Endogenous Production of Nitric Oxide and Effects of Nitric Oxide and Superoxide on Melanotrope Functioning in the Pituitary Pars Intermedia of Xenopus laevis

Nitric Oxide ◽  
2000 ◽  
Vol 4 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Wilfried Allaerts ◽  
Werner J.H. Koopman ◽  
Bert P.J. Verlaan ◽  
Marco Buzzi ◽  
Peter A. Steerenberg
Keyword(s):  
Nitric Oxide ◽  
Xenopus Laevis ◽  
Pars Intermedia ◽  
Endogenous Production

scholarly journals Nitric Oxide is Involved in Metamorphic Processes in the Anuran Tadpole, Xenopus laevis

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Jennifer A. Johnson ◽  
E. Eileen Gardner ◽  
Jaishri Menon
Keyword(s):  
Nitric Oxide ◽  
Xenopus Laevis ◽  
Anuran Tadpole

scholarly journals Functional implications of nitric oxide produced by mitochondria in mitochondrial metabolism

1998 ◽  
Vol 332 (3) ◽  
pp. 673-679 ◽  
Author(s):  
Cecilia GIULIVI
Keyword(s):  
Nitric Oxide ◽  
Cytochrome Oxidase ◽  
Atp Synthesis ◽  
Competitive Inhibitor ◽  
Mitochondrial Metabolism ◽  
No Production ◽  
Endogenous Production ◽  
Mitochondrial Nitric Oxide Synthase ◽  
Energy Dependent ◽  
Oxide Synthase

The effects of endogenous production of NO•, catalysed by the mitochondrial nitric oxide synthase (NOS), on mitochondrial metabolism were studied. The respiratory rates of intact mitochondria in State 4 were decreased by 40% and 28% with succinate and malate–glutamate, respectively, in the presence of l-arginine (l-Arg); conversely, the O2 uptake with NG-methyl-l-arginine (NMMA), a competitive inhibitor of NOS, was increased. The production of NO• and the inhibition of the respiratory rates were dependent on the metabolic state in which mitochondria were maintained: NO• production was probably supported by mitochondrial NADPH, the latter maintained by the energy-dependent transhydrogenase. In addition to the decline in the respiratory rate, an inhibition of ATP synthesis was also observed (40–50%) following supplementation with l-Arg. The dependence of the respiratory rates of mitochondria in State 3 and cytochrome oxidase activities on O2 concentrations with either l-Arg or NMMA indicated that both processes were competitively inhibited by NO• at the cytochrome oxidase level. This inhibition can be explained by the interaction of NO• with cytochrome oxidase at the binuclear centre. The role of NO• as a physiological modulator of cytochrome oxidase is discussed in terms of cellular metabolism.

Endogenous Production of Nitric Oxide in Neonatal Endotoxemia 1683

1998 ◽  
Vol 43 ◽  
pp. 287-287
Author(s):  
Harold A Kaftan ◽  
Perry L Clark ◽  
Michael Norberg ◽  
Donald W Thibeault ◽  
William E Truog
Keyword(s):  
Nitric Oxide ◽  
Endogenous Production

scholarly journals Nitric oxide modulation of the electrically excitable skin of Xenopus laevis frog tadpoles

2007 ◽  
Vol 210 (22) ◽  
pp. 3910-3918 ◽  
Author(s):  
M. H. Alpert ◽  
H. Zhang ◽  
M. Molinari ◽  
W. J. Heitler ◽  
K. T. Sillar
Keyword(s):  
Nitric Oxide ◽  
Xenopus Laevis ◽  
Frog Tadpoles

The distribution of NADPH-diaphorase-labelled interneurons and the role of nitric oxide in the swimming system of Xenopus laevis larvae

2000 ◽  
Vol 203 (4) ◽  
pp. 705-713 ◽  
Author(s):  
D.L. McLean ◽  
K.T. Sillar
Keyword(s):  
Nitric Oxide ◽  
Xenopus Laevis ◽  
Swimming Activity ◽  
Nadph Diaphorase ◽  
Membrane Properties ◽  
Neuronal Membrane ◽  
Cycle Period ◽  
No Donor ◽  
Nos Inhibitors

The possible involvement of the free radical gas nitric oxide (NO) in the modulation of spinal rhythm-generating networks has been studied using Xenopus laevis larvae. Using NADPH-diaphorase histochemistry, three putative populations of nitric oxide synthase (NOS)-containing cells were identified in the brainstem. The position and morphology of the largest and most caudal population suggested that a proportion of these neurons is reticulospinal. The possible contribution of nitrergic neurons to the control of swimming activity was examined by manipulating exogenous and endogenous NO concentrations in vivo with an NO donor (SNAP, 100–500 micromol l(−)(1)) and NOS inhibitors (l-NAME and l-NNA, 0.5-5 mmol l(−)(1)), respectively. In the presence of SNAP, swim episode duration decreased and cycle period increased, whereas the NOS inhibitors had the opposite effects. We conclude from these data that the endogenous release of NO from brainstem neurons extrinsic to the spinal cord of Xenopus laevis larvae exerts a continuous modulatory influence on swimming activity, functioning like a ‘brake’. Although the exact level at which NO impinges upon the swimming rhythm generator has yet to be determined, the predominantly inhibitory effect of NO suggests that the underlying mechanisms of NO action could involve modulation of synaptic transmission and/or direct effects on neuronal membrane properties.

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