arteries. 1038 16

CORM-A1 is a newly described water-soluble carbon monoxide (CO) releasing molecule (CORM) that can deliver CO to various vascular beds in the absence of dramatic changes in blood carboxy-hemoglobin (COHb) levels. We tested the in vivo and in vitro renal vascular effects of CORM-A1 administration using anesthetized mice instrumented with a renal flow probe as well as in isolated, pressurized renal interlobar arteries. Administration of CORM-A1 (0.96 micromol) resulted in a significant increase in renal blood flow (RBF) of 33 +/- 6% as compared to control. Administration of acetylcholine (50 pmol) caused a similar increase in RBF (25 +/- 4%). In order to determine if the vasodilatory effect of CORM-A1 in vivo was mediated through activation of soluble guanylate cyclase (sGC), mice were pretreated with the sGC inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 1 nmolkg(-1)min(-1)) for 30min. Pretreatment with ODQ significantly reduced the CORM-A1 mediated increase in RBF to 9 +/- 5% of control. In isolated pressurized renal interlobar arteries, CORM-A1 caused dose dependent vasodilatation of phenylephrine constricted arteries. The CORM-A1 mediated vasodilatation was significantly attenuated by ODQ to similar levels as observed in vivo. Inhibition of calcium activated potassium channels (Kca) with iberiotoxin resulted in a complete blockade of the CORM-A1 mediated vasodilatation in pressurized renal interlobar arteries. We conclude that CO released from CORM-A1 causes an increase in RBF and a decrease in vascular resistance through activation of sGC and opening of Kca channels in the kidney of the mouse.
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PMID:Renal vascular responses to CORM-A1 in the mouse. 1652 42