Role of cerebral fluids in control of respiration as studied in unanesthetized goats

Respiratory responses to inhaled CO2 were measured in unanesthetized goats during repeated perfusions of the ventriculocisternal system through chronically implanted cannulas. [HCO3–] and pH were measured in carotid loop blood and cisternal outflow. Average steady-state alveolar ventilation increased fourfold when cerebrospinal fluid (CSF)-[HCO3–] was reduced from 30 to 15 mm/liter at constant, normal CO2 pressure or threefold when CSF pH changed from 7.32 to 7.21 at constant, normal CSF-[HCO3–]. Sensitivity was two- to sevenfold greater than reported for anesthetized animals. At constant CSF pH the ventilatory response to inhaled CO2 was 60% of the isobicarbonate response. Pco2 in cisternal outflow was shown to approximate that in cerebral tissue. HCO3– flux was measured as a function of CSF-[HCO3–] and concentration profiles between CSF and capillary blood were considered. Alveolar ventilation is a single linear function of [H+] in tissue fluid located two-thirds to three-fourths of the distance along the functional concentration gradient of HCO3– between CSF and blood at all values of Pco2 and CSF-[HCO3–] which we investigated.

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Brain hypoxia and control of breathing: role of the vagi

Journal of Applied Physiology ◽

10.1152/jappl.1982.53.1.212 ◽

1982 ◽

Vol 53 (1) ◽

pp. 212-217 ◽

Cited By ~ 4

Author(s):

R. W. Chapman ◽

T. V. Santiago ◽

N. H. Edelman

Keyword(s):

Ventilatory Response ◽

Control Of Breathing ◽

Inspiratory Time ◽

Small Magnitude ◽

Lung Inflation ◽

Brain Hypoxia ◽

And Control ◽

Respiratory Responses ◽

Spontaneous Breath

Vagally mediated reflexes play an important role in the generation of respiratory responses to various stimuli. This study examined the role of vagally mediated mechanisms in the generation of the respiratory responses to progressive brain hypoxia secondary to carboxyhemoglobinemia (HbCO 013;55%) in six unanesthetized goats. Ventilation, respiratory cycle timing, and the lung inflation reflex were measured before and during CO inhalation in intact and bilaterally vagotomized animals. Our results indicate that vagal reflexes contribute a small magnitude of the hyperpnea caused by carboxyhemoglobinemia. Furthermore, in contrast to that reported for CO2 inhalation, the tachypneic nature of the ventilatory response to CO is not a vagally mediated phenomenon. CO inhalation had a biphasic influence on the strength of the lung inflation reflex measured as the ratio of inspiratory time during occlusion (TIoccl) to inspiratory time of the preceding spontaneous breath (TIspont). At HbCO levels of 35%, TIoccl/TIspont was enhanced, whereas at HbCO levels of 55% of ratio fell to unity, indicating abolition of the reflex. After vagotomy, this ratio was unity at all levels of carboxyhemoglobinemia.

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Central chemical regulation of respiration in term newborn

Journal of Applied Physiology ◽

10.1152/jappl.1979.47.6.1212 ◽

1979 ◽

Vol 47 (6) ◽

pp. 1212-1217 ◽

Cited By ~ 6

Author(s):

M. A. Bureau ◽

R. Begin ◽

Y. Berthiaume

Keyword(s):

Cerebrospinal Fluid ◽

Ventilatory Response ◽

Rapid Change ◽

Regulation Of Respiration ◽

Ph Change ◽

Progressive Change ◽

Arterial Ph ◽

Newborn Animals ◽

Sequential Measurements

The role of the medullary H+-sensitive chemoreceptors on the drive of breathing was studied in 10 unanesthetized newborn animals (8 lambs and 2 kids). The experiment consisted of sequential measurements of ventilation (VE) during a progressive change in the arterial pH (pHa) and in the pH of the cisternal cerebrospinal fluid (pHCSF), induced by intravenous infusion of hydrochloric acid (HCl) followed after an 8-h steady state of acidosis by rapid bicarbonate [HCO3-] infusion. It is shown that a rapid change in [HCO3-]CSF occurs during the infusion of HCl or NaHCO3. As a consequence both CSF and arterial pH change in the the same direction and large changes in pHCSF (from 7.331 to 7.227) were observed. Such CSF acidosis did not contribute to further increase VE beyond the level by hyperventilation induced by the initial fall of pHa. The ventilatory response to the decrease in pHa was found to fall off with moderate to severe acidosis (pHa less than 7.20). In conclusion, this study demonstrates an instability of the pHCSF during neonatal metabolic acidosis and it suggests an immaturity of both the H+-sensitive medullary and peripheral chemoreceptors in the 8-day-old newborns.

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Central chemical control of ventilation and response of turtles to inspired CO2

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1985.249.3.r323 ◽

1985 ◽

Vol 249 (3) ◽

pp. R323-R328 ◽

Cited By ~ 4

Author(s):

B. M. Hitzig ◽

J. C. Allen ◽

D. C. Jackson

Keyword(s):

Cerebrospinal Fluid ◽

Tidal Volume ◽

Chemical Control ◽

Ventilatory Response ◽

Freshwater Turtles ◽

Acid Base ◽

Ventilatory Responses ◽

Acid Base Status ◽

Homeostatic Mechanisms

The role of central chemosensors in the overall ventilatory response of freshwater turtles (Chrysemys scripta elegans) to the addition of CO2 in inspired gas was measured. Centrally mediated ventilatory responses were isolated in the unanesthetized animal by combining CO2 breathing and brain ventricular perfusion with mock cerebrospinal fluid (CSF) of varying acid-base status. Breathing 4.5% CO2 resulted in increases in both ventilatory frequency (f) and tidal volume (VT), with increases in VT providing most of the overall ventilatory change. Alterations in the acid-base status of the perfusate produced highly significant changes in f. VT changes were divorced from the acid-base status of the mock CSF perfusate. We therefore conclude that ventilatory changes in turtles, mediated by central chemosensors, are primarily affected by alterations in f. VT changes, associated with acid-base homeostatic mechanisms, are mediated by receptors outside the blood-brain barrier in these animals. On the basis of these data, we hypothesize that the increase in f observed when turtles breathe 4.5% CO2 is primarily mediated by the central chemosensors.

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Fibrinolytic Activity of Cerebro-Spinal Fluid and the Development of Artificial Cerebral Haematomas in Dogs

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653538 ◽

1969 ◽

Vol 21 (02) ◽

pp. 294-303 ◽

Cited By ~ 3

Author(s):

H Mihara ◽

T Fujii ◽

S Okamoto

Keyword(s):

Cerebrospinal Fluid ◽

Carboxylic Acid ◽

Fibrinolytic Activity ◽

Clinical Implications ◽

Trans Form ◽

Plate Method ◽

Blood Samples ◽

Fibrin Plate ◽

The Brain

SummaryBlood was injected into the brains of dogs to produce artificial haematomas, and paraffin injected to produce intracerebral paraffin masses. Cerebrospinal fluid (CSF) and peripheral blood samples were withdrawn at regular intervals and their fibrinolytic activities estimated by the fibrin plate method. Trans-form aminomethylcyclohexane-carboxylic acid (t-AMCHA) was administered to some individuals. Genera] relationships were found between changes in CSF fibrinolytic activity, area of tissue damage and survival time. t-AMCHA was clearly beneficial to those animals given a programme of administration. Tissue activator was extracted from the brain tissue after death or sacrifice for haematoma examination. The possible role of tissue activator in relation to haematoma development, and clinical implications of the results, are discussed.

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The Role of Diamox and High-Volume Lumbar Puncture for Treatment of Iatrogenic Postoperative Cerebrospinal Fluid Leak

10.1055/s-0040-1702473 ◽

2020 ◽

Author(s):

Aria Jamshidi ◽

Aashish Shah ◽

Rick Komotar ◽

Michael Ivan

Keyword(s):

Cerebrospinal Fluid ◽

Lumbar Puncture ◽

Cerebrospinal Fluid Leak ◽

High Volume ◽

Fluid Leak

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Faculty Opinions recommendation of Cerebrospinal fluid metabolomics identifies a key role of isocitrate dehydrogenase in bipolar disorder: evidence in support of mitochondrial dysfunction hypothesis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.726084834.793526786 ◽

2016 ◽

Author(s):

Victor Reus

Keyword(s):

Bipolar Disorder ◽

Cerebrospinal Fluid ◽

Mitochondrial Dysfunction ◽

Isocitrate Dehydrogenase

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Efficient aortic lymphatic drainage is necessary for atherosclerosis regression induced by ezetimibe

Science Advances ◽

10.1126/sciadv.abc2697 ◽

2020 ◽

Vol 6 (50) ◽

pp. eabc2697

Author(s):

Kim Pin Yeo ◽

Hwee Ying Lim ◽

Chung Hwee Thiam ◽

Syaza Hazwany Azhar ◽

Caris Tan ◽

...

Keyword(s):

Lymphatic Vessels ◽

Lymphatic Drainage ◽

Lymphatic Transport ◽

Atherosclerotic Plaques ◽

Tissue Fluid ◽

Atherosclerosis Progression ◽

Lymphatic Vasculature ◽

Lesion Regression ◽

Transport Of Macromolecules

A functional lymphatic vasculature is essential for tissue fluid homeostasis, immunity, and lipid clearance. Although atherosclerosis has been linked to adventitial lymphangiogenesis, the functionality of aortic lymphatic vessels draining the diseased aorta has never been assessed and the role of lymphatic drainage in atherogenesis is not well understood. We develop a method to measure aortic lymphatic transport of macromolecules and show that it is impaired during atherosclerosis progression, whereas it is ameliorated during lesion regression induced by ezetimibe. Disruption of aortic lymph flow by lymphatic ligation promotes adventitial inflammation and development of atherosclerotic plaque in hypercholesterolemic mice and inhibits ezetimibe-induced atherosclerosis regression. Thus, progression of atherosclerotic plaques may result not only from increased entry of atherogenic factors into the arterial wall but also from reduced lymphatic clearance of these factors as a result of aortic lymph stasis. Our findings suggest that promoting lymphatic drainage might be effective for treating atherosclerosis.

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Plasma and cerebrospinal fluid inflammation and the blood-brain barrier in older surgical patients: the Role of Inflammation after Surgery for Elders (RISE) study

Journal of Neuroinflammation ◽

10.1186/s12974-021-02145-8 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Sarinnapha M. Vasunilashorn ◽

◽

Long H. Ngo ◽

Simon T. Dillon ◽

Tamara G. Fong ◽

...

Keyword(s):

Cerebrospinal Fluid ◽

Blood Brain Barrier ◽

Plasma Levels ◽

Inflammatory Markers ◽

Brain Barrier ◽

Markers Of Inflammation ◽

Blood Brain ◽

Csf Levels ◽

The Relationship

Abstract Background Our understanding of the relationship between plasma and cerebrospinal fluid (CSF) remains limited, which poses an obstacle to the identification of blood-based markers of neuroinflammatory disorders. To better understand the relationship between peripheral and central nervous system (CNS) markers of inflammation before and after surgery, we aimed to examine whether surgery compromises the blood-brain barrier (BBB), evaluate postoperative changes in inflammatory markers, and assess the correlations between plasma and CSF levels of inflammation. Methods We examined the Role of Inflammation after Surgery for Elders (RISE) study of adults aged ≥ 65 who underwent elective hip or knee surgery under spinal anesthesia who had plasma and CSF samples collected at baseline and postoperative 1 month (PO1MO) (n = 29). Plasma and CSF levels of three inflammatory markers previously identified as increasing after surgery were measured using enzyme-linked immunosorbent assay: interleukin-6 (IL-6), C-reactive protein (CRP), and chitinase 3-like protein (also known as YKL-40). The integrity of the BBB was computed as the ratio of CSF/plasma albumin levels (Qalb). Mean Qalb and levels of inflammation were compared between baseline and PO1MO. Spearman correlation coefficients were used to determine the correlation between biofluids. Results Mean Qalb did not change between baseline and PO1MO. Mean plasma and CSF levels of CRP and plasma levels of YKL-40 and IL-6 were higher on PO1MO relative to baseline, with a disproportionally higher increase in CRP CSF levels relative to plasma levels (CRP tripled in CSF vs. increased 10% in plasma). Significant plasma-CSF correlations for CRP (baseline r = 0.70 and PO1MO r = 0.89, p < .01 for both) and IL-6 (PO1MO r = 0.48, p < .01) were observed, with higher correlations on PO1MO compared with baseline. Conclusions In this elective surgical sample of older adults, BBB integrity was similar between baseline and PO1MO, plasma-CSF correlations were observed for CRP and IL-6, plasma levels of all three markers (CRP, IL-6, and YKL-40) increased from PREOP to PO1MO, and CSF levels of only CRP increased between the two time points. Our identification of potential promising plasma markers of inflammation in the CNS may facilitate the early identification of patients at greatest risk for neuroinflammation and its associated adverse cognitive outcomes.

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