Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex
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...
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Frontiers Media S.A.
2022-01-01
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| Series: | Frontiers in Physiology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fphys.2021.749255/full |
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| author | Hironori Watanabe Shotaro Saito Takuro Washio Takuro Washio Damian Miles Bailey Damian Miles Bailey Shigehiko Ogoh Shigehiko Ogoh |
| author_facet | Hironori Watanabe Shotaro Saito Takuro Washio Takuro Washio Damian Miles Bailey Damian Miles Bailey Shigehiko Ogoh Shigehiko Ogoh |
| author_sort | Hironori Watanabe |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-11T20:29:05Z |
| format | Article |
| id | doaj.art-4547b08ef6b1458891b1b542e1122354 |
| institution | Directory Open Access Journal |
| issn | 1664-042X |
| language | English |
| last_indexed | 2024-04-11T20:29:05Z |
| publishDate | 2022-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Physiology |
| spelling | doaj.art-4547b08ef6b1458891b1b542e11223542022-12-22T04:04:33ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2022-01-011210.3389/fphys.2021.749255749255Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory ChemoreflexHironori Watanabe0Shotaro Saito1Takuro Washio2Takuro Washio3Damian Miles Bailey4Damian Miles Bailey5Shigehiko Ogoh6Shigehiko Ogoh7Department of Biomedical Engineering, Toyo University, Kawagoe, JapanDepartment of Biomedical Engineering, Toyo University, Kawagoe, JapanDepartment of Biomedical Engineering, Toyo University, Kawagoe, JapanResearch Fellow of Japan Society for the Promotion of Science, Tokyo, JapanResearch Fellow of Japan Society for the Promotion of Science, Tokyo, JapanNeurovascular Research Laboratory, University of South Wales, Pontypridd, United KingdomDepartment of Biomedical Engineering, Toyo University, Kawagoe, JapanNeurovascular Research Laboratory, University of South Wales, Pontypridd, United KingdomCerebrovascular 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.https://www.frontiersin.org/articles/10.3389/fphys.2021.749255/fullanterior cerebral blood flowposterior cerebral blood flowrespiratory chemoreflexhead-up tilthypercapnia |
| spellingShingle | Hironori Watanabe Shotaro Saito Takuro Washio Takuro Washio Damian Miles Bailey Damian Miles Bailey Shigehiko Ogoh Shigehiko Ogoh Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex Frontiers in Physiology anterior cerebral blood flow posterior cerebral blood flow respiratory chemoreflex head-up tilt hypercapnia |
| title | Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex |
| title_full | Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex |
| title_fullStr | Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex |
| title_full_unstemmed | Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex |
| title_short | Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex |
| title_sort | acute gravitational stress selectively impairs dynamic cerebrovascular reactivity in the anterior circulation independent of changes to the central respiratory chemoreflex |
| topic | anterior cerebral blood flow posterior cerebral blood flow respiratory chemoreflex head-up tilt hypercapnia |
| url | https://www.frontiersin.org/articles/10.3389/fphys.2021.749255/full |
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