scholarly journals Onset responses of ventilation and cerebral blood flow to hypercapnia in humans: rest and exercise

2009 ◽  
Vol 106 (3) ◽  
pp. 880-886 ◽  
Author(s):  
Shigehiko Ogoh ◽  
Philip N. Ainslie ◽  
Tadayoshi Miyamoto
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebrovascular Reactivity ◽  
Ph Homeostasis ◽  
Text Response ◽  
Respiratory Chemoreflex ◽  
Exponential Regression Model ◽  
Cerebral Vasodilation ◽  
Onset Response ◽  
Onset Responses

The respiratory and cerebrovascular reactivity to changes in arterial Pco2 ([Formula: see text]) is an important mechanism that maintains CO2 or pH homeostasis in the brain. It remains unclear, however, how cerebrovascular CO2 reactivity might influence the respiratory chemoreflex. The purpose of the present study was therefore to examine the interaction between onset responses of the respiratory chemoreflex and middle cerebral artery (MCA) mean blood velocity ( Vmean) to hypercapnia (5.0% CO2-40% O2-balance N2) at rest and during dynamic exercise (∼1.0 l/min O2 consumption). Each onset response was evaluated using a single-exponential regression model consisting of the response time latency [CO2-response delay ( t0)] and time constant (τ). At rest, t0 and τ data indicated that the MCA Vmean onset response was faster than the ventilatory (V̇e) response ( P < 0.001). In contrast, during exercise, t0 of V̇e and MCA Vmean onset responses were decreased. In addition, despite the enhanced [Formula: see text] response to CO2 administration ( P = 0.014), τ of MCA Vmean tended to increase during exercise ( P = 0.054), whereas τ of V̇e decreased ( P = 0.015). These findings indicate that 1) at rest, faster washout of CO2 via cerebral vasodilation results in a reduced activation of the central chemoreflex and subsequent reduced V̇e onset response, and 2) during exercise, despite higher rates of increasing [Formula: see text], the lack of change in the onset response of cerebral blood flow and reduced washout of CO2 may act to augment the V̇e onset response.

scholarly journals Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex

2022 ◽  
Vol 12 ◽  
Author(s):  
Hironori Watanabe ◽  
Shotaro Saito ◽  
Takuro Washio ◽  
Damian Miles Bailey ◽  
Shigehiko Ogoh
Keyword(s):  
Pulmonary Ventilation ◽  
Cerebrovascular Reactivity ◽  
Ph Homeostasis ◽  
Anterior Circulation ◽  
Gravitational Stress ◽  
Head Up Tilt ◽  
Respiratory Chemoreflex ◽  
Time Latency ◽  
Exponential Regression Model ◽  
Onset Response

Cerebrovascular reactivity (CVR) to changes in the partial pressure of arterial carbon dioxide (PaCO2) is an important mechanism that maintains CO2 or pH homeostasis in the brain. To what extent this is influenced by gravitational stress and corresponding implications for the regulation of cerebral blood flow (CBF) remain unclear. The present study examined the onset responses of pulmonary ventilation (V̇E) and anterior middle (MCA) and posterior (PCA) cerebral artery mean blood velocity (Vmean) responses to acute hypercapnia (5% CO2) to infer dynamic changes in the central respiratory chemoreflex and cerebrovascular reactivity (CVR), in supine and 50° head-up tilt (HUT) positions. Each onset response was evaluated using a single-exponential regression model consisting of the response time latency [CO2-response delay (t0)] and time constant (τ). Onset response of V̇E and PCA Vmean to changes in CO2 was unchanged during 50° HUT compared with supine (τ: V̇E, p = 0.707; PCA Vmean, p = 0.071 vs. supine) but the MCA Vmean onset response was faster during supine than during 50° HUT (τ: p = 0.003 vs. supine). These data indicate that gravitational stress selectively impaired dynamic CVR in the anterior cerebral circulation, whereas the posterior circulation was preserved, independent of any changes to the central respiratory chemoreflex. Collectively, our findings highlight the regional heterogeneity underlying CBF regulation that may have translational implications for the microgravity (and hypercapnia) associated with deep-space flight notwithstanding terrestrial orthostatic diseases that have been linked to accelerated cognitive decline and neurodegeneration.

scholarly journals Transcranial Doppler Evaluation of the Cerebral Vasculature in Women Patients who Have Migraine with Aura

Pain Medicine ◽  
2020 ◽  
Vol 21 (11) ◽  
pp. 3012-3017
Author(s):  
Igor Petrušić ◽  
Ana Podgorac ◽  
Aleksandra Radojičić ◽  
Jasna Zidverc-Trajković
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Migraine With Aura ◽  
Transcranial Doppler ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Transcranial Doppler Sonography ◽  
Cerebrovascular Reactivity ◽  
Breath Holding ◽  
Left And Right

Abstract Background Previous studies suggest that increased cerebrovascular reactivity might be a feature of patients who have migraine with aura (MwA). The correlation between the clinical presentation of migraine with aura and transcranial Doppler parameters remains unclear. Objective The main aim of this study was to explore cerebral blood flow, vascular resistance, and cerebrovascular reactivity in women MwA. Also, the relationships between hemodynamic conditions and aura characteristics are examined. Design Cross-sectional study. Setting Headache Center, Neurology Clinic, Clinical Center of Serbia. Subjects Fifty-four women MwA and 49 healthy controls (HCs). Methods Transcranial Doppler sonography examination was used to determine blood flow mean velocity (MV) and pulsatility index (PI), as well as breath-holding index (BHI), in 15 arterial segments comprising the circle of Willis. Results A total of 54 women MwA and 49 HCs were studied. The PIs of all segments of the left and right middle cerebral arteries and the left and right anterior cerebral arteries were significantly higher in MwA with regards to HCs. Also, both the left and right BHIs were significantly higher in MwA than HCs. In addition, MVs of the right vertebral artery and the first segment of the basilar artery were significantly lower in MwA than HCs. Longer duration of migraine aura showed a weak negative correlation with the PI of the left posterior cerebral artery. Conclusions Our findings suggest increased vessel pulsatility, abnormal cerebrovascular reactivity, and decreased cerebral blood flow velocity in several arterial segments of the Willis circle in women MwA.

scholarly journals Higher Aortic Stiffness Is Related to Lower Cerebral Blood Flow and Preserved Cerebrovascular Reactivity in Older Adults

Circulation ◽  
2018 ◽  
Vol 138 (18) ◽  
pp. 1951-1962 ◽  
Author(s):  
Angela L. Jefferson ◽  
Francis E. Cambronero ◽  
Dandan Liu ◽  
Elizabeth E. Moore ◽  
Jacquelyn E. Neal ◽  
...  
Keyword(s):  
Older Adults ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Aortic Stiffness ◽  
Cerebrovascular Reactivity

scholarly journals Effects of GV14 Acupuncture on Cerebral Blood Flow Velocity in the Basilar and Middle Cerebral Arteries and CO2 Reactivity during Hypercapnia in Normal Individuals

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hyun Ku Lee ◽  
Sang-Kwan Moon ◽  
Chul Jin ◽  
Seung-Yeon Cho ◽  
Seong-Uk Park ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Transcranial Doppler Sonography ◽  
Cerebrovascular Reactivity ◽  
Acupuncture Points ◽  
Co2 Reactivity ◽  
Middle Cerebral Arteries

The Governing Vessel 14 (GV14) (Dazhui) is one of the acupuncture points referred to as “seven acupoints for stroke.” Nevertheless, there is a scarcity of research on the effects of acupuncture treatment at GV14. This study investigated the effects of acupuncture at GV14 on cerebral blood flow (CBF), especially that in the basilar artery (BA) and the middle cerebral arteries (MCA). Sixteen healthy men aged 20 to 29 years were enrolled in this study. CBF velocity and cerebrovascular reactivity (CVR) were measured using transcranial Doppler sonography (TCD). The following were assessed: closed circuit rebreathing- (CCR-) induced carbon dioxide (CO2) reactivity, modified blood flow velocity at 40 mmHg (CV40) on BA and MCAs, blood pressure (BP), and heart rate (HR). Observed results were obtained after comparison with the baseline evaluation. Statistically significant elevations in CO2 reactivity were recorded in the BA (3.28 to 4.70, p < 0.001 ) and MCAs (right: 3.81 to 5.25, p = 0.001 ; left: 3.84 to 5.12, p = 0.005 ) after acupuncture at GV14. The CV40 increased statistically significantly only in the BA (45.49 to 50.41, p = 0.003 ). No change was observed in BP (106.83 to 107.08 (mmHg), p = 0.335 ) and HR (77 to 75 (bpm), p = 0.431 ). Acupuncture at GV14 improved CBF velocity. These results could be explained by the regulation of endothelium-dependent vessel dilation effected by acupuncture. This trial is registered with Korean Clinical Trial Registry (http://cris.nih.go.kr; registration number: KCT0004787).

scholarly journals Cardiorespiratory fitness is associated with increased middle cerebral arterial compliance and decreased cerebral blood flow in young healthy adults: A pulsed ASL MRI study

2019 ◽  
Vol 40 (9) ◽  
pp. 1879-1889 ◽  
Author(s):  
Hannah V Furby ◽  
Esther AH Warnert ◽  
Christopher J Marley ◽  
Damian M Bailey ◽  
Richard G Wise
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cardiorespiratory Fitness ◽  
Grey Matter ◽  
Arterial Compliance ◽  
Cerebral Arteries ◽  
Early Adulthood ◽  
Cerebrovascular Reactivity ◽  
Beneficial Effects ◽  
Cerebral Arterial Compliance

Cardiorespiratory fitness is thought to have beneficial effects on systemic vascular health, in part, by decreasing arterial stiffness. However, in the absence of non-invasive methods, it remains unknown whether this effect extends to the cerebrovasculature. The present study uses a novel pulsed arterial spin labelling (pASL) technique to explore the relationship between cardiorespiratory fitness and arterial compliance of the middle cerebral arteries (MCAC). Other markers of cerebrovascular health, including resting cerebral blood flow (CBF) and cerebrovascular reactivity to CO2 (CVRCO2) were also investigated. Eleven healthy males aged 21 ± 2 years with varying levels of cardiorespiratory fitness (maximal oxygen uptake ([Formula: see text]O2MAX) 38–76 ml/min/kg) underwent MRI scanning at 3 Tesla. Higher [Formula: see text]O2MAX was associated with greater MCAC (R2 = 0.64, p < 0.01) and lower resting grey matter CBF (R2 = 0.75, p < 0.01). However, [Formula: see text]O2MAX was not predictive of global grey matter BOLD-based CVR (R2 = 0.47, p = 0.17) or CBF-based CVR (R2 = 0.19, p = 0.21). The current experiment builds upon the established benefits of exercise on arterial compliance in the systemic vasculature, by showing that increased cardiorespiratory fitness is associated with greater cerebral arterial compliance in early adulthood.

Binge alcohol exposure in the second trimester attenuates fetal cerebral blood flow response to hypoxia

2007 ◽  
Vol 102 (3) ◽  
pp. 972-977 ◽  
Author(s):  
Dennis E. Mayock ◽  
Dana Ness ◽  
Robin L. Mondares ◽  
Christine A. Gleason
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Damage ◽  
Alcohol Exposure ◽  
Oxygen Metabolism ◽  
Developed Countries ◽  
Cerebrovascular Reactivity ◽  
Second Trimester ◽  
Fetal Alcohol Exposure ◽  
Fetal Alcohol

Alcohol is detrimental to the developing brain and remains the leading cause of mental retardation in developed countries. The mechanism of alcohol brain damage remains elusive. Studies of neurological problems in adults have focused on alcohol's cerebrovascular effects, because alcoholism is a major risk factor for stroke and cerebrovascular injuries. However, few studies have examined similar cerebrovascular effects of fetal alcohol exposure. We examined the effect of chronic binge alcohol exposure during the second trimester on fetal cerebrovascular and metabolic responses to hypoxia in near-term sheep and tested the hypothesis that fetal alcohol exposure would attenuate cerebrovascular dilation to hypoxia. Pregnant ewes were infused with alcohol (1.5 g/kg) or saline intravenously at 60–90 days of gestation (full term = 150 days). At 125 days of gestation, we measured fetal cerebral blood flow (CBF) and oxygen metabolism at baseline and during hypoxia. Maternal blood alcohol averaged 214 ± 5.9 mg/dl immediately after the 1.5-h infusion, with similar values throughout the month of infusion. Hypoxia resulted in a robust increase in CBF in saline-infused fetuses. However, the CBF response to hypoxia in fetuses chronically exposed to alcohol was significantly attenuated. Cerebral oxygen delivery decreased in both groups of fetuses during hypoxia but to a greater degree in the alcohol-exposed fetuses. Prenatal alcohol exposure during the second trimester attenuates cerebrovascular responses to hypoxia in the third trimester. Altered cerebrovascular reactivity might be one mechanism for alcohol-related brain damage and might set the stage for further brain injury if a hypoxic insult occurs.

Comparison of cerebrovascular effects of intravenous cocaine injection in fetal, newborn, and adult sheep

2000 ◽  
Vol 279 (1) ◽  
pp. H1-H6 ◽  
Author(s):  
Roderick Robinson ◽  
Hiroki Iida ◽  
Thomas P. O'Brien ◽  
Maria A. Pane ◽  
Richard J. Traystman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Species Differences ◽  
Developmental Differences ◽  
Metabolic Responses ◽  
Cerebral Vasoconstriction ◽  
Arterial Blood ◽  
Cerebral Vasodilation ◽  
Cerebral Vascular Resistance ◽  
Intravenous Cocaine

Cocaine may cause stroke, intracranial hemorrhage, seizures, and neurobehavioral abnormalities in fetuses, newborns, and adults, and there could be developmental and/or species differences in mechanisms for these cocaine-induced cerebrovascular effects. To evaluate developmental differences in responses to cocaine, we compared the cerebrovascular and metabolic responses to a 2 mg/kg iv cocaine dose in unanesthetized fetal ( n = 8, previously reported, direct fetal injection), newborn ( n = 6), and adult ( n = 12) sheep. We measured cerebral blood flow, mean arterial blood pressure, and arterial and venous O2content, and we calculated cerebral O2consumption and cerebral vascular resistance at baseline and at 30 s and at 5, 15, and 60 min after cocaine injection. Cerebral blood flow increased 5 min after injection in the fetus and newborn, but not until 15 min in the adult. In the fetus, cocaine caused a transient cerebral vasoconstriction at 30 s; in all three groups, cocaine caused cerebral vasodilation, which was delayed in the adult. Cerebral metabolic O2consumption increased 5 min after injection in the fetus and newborn, but not until 15 min after injection in the adult. Arterial O2content decreased 5 min after injection in the fetus and 15 min after injection in the adult. We speculate that clinical differences in response to cocaine injection may be explained, in part, by these developmental differences in the cerebrovascular and metabolic responses to cocaine.

scholarly journals The Effect of Black Tea and Caffeine on Regional Cerebral Blood Flow Measured with Arterial Spin Labeling

2013 ◽  
Vol 33 (6) ◽  
pp. 963-968 ◽  
Author(s):  
Rishma Vidyasagar ◽  
Arno Greyling ◽  
Richard Draijer ◽  
Douglas R Corfield ◽  
Laura M Parkes
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Vascular Function ◽  
Black Tea ◽  
Cerebrovascular Reactivity ◽  
Controlled Study ◽  
Brain Vasculature ◽  
Espresso Coffee ◽  
Magnetic Resonance Imaging Mri ◽  
Double Blinded

Black tea consumption has been shown to improve peripheral vascular function. Its effect on brain vasculature is unknown, though tea contains small amounts of caffeine, a psychoactive substance known to influence cerebral blood flow (CBF). We investigated the effects on CBF due to the intake of tea components in 20 healthy men in a double-blinded, randomized, placebo-controlled study. On separate days, subjects received a single dose of 184 mg caffeine (equivalent to one strong espresso coffee), 2,820 mg black tea solids containing 184 mg caffeine (equivalent to 6 cups of tea), 2,820 mg decaffeinated black tea solids, or placebo. The CBF and cerebrovascular reactivity (CVR) to hypercapnia were measured with arterial spin labeled magnetic resonance imaging (MRI) before and 2 hours after administration. We found a significant global reduction with caffeine (20%) and tea (21%) in gray matter CBF, with no effect of decaffeinated tea, suggesting that only caffeine influences CBF acutely. Voxelwise analysis revealed the effect of caffeine to be regionally specific. None of the interventions had an effect on CVR. Additional research is required to conclude on the physiologic relevance of these findings and the chronic effects of caffeine and tea intake on CBF.

scholarly journals The Contribution of Arterial Blood Gases in Cerebral Blood Flow Regulation and Fuel Utilization in Man at High Altitude

2015 ◽  
Vol 35 (5) ◽  
pp. 873-881 ◽  
Author(s):  
Christopher K Willie ◽  
David B MacLeod ◽  
Kurt J Smith ◽  
Nia C Lewis ◽  
Glen E Foster ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
High Altitude ◽  
Cerebral Metabolism ◽  
Venous Blood ◽  
Blood Gases ◽  
Cerebrovascular Reactivity ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
Cerebrovascular Function

The effects of partial acclimatization to high altitude (HA; 5,050 m) on cerebral metabolism and cerebrovascular function have not been characterized. We hypothesized (1) increased cerebrovascular reactivity (CVR) at HA; and (2) that CO2 would affect cerebral metabolism more than hypoxia. PaO2 and PaCO2 were manipulated at sea level (SL) to simulate HA exposure, and at HA, SL blood gases were simulated; CVR was assessed at both altitudes. Arterial–jugular venous differences were measured to calculate cerebral metabolic rates and cerebral blood flow (CBF). We observed that (1) partial acclimatization yields a steeper CO2-H+ relation in both arterial and jugular venous blood; yet (2) CVR did not change, despite (3) mean arterial pressure (MAP)-CO2 reactivity being doubled at HA, thus indicating effective cerebral autoregulation. (4) At SL hypoxia increased CBF, and restoration of oxygen at HA reduced CBF, but neither had any effect on cerebral metabolism. Acclimatization resets the cerebrovasculature to chronic hypocapnia.

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