cyclic-gmp and isoliquiritigenin

Chronic kidney disease (CKD) is a growing fatal health problem worldwide associated with vascular calcification. Therapeutic approaches are limited with higher costs and poor outcomes. Adenine supplementation is one of the most relevant CKD models to human. Insufficient Nitric Oxide (NO)/ cyclic Guanosine Monophosphate (cGMP) signaling plays a key role in rapid development of renal fibrosis. Natural products display proven protection against CKD. Current study therefore explored isoliquiritigenin, a bioflavonoid extracted from licorice roots, potential as a natural activator for soluble Guanylate Cyclase (sGC) in a CKD rat model.. 60 male Wistar rats were grouped into Control group (n = 10) and the remaining rats received adenine (200 mg/kg, p.o) for 2 wk to induce CKD. They were equally sub-grouped into: Adenine untreated group and 4 groups orally treated by isoliquiritigenin low or high dose (20 or 40 mg/kg) with/without a selective sGC inhibitor, ODQ (1-H(1,2,4)oxadiazolo(4,3-a)-quinoxalin-1-one, 2 mg/kg, i.p) for 8 wk.. Long-term treatment with isoliquiritigenin dose-dependently and effectively amended adenine-induced chronic renal and endothelial dysfunction. It not only alleviated renal fibrosis and apoptosis markers but also aortic calcification. Additionally, this chalcone neutralized renal inflammatory response and oxidative stress. Isoliquiritigenin beneficial effects were associated with up-regulation of serum NO, renal and aortic sGC, cGMP and its dependent protein kinase (PKG). However, co-treatment with ODQ antagonized isoliquiritigenin therapeutic impact.. Isoliquiritigenin seems to exert protective effects against CKD and vascular calcification by activating sGC, increasing cGMP and its downstream PKG.

Topics: Animals; Chalcones; Cyclic GMP; Fibrosis; Guanylate Cyclase; Humans; Kidney Failure, Chronic; Male; Nitric Oxide; Rats; Rats, Wistar; Renal Insufficiency, Chronic; Soluble Guanylyl Cyclase

The purpose of the present study is to investigate the effect of isoliquiritigenin (ISL) on the cerebral basilar artery in spontaneously hypertensive rats (SHR). The change of SHR systolic pressure was measured by tail artery pressure measurement instrument before and after ISL intervention. After perfusion with 1 × 10(-5) mol/L phenylephrine (PE), 1 × 10(-5) mol/L PE + 1 × 10(-4) mol/L ISL and 1 × 10(-5) mol/L PE, the diameter of the cerebral basilar artery separated from SHR was measured by pressure myograph. The current of large-conductance calcium-activated potassium (BKCa) channel of SHR single vascular smooth muscle cell (VSMC) was recorded by whole-cell patch-clamp technique and the cGMP levels of basilar artery was evaluated by ELISA. The results showed that 1) after intervention with ISL for 14 days, the systolic pressure of SHR was decreased from (218.3 ± 1.6) mmHg to (119.2 ± 1.9) mmHg (P < 0.01), but there was no difference in systolic pressure between ISL-treated SHR and Wistar-Kyoto (WKY) rat; 2) 1 × 10(-4) mol/L ISL relaxed the SHR cerebral basilar artery (P < 0.01); 3) ISL significantly increased the outward current density of VSMC from SHR cerebral basilar artery (P < 0.01, n = 6), and the effect could be reversed by 1 × 10(-3) mol/L TEA (a BKCa channel inhibitor), but 3 × 10(-4) mol/L 4-AP (a Kv channel inhibitor) had no effect on the enhanced current density induced by ISL in VSMC; 4) 1 × 10(-5) mol/L Methylene blue (a sGC inhibitor) significantly inhibited the ISL-enhanced current density in VSMC (P < 0.05, n = 6); 5) ISL significantly increased the cGMP level of SHR basilar artery (P < 0.05, n = 6). The results suggest that the role of the ISL in relaxing the SHR cerebral basilar artery may be related to its effect in enhancing BKCa current by increasing the levels of cGMP in the VSMC.

Topics: Animals; Basilar Artery; Blood Pressure; Cerebral Arteries; Chalcones; Cyclic GMP; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Patch-Clamp Techniques; Potassium Channels, Calcium-Activated; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Systole

Licorice root is used to treat asthma as a component of Shaoyao-Gancao-tang, a traditional Chinese medicine formula. In this study, we investigated the tracheal relaxation effects of isoliquiritigenin, a flavonoid isolated from the roots of Glycyrrhiza glabra (a kind of Licorice), on guinea-pig tracheal smooth muscle in vitro and in vivo. The tension changes of isolated tracheal rings were isometrically recorded on a polygraph. The large-conductance Ca2+-activated K+ channels (BKCa) were measured by inside-out patch-clamp techniques and intracellular Ca2+concentrations ([Ca2+]i) were tested by microfluorometric method in guinea-pig tracheal smooth muscle cells (TSMCs). Isoliquiritigenin produced concentration-dependent relaxation in isolated guinea-pig tracheal rings precontracted with acetylcholine, KCl, and histamine. Pretreatments with charybdotoxin, ODQ and KT5823 attenuated the relaxation induced by isoliquiritigenin. Isoliquiritigenin significantly increased intracellular cGMP level in cultured TSMCs and inhibited the activity of phosphodiesterase (PDE) 5 in human platelets. Moreover, isoliquiritigenin increased by 9-fold the probability of BKCa channel openings of TSMCs in inside-out patches and markedly reduced [Ca2+]i rise induced by acetylcholine inTSMCs, pretreatment with KT5823 attenuated above two responses to isoliquiritigenin. In vivo experiment isoliquiritigenin significantly prolonged the latency time of histamine-acetylcholine aerosol-induced collapse and inhibited the increase of lung overflow induced by intravenously administered histamine dose-dependently. These data indicate that isoliquiritigenin relaxes guinea-pig trachea through a multiple of intracellular actions, including sGC activation, inhibition of PDEs, and associated activation of the cGMP/PKG signaling cascade, leading to the opening of BKCa channels and [Ca2+]i decrease through PKG-dependent mechanism and thus to tracheal relaxation.

Topics: Animals; Calcium; Cells, Cultured; Chalcones; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Enzyme Inhibitors; Epithelium; Female; Glycyrrhiza; Guinea Pigs; In Vitro Techniques; Isometric Contraction; Male; Muscle Relaxation; Muscle, Smooth; Myocytes, Smooth Muscle; Nitric Oxide; Patch-Clamp Techniques; Phosphoric Diester Hydrolases; Plant Roots; Potassium Channels; Prostaglandins; Trachea

We have recently reported that mediation of intracerebellar nicotine-induced attenuation of cerebellar delta9-THC ataxia was via the alpha4beta2 nAChR. The present study was meant to investigate the role of cerebellar nitric oxide (NO)-guanylyl cyclase (GC) signaling in the alpha4beta2-mediated attenuation in CD-1 male mice. Drugs were given via intracerebellar microinfusion using stereotaxically implanted guide cannulas, with ataxia evaluated by Rotorod. Intracerebellar microinfusion of SNP (sodium nitroprusside, NO donor; 15, 30, 60 pg) and SMT (S-methylisothiourea, inhibitor of inducible NO synthase; 70, 140, 280 fg) significantly enhanced and reduced, respectively, intracerebellar RJR-2403 (selective alpha4beta2 agonist)-induced attenuation of delta9-THC ataxia dose-dependently. Intracerebellar isoliquiritigenin (GC-activator; 1, 2, 4 pg) and ODQ (1H[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one, GC inhibitor; 200, 400, 800 fg), significantly enhanced and reduced, respectively, intracerebellar RJR-2403-induced attenuation of delta9-THC ataxia dose-dependently. Further support for the role of NO was evidenced via increases in cerebellar NO(x) (nitrate+nitrite) levels following microinfusion of nicotine or RJR-2403 as compared to control, whereas delta9-THC significantly decreased NO(x) levels. "Nicotine/RJR-2403+delta9-THC" treated mice had cerebellar NO(x) levels significantly increased as compared to mice infused with delta9-THC alone. Results of the present investigation support the role of cerebellar NO-GC signaling in alpha4beta2 nAChR subtype-mediated attenuation of delta9-THC ataxia.

Topics: Animals; Area Under Curve; Cerebellar Ataxia; Cerebellum; Chalcones; Cyclic GMP; Dronabinol; Enzyme Inhibitors; Guanylate Cyclase; Male; Mice; Microinjections; Nicotine; Nicotinic Agonists; Nitric Oxide; Nitroprusside; Oxadiazoles; Postural Balance; Quinoxalines; Receptor, Cannabinoid, CB1; Receptors, Nicotinic; Stereotaxic Techniques

The effects of isoliquiritigenin on force of contraction (Fc), L-type Ca2+ current (I(Ca)) and intracellular Ca2+ concentration ([Ca2+]i) were investigated in rat ventricular heart muscle. Isoliquiritigenin increased Fc and I(Ca) and, after longer exposure times, resting tension and [Ca2+]i. The effect of isoliquiritigenin (100 microM) on I(Ca) was diminished by Rp-cAMPS (30 microM). 1H-[1,2,4]oxa- diazolo[4,3-a]quinoxalin-1-one (50 microM) did not influence the effects of isoliquiritigenin on Fc and I(Ca). The positive inotropic effects of isoprenaline and forskolin, but not of 3-isobutyl-1-methylxanthine, were potentiated by isoliquiritigenin (100 microM). In the presence of milrinone (10 microM), no further effects of isoliquiritigenin (100 microM) on Fc and I(Ca) were observed. It is suggested that the increase in Fc and I(Ca) by isoliquiritigenin is due to an accumulation of cyclic AMP. These effects are probably unrelated to an effect of the drug on soluble guanylyl cyclase, as reported for smooth muscle, but rather due to a direct inhibition of phosphodiesterase III activity.

Topics: Aldehyde Reductase; Animals; Calcium; Chalcone; Chalcones; Cyclic AMP-Dependent Protein Kinases; Cyclic GMP; Drug Interactions; Electrophysiology; Enzyme Inhibitors; Female; Guanylate Cyclase; Heart; In Vitro Techniques; Male; Membrane Potentials; Myocardial Contraction; Myocardium; Patch-Clamp Techniques; Plants, Medicinal; Rats; Rats, Sprague-Dawley

1. The vasorelaxant activity of isoliquiritigenin, isolated from Dalbergia odorifera T, was investigated in the phenylephrine-precontracted rat aorta by measuring tension, guanylate and adenylate cyclase activities, guanosine 3':5'-cyclic monophosphate (cyclic GMP) and adenosine 3':5'-cyclic monophosphate (cyclic AMP) levels. 2. Isoliquiritigenin concentration-dependently relaxed rat aorta contracted with phenylephrine, KCl, U-46619, endothelin and 5-hydroxytryptamine, with EC50s of 7.4 +/- 1.6, 10.5 +/- 2.3, 14.3 +/- 3.3, 11.8 +/- 2.0 and 13.6 +/- 3.7 microM, respectively. 3. Isoliquiritigenin caused endothelium-independent relaxation of phenylephrine-precontracted rat aortic rings. Neither NG-monomethyl-L-arginine (L-NMMA) (an inhibitor of the L-arginine-NO pathway) nor oxyhaemoglobin (which binds NO) modified the relaxant effect of isoliquiritigenin. The relaxant action of isoliquiritigenin also persisted in intact aorta in the presence of indomethacin or glibenclamide. However, methylene blue, an inhibitor of soluble guanylate cyclase, abolished relaxation induced by isoliquiritigenin. 4. Incubation of rat aorta with isoliquiritigenin not only increased aortic cyclic GMP content but also caused small increases in aortic cyclic AMP content, and greatly potentiated the increases in cyclic AMP observed in the presence of forskolin. The maximum increase in cyclic GMP by isoliquiritigenin was reached earlier than the increase in cyclic AMP. This result suggests that the increases in cyclic GMP caused by isoliquiritigenin might stimulate the accumulation of cyclic AMP. 5. Concentration-dependent increases in soluble guanylate cyclase activity were observed in isoliquiritigenin (1-100 microM)- or sodium nitroprusside (SNP)-treated rat aortic smooth muscle cells, while adenylate cyclase activity was unchanged in isoliquiritigenin (100 microM)-treated cells. 6. Relaxation and cyclic AMP formation of rat aorta caused by isoliquiritigenin was potentiated in the presence of forskolin (10 nM), which had little effect when given alone. 2',5'-Dideoxyadenosine (DDA,200 microM), an adenylate cyclase inhibitor, diminished the relaxation and cyclic AMP formation of rat aorta by isoliquiritigenin only in the presence of forskolin. DDA did not affect the increases in cyclic GMP formation induced by isoliquiritigenin. These results suggest that elevated levels of cyclic GMP may mediate the majority of the relaxation of the phenylephrine-precontracted aorta induced byisoliq

Topics: Aldehyde Reductase; Animals; Aorta; Chalcone; Chalcones; Cyclic AMP; Cyclic GMP; Dose-Response Relationship, Drug; Female; Guanylate Cyclase; Male; Methylene Blue; Muscle Relaxation; Muscle, Smooth, Vascular; Phenylephrine; Platelet Aggregation Inhibitors; Pyrrolidinones; Quinolones; Rats; Rats, Wistar; Rolipram

The effects of a stable prostacyclin analog, Iloprost, and aldose reductase inhibitors (ONO-2235 and isoliquiritigenin) were studied to elucidate the role of cAMP in diabetic neuropathy in relation to polyol metabolism. In in vivo experiments, the cAMP and myoinositol contents in sciatic nerves and motor nerve conduction velocity were significantly reduced in diabetic rats. Iloprost significantly restored the reduced cAMP content in sciatic nerves and improved motor nerve conduction velocity in diabetic rats. However, the contents of sorbitol or myoinositol in sciatic nerves were not affected by Iloprost in diabetic rats. On the other hand, aldose reductase inhibitors significantly reduced the sorbitol content and increased the cAMP and myoinositol contents in the sciatic nerves of diabetic rats. The motor nerve conduction velocity was also slightly but significantly improved by treatment with aldose reductase inhibitors. There was a negative correlation between cAMP and sorbitol in the sciatic nerves of diabetic rats treated with aldose reductase inhibitors and a positive correlation between cAMP and motor nerve conduction velocity. In in vitro experiments, Iloprost significantly increased cAMP, but did not affect the sorbitol content in sciatic nerves. Aldose reductase inhibitors inhibited sorbitol accumulation and increased cAMP in sciatic nerves. Our data suggest that polyol pathway activation somehow results in cAMP reduction in sciatic nerves and that the reduction of cAMP in peripheral nerves may be closely related to the pathogenesis of diabetic neuropathy.

Topics: Aldehyde Reductase; Animals; Blood Glucose; Chalcone; Chalcones; Cyclic AMP; Cyclic GMP; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Iloprost; Inositol; Male; Neural Conduction; Rats; Rats, Inbred WKY; Rhodanine; Sciatic Nerve; Sorbitol; Thiazolidines