Modulation of cardiovascular control mechanisms and their interaction

1996 ◽  
Vol 76 (1) ◽  
pp. 193-244 ◽  
Author(s):  
P. B. Persson
Keyword(s):  
Nitric Oxide ◽  
Black Box ◽  
Control Element ◽  
Control Mechanisms ◽  
Severity Of Disease ◽  
The Brain ◽  
Specific Control ◽  
Central Level ◽  
Shed Light

It is generally held that the role of a specific control element can only be understood within its physiological environment. The reviewed studies make it clear that there is a potent interplay between locally produced substances such as adenosine, nitric oxide, prostaglandins, and various others all interacting with the central level of control. This can occur at central sites (e.g., nitric oxide in the brain) or in the periphery (e.g., neural influence on autoregulation). The interactions are more or less pronounced during specific physiological challenges. Furthermore, several of these interactions are altered under pathological circumstances, and in some cases, the interactions seem to maintain or even augment the severity of disease. When more than three parameters participate in an interaction, the resulting regulation may become extremely complex. If these parameters are nonlinearly coupled with each other, the only way to shed light onto the nature of control network is by treating it as a black box. With the use of spectral analysis or nonlinear methods, it is possible to disentangle the fundamental nature of the system in terms of the complexity and stability. Therefore, modern developments in cardiovascular physiology utilizing these techniques, some of which are derived from the "chaos theory," are reviewed.

scholarly journals Role of Nitric Oxide in Regulation of Brain Stem Circulation during Hypotension

1997 ◽  
Vol 17 (10) ◽  
pp. 1089-1096 ◽  
Author(s):  
Kazunori Toyoda ◽  
Kenichiro Fujii ◽  
Setsuro Ibayashi ◽  
Tetsuhiko Nagao ◽  
Takanari Kitazono ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Brain Stem ◽  
Topical Application ◽  
Basilar Artery ◽  
Group Versus ◽  
Control Group ◽  
Cranial Window ◽  
Severe Hypotension ◽  
The Brain

We tested the hypothesis that nitric oxide (NO) plays a role in CBF autoregulation in the brain stem during hypotension. In anesthetized rats, local CBF to the brain stem was determined with laser-Doppler flowmetry, and diameters of the basilar artery and its branches were measured through an open cranial window during stepwise hemorrhagic hypotension. During topical application of 10−5 mol/L and 10−4 mol/L Nω-nitro-L-arginine (L-NNA), a nonselective inhibitor of nitric oxide synthase (NOS), CBF started to decrease at higher steps of mean arterial blood pressure in proportion to the concentration of L-NNA in stepwise hypotension (45 to 60 mm Hg in the 10−5 mol/L and 60 to 75 mm Hg in the 10−4 mol/L L-NNA group versus 30 to 45 mm Hg in the control group). Dilator response of the basilar artery to severe hypotension was significantly attenuated by topical application of L-NNA (maximum dilatation at 30 mm Hg: 16 ± 8% in the 10−5 mol/L and 12 ± 5% in the 10−4 mol/L L-NNA group versus 34 ± 4% in the control group), but that of the branches was similar between the control and L-NNA groups. Topical application of 10−5 mol/L 7-nitro indazole, a selective inhibitor of neuronal NOS, did not affect changes in CBF or vessel diameter through the entire pressure range. Thus, endothelial but not neuronal NO seems to take part in the regulation of CBF to the the brain stem during hypotension around the lower limits of CBF autoregulation. The role of NO in mediating dilatation in response to hypotension appears to be greater in large arteries than in small ones.

New insights into the activity of Pseudomonas aeruginosa cd1 nitrite reductase

2008 ◽  
Vol 36 (6) ◽  
pp. 1155-1159 ◽  
Author(s):  
Serena Rinaldo ◽  
Alessandro Arcovito ◽  
Giorgio Giardina ◽  
Nicoletta Castiglione ◽  
Maurizio Brunori ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Nitrite Reductase ◽  
Nitrite Reduction ◽  
Nitrite Reductases ◽  
Cytochrome Cd1 ◽  
Haem Iron ◽  
Shed Light ◽  
Denitrification Process

The cytochrome cd1 nitrite reductases are enzymes that catalyse the reduction of nitrite to nitric oxide (NO) in the bacterial energy conversion denitrification process. These enzymes contain two different redox centres: one covalently bound c-haem, which is reduced by external donors, and one peculiar d1-haem, where catalysis occurs. In the present paper, we summarize the current understanding of the reaction of nitrite reduction in the light of the most recent results on the enzyme from Pseudomonas aeruginosa and discuss the differences between enzymes from different organisms. We have evidence that release of NO from the ferrous d1-haem occurs rapidly enough to be fully compatible with the turnover, in contrast with previous hypotheses, and that the substrate nitrite is able to displace NO from the d1-haem iron. These results shed light on the mechanistic details of the activity of cd1 nitrite reductases and on the biological role of the d1-haem, whose presence in this class of enzymes has to date been unexplained.

COVID-19 Beyond the Lungs

2022 ◽  
pp. 109-126
Author(s):  
Omar El Hiba ◽  
Hicham Chatoui ◽  
Nadia Zouhairi ◽  
Lahoucine Bahi ◽  
Lhoussaine Ammouta ◽  
...  
Keyword(s):  
Experimental Data ◽  
Nervous System ◽  
Clinical Symptoms ◽  
Case Reports ◽  
The World ◽  
Acute Pneumonia ◽  
The Brain ◽  
Cardinal Feature ◽  
Shed Light

Since December 2019, the world has been shaken by the spread of a highly pathogen virus, causing severe acute respiratory syndrome (SARS-Cov2), which emerged in Wuhan, China. SARS-Cov2 is known to cause acute pneumonia: the cardinal feature of coronavirus disease 2019 (COVID-19). Clinical features of the disease include respiratory distress, loss of spontaneous breathing, and sometimes neurologic signs such as headache and nausea and anosmia, leading to suppose a possible involvement of the nervous system as a potential target of SARS-CoV2. The chapter will shed light on the recent clinical and experimental data sustaining the involvement of the nervous system in the pathophysiology of COVID-19, based on several case reports and experimental data reporting the possible transmission of SARS-CoV2 throughout the peripheral nerves to the brain cardiorespiratory centers. Thus, understanding the role of the nervous system in the course of clinical symptoms of COVID-19 is important in determining the appropriate therapeutic approach to combat the disease.

scholarly journals Role of endothelial nitric oxide synthase-derived nitric oxide in activation and dysfunction of cerebrovascular endothelial cells during early onsets of sepsis

2008 ◽  
Vol 295 (4) ◽  
pp. H1712-H1719 ◽  
Author(s):  
Osamu Handa ◽  
Jancy Stephen ◽  
Gediminas Cepinskas
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Synthase ◽  
Mass Flux ◽  
Oxidant Stress ◽  
Junction Protein ◽  
Cerebrovascular Endothelial Cells ◽  
Oxide Synthase ◽  
The Brain

Sepsis-associated encephalopathy is an early manifestation of sepsis, resulting in a diffuse dysfunction of the brain. Recently, nitric oxide (NO) has been proposed to be one of the key molecules involved in the modulation of inflammatory responses in the brain. The aim of this study was to assess the role of NO in cerebrovascular endothelial cell activation/dysfunction during the early onsets of sepsis. To this end, we employed an in vitro model of sepsis in which cultured mouse cerebrovascular endothelial cells (MCVEC) were challenged with blood plasma (20% vol/vol) obtained from sham or septic (feces-induced peritonitis, FIP; 6 h) mice. Exposing MCVEC to FIP plasma for 1 h resulted in increased production of reactive oxygen species and NO as assessed by intracellular oxidation of oxidant-sensitive fluorochrome, dihydrorhodamine 123 (DHR 123), and nitrosation of NO-specific probe, DAF-FM, respectively. The latter events were accompanied by dissociation of tight junction protein, occludin, from MCVEC cytoskeletal framework and a subsequent increase in FITC-dextran (3-kDa mol mass) flux across MCVEC grown on the permeable cell culture supports, whereas Evans blue-BSA (65-kDa mol mass) or FITC-dextran (10-kDa mol mass) flux were not affected. FIP plasma-induced oxidant stress, occludin rearrangement, and MCVEC permeability were effectively attenuated by antioxidant, 1-pyrrolidinecarbodithioic acid (PDTC; 0.5 mM), or interfering with nitric oxide synthase (NOS) activity [0.1 mM nitro-l-arginine methyl ester (l-NAME) or endothelial NOS (eNOS)-deficient MCVEC]. However, treatment of MCVEC with PDTC failed to interfere with NO production, suggesting that septic plasma-induced oxidant stress in MCVEC is primarily a NO-dependent event. Taken together, these data indicate that during early sepsis, eNOS-derived NO exhibits proinflammatory characteristics and contributes to the activation and dysfunction of cerebrovascular endothelial cells.

scholarly journals Nitric Oxide: The Common Link in Different Forms of Dementia

2021 ◽  
Vol 6 (3) ◽  
pp. 322-326
Author(s):  
Dipak Kumar Dhar
Keyword(s):  
Nitric Oxide ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Nitrosative Stress ◽  
Keywords Dementia ◽  
Neurotoxic Effects ◽  
The Common ◽  
Cellular Pathogenesis ◽  
The Brain

Dementia broadly refers to a global decline in cognitive and higher functions of the brain. With the gradually increasing number of aging population, the incidence of dementia has been steadily rising and expected to increase further in the coming years. The causes and forms of dementia are wide-ranging and diverse, with Alzheimer’s disease being its best studied form. With increasing knowledge about various effects and mechanisms of nitric oxide, this chemical neurotransmitter appears to be the connecting link in the cellular pathogenesis of dementia. An exhaustive search of research articles, commentaries and books published from 1990s onwards was performed with various words and combinations linked to dementia and nitric oxide. The existing medical literature shows both neuroprotective and neurotoxic effects of nitric oxide. The present article intends to delve into this topic and provide a lucid understanding of the role of nitric oxide in dementia. Keywords: Dementia, Nitric Oxide, Alzheimer’s disease, excitotoxicity, nitrosative stress.

Targeted Circuit Manipulations in the Modeling of OCD

2017 ◽  
Author(s):  
Susanne E. Ahmari
Keyword(s):  
Neural Circuit ◽  
Brain Network ◽  
Repetitive Behaviors ◽  
Imaging Studies ◽  
Targeted Treatments ◽  
Excessive Grooming ◽  
The Brain ◽  
Shed Light ◽  
Deep Brain

Work in animal models has great potential to shed light on the neural circuit perturbations that lead to OCD-related behaviors. Circuit-specific manipulations allow testing of the causal role of the brain network abnormalities observed in clinical imaging studies, with a precision that is not possible in investigations in humans. In recent years, circuit-specific manipulations in animals using a range of technologies have confirmed that abnormalities in the cortico-striatal circuitry can produce repetitive behaviors, such as excessive grooming. This chapter summarizes these advances. Refining our understanding of the contribution of particular neural circuits to OCD-relevant behaviors can inform the development of anatomically targeted treatments, such as deep brain stimulation.

Comparative Genomic and Network Analysis of nNOS by Using Different Bioinformatics Approaches

2021 ◽  
Vol 18 ◽  
Author(s):  
Nymphaea Arora ◽  
Vikash Prashar ◽  
Tania Arora ◽  
Randeep Sidhu ◽  
Anshul Mishra ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Network Analysis ◽  
Nitric Oxide Synthase ◽  
Vascular Tone ◽  
Neuronal Nitric Oxide Synthase ◽  
Homologous Sequences ◽  
Airway Tone ◽  
Oxide Synthase ◽  
The Brain

Introduction: Nitric oxide (NO) is a diatomic free radical gaseous molecule that is formed from L-arginine through NOS (Nitric oxide synthase) catalyzed reaction. NO controls vascular tone (hence blood pressure), insulin secretion, airway tone, and peristalsis and is involved in angiogenesis (growth of new blood vessels) and in the development of the nervous system. In the CNS, NO is an important messenger molecule, which is involved in various major functions in the brain. NOS has been classified into three isoforms which include nNOS (neuronal NOS), eNOS (endothelial NOS), and iNOS (inducible NOS). NOS1 is localized on chromosome 12, consisting of 1434 amino acids and 161 KDa molecular weight. nNOS is involved in synaptic transmission, regulating the tone of smooth muscles, penile erection. We studied NOS1 gene and protein network analysis through in silico techniques as human nNOS sequence was fetched from GenBank, and its homologous sequences were retrieved through BLAST search. Moreover, the results of this study exploit the role of NOS1 in various pathways, which provide ways to regulate it in various neurodegenerative diseases. Background: Previous research has revealed the role of Nitric Oxide (NO) formed from L-arginine through NOS (Nitric Oxide Synthase) as a physiological inter/intracellular messenger in the central as well as the peripheral nervous system. The diverse functions of NOS include insulin secretion, airway tone, vascular tone regulation, and in the brain, it is involved in differentiation, development, synaptic plasticity, and neurosecretion. Objective: The objective of this study is to unravel the role of neuronal Nitric Oxide Synthase (nNOS) in different pathways and its involvement as a therapeutic target in various neurodegenerative disorders, which can surely provide ways to regulate its activity in different aspects. Materials and Methods: In this study, we employed various bioinformatics tools and databases, initiating the study by fetching the neuronal Nitric Oxide Synthase (nNOS) sequence(GenBank) to find its homologous sequences(BLAST) and then exploring its physical properties and post-translational modifications, enhancing the research by network analysis(STRING), leading to its functional enrichment(Panther). Results : The results positively support the hypothesis of its role in various pathways related to neurodegeneration., Its interacting partners are the probable therapeutic targets of various neurodegenerative diseases focusing on specifically multi-target analysis. Conclusion: This study considered the evolutionary trend of physical, chemical, and biological properties of NOS1 through different phyla. The neuronal Nitric Oxide Synthase (nNOS), being one of the three isoforms of NOS (Nitric Oxide Synthase), is found to be involved in more pathways than just forming Nitric Oxide. This research provides the base for further neurological research.

scholarly journals Nitric Oxide Synthesis and Regional Cerebral Blood Flow Responses to Hypercapnia and Hypoxia in the Rat

1993 ◽  
Vol 13 (1) ◽  
pp. 80-87 ◽  
Author(s):  
D. A. Pelligrino ◽  
H. M. Koenig ◽  
R. F. Albrecht
Keyword(s):  
Nitric Oxide ◽  
No Synthase ◽  
Nitric Oxide Synthesis ◽  
Cerebral Vasculature ◽  
Regional Cerebral Blood ◽  
Generating Capacity ◽  
Baseline Values ◽  
The Brain ◽  
Hyperemic Response

The role of nitric oxide (NO) synthesis in the cerebral hyperemic responses to hypercapnia and hypoxia was investigated in anesthetized rats. Regional CBF (rCBF) measurements were obtained in the cortex (CX), subcortex (SC), brainstem (BS), and cerebellum (CE) using radiolabeled microspheres. The rCBF responses to either hypercapnia (Paco2 = 70–80 mm Hg) or hypoxia (Paco2 = 40–45 mm Hg) were compared in rat groups studied in the presence and absence of NO synthase inhibition induced via the intravenous infusion of nitro-l-arginine methyl ester (l-NAME, 3 mg kg−1 min−1). Administration of l-NAME under normocapnic/normoxic conditions produced a 40–60% reduction in baseline rCBF values, indicating the presence of a NO “tone” in the cerebral vasculature. Infusion of l-NAME resulted in a substantial attenuation, in all regions measured, of the rCBF increases that normally accompany hypercapnia. In comparing saline-infused to l-NAME-infused rats, the percentage increases in rCBF (from normocapnic baseline values) were 351% versus 166% (CX), 446% versus 199% (SC), 443% versus 206% (BS), and 483% versus 174% (CE), respectively. The rCBF changes from baseline (ΔrCBF in ml 100 g−1 min−1) were 488 versus 57 (CX), 570 versus 60 (SC), 434 versus 72 (BS), and 393 versus 45 (CE), respectively. These differences were all statistically significant ( p < 0.05). During hypoxia, when compared to rats not given l-NAME, inhibition of NO synthase activity resulted in significantly greater ( p < 0.05) percentage increases in rCBF (from normoxic baseline values) in most regions. The changes in non-l-NAME- vs. l-NAME-infused rats were 156% versus 262% (CX), 181% versus 309% (SC), and 210% versus 462% (BS), respectively. When the ΔrCBF values (from normoxic baseline levels) were compared, the changes were greater in the l-NAME group, but the differences were statistically insignificant. The results of this study indicated that NO synthesis is critically involved in the cerebral hyperemic response to hypercapnia but not hypoxia. In fact, the data obtained in the hypoxic groups suggested that reductions in O2 supply may inhibit the NO-generating capacity in the brain.

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