scholarly journals GLP-1 Relaxes Rat Coronary Arteries by Enhancing ATP-Sensitive Potassium Channel Currents

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Qian-Feng Xiong ◽  
Shao-Hua Fan ◽  
Xue-Wen Li ◽  
Yu Niu ◽  
Jing Wang ◽  
...  
Keyword(s):  
Channel Blocker ◽  
Dependent Manner ◽  
Nitric Oxide Synthase Inhibitor ◽  
Relaxant Effect ◽  
Beneficial Effects ◽  
Thromboxane Receptor ◽  
New Type ◽  
Synthase Inhibitor ◽  
Oxide Synthase ◽  
Channel Currents

GLP-1 is a new type of antidiabetic agent that possesses many beneficial effects. Although its cardiovascular actions have been widely examined, little is known about GLP-1’s effects on the rat coronary artery (RCA) or about the mechanisms underpinning these effects. Here, we report that GLP-1 inhibits depolarization- or thromboxane receptor agonist (U46619)-induced RCA contraction in a dosage-dependent manner. Vasorelaxation was attenuated by denuding the endothelium, L-NAME (nitric oxide synthase inhibitor), and glyburide (KATP channel blocker) but was not affected by indomethacin (cyclooxygenase inhibitor), iberiotoxin [Ca2+-activated K+ channel (KCa) blocker], or 4-aminopyridine (KV channel blocker). Furthermore, GLP-1 increased outward K+ currents by enhancing the KATP channel in rat coronary arterial smooth muscle cells (RCASMCs). These results show that GLP-1 is an endothelial-dependent vasospasmolytic agent in the RCA and imply that the relaxant effect is regulated by enhancing KATP rather than KV or KCa currents in RCASMCs.

Inhibition of nitric oxide synthases prevents and reverses α,β-meATP-induced neck muscle nociception in mice

Cephalalgia ◽  
2010 ◽  
Vol 30 (10) ◽  
pp. 1225-1232 ◽  
Author(s):  
Jens Ellrich ◽  
Andreas Fischer ◽  
Joachim M Gilsbach ◽  
Anna Makowska ◽  
Peter Spangenberg
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Nitric Oxide Synthases ◽  
Neck Muscles ◽  
Neck Muscle ◽  
Dependent Manner ◽  
Nitric Oxide Synthase Inhibitor ◽  
Therapeutic Concepts ◽  
Synthase Inhibitor ◽  
Oxide Synthase

Introduction: Tension-type headache (TTH) is associated with noxious input from neck muscles. Intravenous administration of the unspecific nitric oxide synthase inhibitor L-NMMA in chronic TTH patients caused analgesia and reduction of neck muscle tenderness. Methods: The unspecific nitric oxide synthase inhibitor L-NMMA was applied in an experimental model for neck muscle nociception in anesthetized mice ( N = 25). Results: Local injection of α,β-meATP into semispinal neck muscles induced sustained facilitation of brainstem nociception as monitored by the jaw-opening reflex. Preceding intraperitoneal administration of L-NMMA (0.05, 0.1, 1 mg/kg) prevented reflex facilitation evoked by α,β-meATP in a dose-dependent manner. Intraperitoneal injection of L-NMMA subsequent to intramuscular α,β-meATP application reversed established brainstem reflex facilitation back to baseline values. Discussion: Both experiments with preceding and subsequent L-NMMA indicate the involvement of nitric oxide synthases in the induction and maintenance of facilitation. However, future experiments will have to address the involvement of various isoenzymes in order to provide for new therapeutic concepts in TTH.

Hydrogen sulfide as a mediator of endothelium-dependent relaxation evoked by Moringa oleifera leaf extract in mesenteric arterial beds isolated from L-NAME hypertensive rats

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Direk Aekthammarat ◽  
Panot Tangsucharit ◽  
Patchareewan Pannangpetch
Keyword(s):  
Nitric Oxide ◽  
Moringa Oleifera ◽  
Channel Blocker ◽  
Resistance Arteries ◽  
Hypertensive Rats ◽  
Nitric Oxide Synthase Inhibitor ◽  
Synthase Inhibitor ◽  
Gap Junctional ◽  
Oxide Synthase ◽  
Endothelium Dependent Relaxation

AbstractObjectivesAqueous extract of Moringa oleifera leaves (MOE) is a potent inducer of endothelium-dependent relaxation of mesenteric resistance arteries of rats induced to be hypertensive using Nω-nitro-L-arginine methyl ester (L-NAME). Hydrogen sulfide (H2S) has been shown to participate in endothelium-dependent relaxation of small resistance arteries. Therefore, this study aimed to investigate whether endothelial H2S-dependent signaling plays a role in the vasorelaxation in response to MOE.MethodsMesenteric arterial beds isolated from L-NAME hypertensive rats were set up in an ex vivo perfusion system for measurement of vasoreactivity. All experiments were performed in the presence of the nitric oxide synthase inhibitor, L-NAME (100 µM) and the cyclooxygenase inhibitor, indomethacin (10 µM) to prevent the formation of nitric oxide and prostanoids, respectively.ResultsIn the presence of the nitric oxide synthase inhibitor, L-NAME and the cyclooxygenase inhibitor, indomethacin, the endothelium-dependent vasorelaxation induced by MOE (0.001–3 mg) was completely inhibited by DL-propargylglycine (100 µM), which inhibits the H2Sgenerating enzyme, cystathionine γ-lyase. This H2Sdependent response was reduced by the KATP channel blocker; glibenclamide (10 µM), the KCa channel blocker; tetraethylammonium (1 µM), and the myo-endothelial gap-junctional uncoupler; 18α-glycyrrhetinic acid (10 µM). In contrast, the muscarinic receptor antagonist, atropine (100 µM), did not affect the response to MOE.ConclusionsThe results may suggest that H2S is the likely mediator of endothelium-dependent relaxation in response to MOE in mesenteric arterial beds of L-NAME-induced hypertensive rats. MOE-induced H2S-dependent vasorelaxation involves activation of KATP and KCa channels and requires myo-endothelial gap-junctional communication.

Prior episode of anoxia attenuates vasorelaxation in response to subsequent episode of anoxia

1994 ◽  
Vol 266 (3) ◽  
pp. H974-H979 ◽  
Author(s):  
B. C. Yang ◽  
J. L. Mehta
Keyword(s):  
Nitric Oxide ◽  
Methylene Blue ◽  
Superoxide Anion ◽  
Channel Blocker ◽  
Nitric Oxide Synthase Inhibitor ◽  
Subsequent Episode ◽  
Adenosine A1 ◽  
Synthase Inhibitor ◽  
Oxide Synthase

To examine the effect of a prior episode of anoxia on subsequent anoxia-mediated vasorelaxation, norepinephrine-precontracted endothelium-intact rat aortic rings were first exposed to anoxia (95% N2-5% CO2 for 5, 15, or 30 min) then to normoxia (95% O2-5% CO2 for 15 min). These rings were exposed again to anoxia for 30 min. First exposure of rings to anoxia for 30 min resulted in 77 +/- 4% decrease in tone (vasorelaxation), whereas second exposure resulted in only 10 +/- 4% relaxation (n = 11, P < 0.001 vs. relaxation during first exposure). First exposure of rings to anoxia for 5 or 15 min also diminished relaxation to 59 +/- 3 and 19 +/- 8%, respectively, on second exposure to anoxia (both P < 0.01 vs. relaxation during 1st anoxia). Attenuation of vasorelaxation by prior episode of anoxia was not affected by treatment of rings with indomethacin (10(-5) M), the Ca2+ channel blocker felodipine (10(-6) M), the superoxide anion scavenger superoxide dismutase (100 micrograms/ml), or adenosine A1 and A2 blockers (each 10(-6) M). To examine the role of intact functional endothelium in attenuation of vasorelaxation during second anoxic exposure, rings were deendothelialized and treated with the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA; 10(-4) M) or the guanylate cyclase inhibitor methylene blue (MB; 2 x 10(-5) M). In all deendothelialized rings, vasorelaxation during second anoxic exposure was similar to that during first anoxic exposure (100 +/- 0 vs. 98 +/- 3%, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Glomerular and tubular interactions between renal adrenergic activity and nitric oxide

1995 ◽  
Vol 268 (6) ◽  
pp. F1004-F1008 ◽  
Author(s):  
F. B. Gabbai ◽  
S. C. Thomson ◽  
O. Peterson ◽  
L. Wead ◽  
K. Malvey ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Glomerular Filtration ◽  
Renal Nerves ◽  
Ang Ii ◽  
Nitric Oxide Synthase Inhibitor ◽  
Adrenergic Activity ◽  
Single Nephron ◽  
Synthase Inhibitor ◽  
Oxide Synthase

Endothelium-dependent nitric oxide (EDNO) exerts control over the processes of glomerular filtration and tubular reabsorption. The importance of the renal nerves to the tonic influence of EDNO in the glomerular microcirculation and proximal tubule was tested by renal micropuncture in euvolemic adult male Munich-Wistar rats. The physical determinants of glomerular filtration and proximal reabsorption were assessed before and during administration of the nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA), in control animals and in animals 5–9 days after either ipsilateral surgical renal denervation (DNX) or after either sham surgery (SHX). L-NMMA caused single-nephron glomerular filtration rate to decline in control and SHX animals but not in DNX rats. L-NMMA caused a reduction in proximal reabsorption in control and SHX rats, which was prevented by prior DNX. DNX did not alter urinary guanosine 3',5'-cyclic monophosphate excretion, and, although DNX upregulates glomerular angiotensin II (ANG II) receptors, prior DNX did not alter intrarenal ANG II content as evaluated by radioimmunoassay. Some component of renal adrenergic activity is required for the full expression of the glomerular and tubular effects of blockade of nitric oxide synthase.

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