The Relationship between Myoglobin, Aerobic Capacity, Nitric Oxide Synthase Activity and Mitochondrial Function in Fish Hearts

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1072
Lucie Gerber ◽  
Kathy A. Clow ◽  
William R. Driedzic ◽  
Anthony K. Gamperl

The dynamic interactions between nitric oxide (NO) and myoglobin (Mb) in the cardiovascular system have received considerable attention. The loss of Mb, the principal O2 carrier and a NO scavenger/producer, in the heart of some red-blooded fishes provides a unique opportunity for assessing this globin’s role in NO homeostasis and mitochondrial function. We measured Mb content, activities of enzymes of NO and aerobic metabolism [NO Synthase (NOS) and citrate synthase, respectively] and mitochondrial parameters [Complex-I and -I+II respiration, coupling efficiency, reactive oxygen species production/release rates and mitochondrial sensitivity to inhibition by NO (i.e., NO IC50)] in the heart of three species of red-blooded fish. The expression of Mb correlated positively with NOS activity and NO IC50, with low NOS activity and a reduced NO IC50 in the Mb-lacking lumpfish (Cyclopterus lumpus) as compared to the Mb-expressing Atlantic salmon (Salmo salar) and short-horned sculpin (Myoxocephalus scorpius). Collectively, our data show that NO levels are fine-tuned so that NO homeostasis and mitochondrial function are preserved; indicate that compensatory mechanisms are in place to tightly regulate [NO] and mitochondrial function in a species without Mb; and strongly suggest that the NO IC50 for oxidative phosphorylation is closely related to a fish’s hypoxia tolerance.

1993 ◽  
Vol 289 (2) ◽  
pp. 357-361 ◽  
G Werner-Felmayer ◽  
E R Werner ◽  
D Fuchs ◽  
A Hausen ◽  
B Mayer ◽  

We show here that the human cervix carcinoma cell line ME-180 expresses a constitutive nitric oxide (NO) synthase, as demonstrated by formation of [3H]citrulline and nitrite. The enzyme is dependent on tetrahydrobiopterin, NADPH, flavins and Ca2+/calmodulin. Enzyme activity is located in the cytosol rather than in the membrane fraction and can be inhibited by NG-monomethyl-L-arginine (NMMA). An antiserum to NO synthase purified from porcine cerebellum inhibited the enzyme activity. ME-180 cells released NO, as was shown by stimulation of guanylate cyclase (EC in RFL-6 detector cells; this release was stimulated 8-fold by the Ca2+ ionophore A23187 and 2-fold by increasing the intracellular tetrahydrobiopterin levels with cytokines. This is the first characterization of a Ca2+/calmodulin-dependent NO synthase activity in human epithelial-type tumour cells.

2003 ◽  
Vol 284 (1) ◽  
pp. H299-H308 ◽  
Gilles Lebuffe ◽  
Paul T. Schumacker ◽  
Zuo-Hui Shao ◽  
Travis Anderson ◽  
Hirotoro Iwase ◽  

Reactive oxygen species (ROS) and nitric oxide (NO) are implicated in induction of ischemic preconditioning. However, the relationship between these oxidant signals and opening of the mitochondrial ATP-dependent potassium (KATP) channel during early preconditioning is not fully understood. We observed preconditioning protection by hypoxia, exogenous H2O2, or PKC activator PMA in cardiomyocytes subjected to 1-h ischemia and 3-h reperfusion. Protection was abolished by KATP channel blocker 5-hydroxydecanoate (5-HD) in each case, indicating that these triggers must act upstream from the KATP channel. Inhibitors of NO synthase abolished protection in preconditioned cells, suggesting that NO is also required for protection. DAF-2 fluorescence (NO sensitive) increased during hypoxic triggering. This was amplified by pinacidil and inhibited by 5-HD, indicating that NO is generated subsequent to KATP channel activation. Exogenous NO during the triggering phase conferred protection blocked by 5-HD. Exogenous NO also restored protection abolished by 5-HD or N ω-nitro-l-arginine methyl ester in preconditioned cells. Antioxidants given during pinacidil or NO triggering abolished protection, confirming that ROS are generated by KATP channel activation. Coadministration of H2O2 and NO restored PMA-induced protection in 5-HD-treated cells, indicating that ROS and NO are required downstream from the KATP channel. We conclude that ROS can trigger preconditioning by causing activation of the KATP channel, which then induces generation of ROS and NO that are both required for preconditioning protection.

1995 ◽  
Vol 79 (4) ◽  
pp. 1088-1092 ◽  
M. M. Kurrek ◽  
L. Castillo ◽  
K. D. Bloch ◽  
S. R. Tannenbaum ◽  
W. M. Zapol

Nitric oxide (NO) has been demonstrated to decrease its own synthesis in tissue preparations. We tested the hypothesis that endogenous NO synthesis induced by lipopolysaccharides (LPS) would be decreased by exogenous NO during isolated lung perfusion. Rats were pretreated with either saline or LPS 48 h before lung harvest. Endogenous NO synthase activity was measured as conversion of L-[14C]-arginine to L-[14C]citrulline during 90 min of perfusion. NO (100 ppm) was added to the ventilating gas during perfusion of lungs from one group of control or LPS-treated rats. A second group of control or LPS-treated rats was exposed chronically to 100 ppm NO for the 48 h before lung harvest, in addition to receiving 100 ppm NO added to the ventilating gas during lung perfusion. We conclude that conversion of L-[14C]arginine to L-[14C]citrulline was minimal in control lungs and increased in response to LPS pretreatment. NO added to the ventilating gas for the 90 min of ex vivo perfusion did not alter the rate of L-[14C]citrulline production. In vivo exposure to 100 ppm NO for 48 h did not alter the induction of inducible NO synthase activity as measured during ex vivo lung perfusion. This indicates that inhaled NO does not exert negative-feedback inhibition on inducible NO synthase in the ex vivo rat lung.

2012 ◽  
Vol 58 (5) ◽  
pp. 549-555
G.P. Kopylchuk ◽  
I.A. Shmarakov ◽  
I.M. Buchkovska ◽  
M.M. Marchenko ◽  
W.S. Blaner

p-Hydroxylase and N-demethylase activities of cytochrome P450 system, NO-synthase activity and the intensity of nitric oxide and superoxide anion production in mitochondrial, postmicrosomal and microsomal cellular fractions were studied in mouse liver under conditions of retinoid stores absence.It is determined, that under conditions of retinoid stores absence the activation of NO-synthase is occurring with decreased p-hydroxylase activity of cytochrome P450 system. The results of the generation intensity analysis showed the level of NO and О2- in liver mitochondrial fraction of knock-out mice, and changes in NADPH-dependent О2- production in microsomal fraction of mouse liver cells.

Cephalalgia ◽  
2010 ◽  
Vol 30 (11) ◽  
pp. 1354-1365 ◽  
Bart J Van der Schueren ◽  
Frederik H Verbrugge ◽  
René Verbesselt ◽  
Anne Van Hecken ◽  
Marleen Depré ◽  

Objectives: To assess whether migraine patients display a chronic nitric oxide synthase (NOS) hyperactivity by comparing the nitric oxide (NO) production before and following a loading dose of L-arginine between migraine patients (interictally) and matched healthy control subjects. In addition, we evaluated whether a loading dose of L-arginine triggers an acute migraine headache in migraineurs. Subjects and methods: Twenty healthy subjects and 20 migraine patients participated in a 2-period, randomised, double-blind, placebo-controlled study. Each subject received a 30-min infusion, by peripheral vein, of 30 g L-arginine hydrochloride or placebo (i.e. an equal volume of 0.9% saline solution). Meanwhile, biomarkers associated with the L-arginine–NO pathway (i.e. exhaled NO/nasal NO), plasma citrulline and urinary excretion of nitrite/nitrate and cGMP were assessed before and for 6 h following the start of the infusion. Results: At baseline, exhaled NO and nasal NO were higher in migraineurs compared to healthy subjects (mean ± 95% confidence interval): 15.9 (8.8, 23.0) parts per billion (ppb) versus 10.8 (7.0, 14.5) ppb for exhaled NO ( P = 0.04) and 76.3 (61.2, 91.4) versus 61.6 (51.2, 72.0) ppb for nasal NO ( P = 0.03), respectively. The AUC0–6 in ppb for exhaled NO and nasal NO following L-arginine or saline infusion did not differ between both groups. The increase in L-citrulline, following L-arginine infusion, was smaller in migraine patients (15 (13, 18) µmol/l) compared to healthy volunteers (19 (16, 23) µmol/l; P = 0.046). In healthy subjects, both nitrate and cGMP excretion were higher following L-arginine compared to placebo infusion: 132.63 (100.24, 165.02) versus 92.07 (66.33, 117.82) µmol/mmol creatinine for nitrate ( P = 0.014) and 50.53 (42.19, 58.87) versus 39.64 (33.94, 45.34) nmol/mmol creatinine for cGMP ( P = 0.0003), respectively. In migraineurs, excretion of these biomarkers was comparable following L-arginine or saline infusion. Conclusions: The results of the present study do not support the idea of a generalised increase in NO synthase activity in migraine patients outside of a migraine attack. The smaller increase in plasma L-citrulline, urinary nitrate and cGMP excretion following L-arginine infusion in migraine patients might indicate dysfunction of endothelial NO synthase.

1994 ◽  
Vol 267 (2) ◽  
pp. G270-G275 ◽  
K. Nichols ◽  
W. Staines ◽  
S. Rubin ◽  
A. Krantis

NO is produced within peripheral blood vessels through the action of the differentially distributed constitutive and inducible NO synthase isoforms in the vessel wall. As in other sites in the periphery, NO exerts local vasodilatory actions in the gastrointestinal microvasculature and is proposed to play a role in enteric vasomotor regulation. Using NO synthase histochemistry and endothelial cell immunohistochemistry, we provide the first anatomic evidence of NO synthesis in both endothelial and smooth muscle cells of submucosal blood vessels in the rat and human intestine. The findings of this study indicate that 1) as in the periphery, both the endothelial and vascular smooth muscle cells of the microvessels irrigating the rat and human intestinal wall possess NO synthesis potential, 2) NO synthase activity is predominantly localized to discrete subcellular patches, and 3) the source of NO within the vascular wall, either intimal or medial, should be a consideration in future studies in terms of the relative contribution of these sources of vasomotor tone in the rat and human gut wall.

2016 ◽  
Vol 310 (10) ◽  
pp. R896-R905 ◽  
Valter Dantonio ◽  
Marcelo E. Batalhão ◽  
Marcia H. M. R. Fernandes ◽  
Evilin N. Komegae ◽  
Gabriela A. Buqui ◽  

Nitric oxide (NO) plays a role in thermogenesis but does not mediate immune-to-brain febrigenic signaling in rats. There are suggestions of a different situation in birds, but the underlying evidence is not compelling. The present study was designed to clarify this matter in 5-day-old chicks challenged with a low or high dose of bacterial LPS. The lower LPS dose (2 μg/kg im) induced fever at 3–5 h postinjection, whereas 100 μg/kg im decreased core body temperature (Tc) (at 1 h) followed by fever (at 4 or 5 h). Plasma nitrate levels increased 4 h after LPS injection, but they were not correlated with the magnitude of fever. The NO synthase inhibitor ( NG-nitro-l-arginine methyl ester, l-NAME; 50 mg/kg im) attenuated the fever induced by either dose of LPS and enhanced the magnitude of the Tc reduction induced by the high dose in chicks at 31–32°C. These effects were associated with suppression of metabolic rate, at least in the case of the high LPS dose. Conversely, the effects of l-NAME on Tc disappeared in chicks maintained at 35–36°C, suggesting that febrigenic signaling was essentially unaffected. Accordingly, the LPS-induced rise in the brain level of PGE2 was not affected by l-NAME. Moreover, l-NAME augmented LPS-induced huddling, which is indicative of compensatory mechanisms to run fever in the face of attenuated thermogenesis. Therefore, as in rats, systemic inhibition of NO synthesis attenuates LPS-induced fever in chicks by affecting thermoeffector activity and not by interfering with immune-to-brain signaling. This may constitute a conserved effect of NO in endotherms.

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