Nitric oxide attenuates endothelin-1-induced vasoconstriction in canine stomach

1996 ◽  
Vol 271 (1) ◽  
pp. G27-G35
Author(s):  
J. G. Wood ◽  
Q. Zhang ◽  
Z. Y. Yan ◽  
L. Y. Cheung

We previously observed that endothelin-1 (ET-1)-induced gastric vasoconstriction is enhanced after ischemia-reperfusion. The purpose of our present study was to examine the role of nitric oxide in regulating ET-1-induced vasoconstriction under normal conditions and after ischemia-reperfusion. Using a mechanically perfused stomach segment from chloralose-anesthetized dogs, we examined 1) responses to NG-nitro-L-arginine methyl ester (L-NAME) alone and in combination with L-arginine, 2) whether L-NAME affects ET-1-induced vasoconstriction under normal conditions and after ischemia-reperfusion, and 3) if spermine NONOate inverted question mark1,3-propanediamine-N-[4-1-(3-aminopropyl)-2-hydroxy-2-nitrosohydrazi no] butyl; a nitric oxide donor inverted question mark attenuates the augmented response to ET-1 after ischemia-reperfusion. Our results show that 1) L-NAME significantly increased baseline vascular resistance and this response was reduced by L-arginine, 2) ET-1-induced vasoconstriction was enhanced by L-NAME, and 3) administration of spermine NONOate during reperfusion largely attenuated the vasoconstrictor response to ET-1 after ischemia-reperfusion. Our findings are consistent with the hypothesis that nitric oxide modulates responses to ET-1 under normal conditions, and loss of this vasodilator after ischemia-reperfusion results in an augmented response to ET-1.

2006 ◽  
Vol 290 (1) ◽  
pp. R84-R89 ◽  
Author(s):  
Kazuhiko Takeuchi ◽  
Noriyuki Miyata ◽  
Marija Renic ◽  
David R. Harder ◽  
Richard J. Roman

Recent studies have indicated that 20-hydroxyeicosatetraenoic acid (20-HETE) contributes to the fall in cerebral blood flow (CBF) after subarachnoid hemorrhage (SAH), but the factors that stimulate the production of 20-HETE are unknown. This study examines the role of vasoactive factors released by clotting blood vs. the scavenging of nitric oxide (NO) by hemoglobin (Hb) in the fall in CBF after SAH. Intracisternal (icv) injection of blood produced a greater and more prolonged (120 vs. 30 min) decrease in CBF than that produced by a 4% solution of Hb. Pretreating rats with Nω-nitro-l-arginine methyl ester (l-NAME; 10 mg/kg iv) to block the synthesis of NO had no effect on the fall in CBF produced by an icv injection of blood. l-NAME enhanced rather than attenuated the fall in CBF produced by an icv injection of Hb. Blockade of the synthesis of 20-HETE with TS-011 (0.1 mg/kg iv) prevented the sustained fall in CBF produced by an icv injection of blood and the transient vasoconstrictor response to Hb. Hb (0.1%) reduced the diameter of the basilar artery (BA) of rats in vitro by 10 ± 2%. This response was reversed by TS-011 (100 nM). Pretreatment of vessels with l-NAME (300 μM) reduced the diameter of BA and blocked the subsequent vasoconstrictor response to the addition of Hb to the bath. TS-011 returned the diameter of vessels exposed to l-NAME and Hb to that of control. These results suggest that the fall in CBF after SAH is largely due to the release of vasoactive factors by clotting blood rather than the scavenging of NO by Hb and that 20-HETE contributes the vasoconstrictor response of cerebral vessels to both Hb and blood.


Endocrinology ◽  
2009 ◽  
Vol 150 (5) ◽  
pp. 2382-2387 ◽  
Author(s):  
Karim Sabrane ◽  
Markus-N. Kruse ◽  
Alexandra Gazinski ◽  
Michaela Kuhn

Atrial natriuretic peptide (ANP), via its guanylyl cyclase (GC)-A receptor, plays a key role in the regulation of arterial blood pressure (ABP) and volume. Endothelial-restricted deletion of GC-A in mice [endothelial cell (EC) GC-A knockout (KO)] resulted in hypervolemic hypertension, demonstrating that the endothelium participates in the hypotensive and hypovolemic actions of ANP. Published studies showed that ANP modulates the release of the vasoactive factors nitric oxide (NO) and endothelin-1 (ET-1) from cultured endothelia. Based on these observations, we examined the role of these endothelial factors in ANP-dependent vasodilatation (studied in isolated arteries) and chronic regulation of ABP (measured in awake mice by tail-cuff plethysmography). ANP induced concentration-dependent vasorelaxations of aortic, carotid, and pulmonary arteries. These responses were not different between control and EC GC-A KO mice, and were significantly enhanced after inhibition of NO synthase [by N(G)-nitro-l-arginine-methyl ester]. Intravenous administration of N(G)-nitro-l-arginine-methyl ester to conscious mice significantly increased ABP. The extent of these hypertensive reactions was similar in EC GC-A KO mice and control littermates (increases in systolic blood pressure by ∼25 mm Hg). Conversely, antagonism of ET-1/endothelin-A receptors with BQ-123 reduced ABP significantly and comparably in both genotypes (by ∼11 mm Hg). Finally, the vascular and tissue expression levels of components of the NO system and of immunoreactive ET-1 were not different in control and EC GC-A KO mice. We conclude that the endothelium, but not modulation of endothelial NO or ET-1, participates in the chronic regulation of ABP by ANP.


1998 ◽  
Vol 275 (1) ◽  
pp. H94-H99 ◽  
Author(s):  
S. Pudupakkam ◽  
K. A. Harris ◽  
W. G. Jamieson ◽  
G. DeRose ◽  
J. A. Scott ◽  
...  

We tested the hypothesis that ischemic preconditioning (PC) of skeletal muscle provided tolerance to a subsequent ischemic event 24 h later, and that such protection was due to nitric oxide (NO). Male Wistar rats, anesthetized with halothane, were randomly assigned to groups: ischemic (no PC; n = 11), PC ( n = 11), PC + N-nitro-l-arginine methyl ester (l-NAME; 100 μmol/l; n = 5), PC + N-nitro-d-arginine methyl ester (100 μmol/l; n= 4), PC + aminoguanidine (AMG; 100 μmol/l; n = 4), ischemic +l-NAME ( n= 4), or ischemic + AMG ( n = 4). PC consisted of 5× 10 min of ischemia and reperfusion, and, 24 h later, 2 h of ischemia were induced by a tourniquet applied to the limb. With the use of intravital microscopy, the number of perfused capillaries ( N pc) in the extensor digitorum longus (EDL) muscle was measured over a 90-min reperfusion period. The ratio of ethidium bromide- to bisbenzimide-labeled nuclei was used to estimate tissue injury. PC preserved N pc(23.6 ± 2.5) following 2 h of ischemia compared with sham muscles (11.5 ± 5.1), significantly elevating inducible NO synthase (iNOS) activity (81% increase), but did not afford protection to the parenchyma.l-NAME and AMG prevented ischemia-reperfusion-induced reduction in N pc in muscles without PC. However, after 90 min of reperfusion,l-NAME ( N pc = 15.0 ± 1.7), but not AMG ( N pc = 22.8 ± 3.1), significantly reduced the microvascular protection afforded by PC. We conclude that PC of the EDL muscle resulted, 24 h later, in protection to microvascular perfusion only, and that such protection was due to NO from sources other than iNOS.


1997 ◽  
Vol 9 (4) ◽  
pp. 433 ◽  
Author(s):  
María Beléen Herrero ◽  
J. Marcelo Viggiano ◽  
Silvina Pérez Martínez ◽  
Martha F. de Gimeno

In a recent work, we detected nitric oxide synthase (NO synthase) in the acrosome and tail of mouse and human spermatozoa by an immunofluorescence technique. Also, NO-synthase inhibitors added during sperm capacitationin vitro reduced the percentage of oocytes fertilized in vitro, suggesting a role for NO synthase in sperm function. Therefore, in the present study the effect of three NO-synthase inhibitors, NG-nitro-L-arginine methyl ester (L-NAME), NG-nitro-D-arginine methyl ester (D-NAME) and L-NG-nitro-arginine (NO2-arg), and of a nitric oxide donor, spermine-NONOate, on the progesterone-induced acrosome reaction of mouse sperm was examined. NO-synthase inhibitors were added at 0, 60 or 90 min during capacitation; at 120 min, mouse epididymal spermatozoa were exposed to 15 µM progesterone for another 15 min. In another set of experiments, different concentrations of spermine-NONOate were added to capacitated spermatozoa for 15 min; in these experiments, progesterone was not included. NO2-arg and L-NAME blocked progesterone-induced exocytosis regardless of the time at which these inhibitors were added. Moreover, D-NAME did not inhibit exocytosis. In contrast, spermine-NONOate stimulated the acrosomal exocytosis in vitro directly. These results provide evidence that mouse sperm NO synthase participates in the progesterone-induced acrosome reactionin vitro and that nitric oxide induces this event.


2006 ◽  
Vol 38 (5) ◽  
pp. 431-437 ◽  
Author(s):  
Hasan Fehmi Kucuk ◽  
Levent Kaptanoglu ◽  
Figen Ozalp ◽  
Necmi Kurt ◽  
Sadık Bingul ◽  
...  

2020 ◽  
Vol 16 ◽  
Author(s):  
Andrey Krylatov ◽  
Leonid Maslov ◽  
Sergey Y. Tsibulnikov ◽  
Nikita Voronkov ◽  
Alla Boshchenko ◽  
...  

: There is considerable evidence in the heart that autophagy in cardiomyocytes is activated by hypoxia/reoxygenation (H/R) or in hearts by ischemia/reperfusion (I/R). Depending upon the experimental model and duration of ischemia, increases in autophagy in this setting maybe beneficial (cardioprotective) or deleterious (exacerbate I/R injury). Aside from the conundrum as to whether or not autophagy is an adaptive process, it is clearly regulated by a number of diverse molecules including reactive oxygen species (ROS), various kinases, hydrogen sulfide (H2S) and nitric oxide (NO). The purpose this review is to address briefly the controversy regarding the role of autophagy in this setting and to examine a variety of disparate molecules that are involved in its regulation.


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