Autonomic Neural Control of Dynamic Cerebral Autoregulation in Humans

Zhang, Rong; Zuckerman, Julie H.; Iwasaki, Katsurô; Wilson, Thad E.; Crandall, Craig G.; Levine, Benjamin D.

doi:10.1161/01.cir.0000031798.07790.fe

Cited by 402 publications

(394 citation statements)

References 47 publications

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“…1). The absence and/or attenuation of the heart rate response demonstrated the efficacy of ganglionic blockade (19,24,25). A minimum of 2 min elapsed between successive VMs.…”

Section: Subjectsmentioning

confidence: 97%

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Evidence of a myogenic response in vasomotor control of forearm and palm cutaneous microcirculations

Durand

Zhang²,

Cui

et al. 2004

Journal of Applied Physiology

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Evidence of a myogenic response in vasomotor control of forearm and palm cutaneous microcirculations. J Appl Physiol 97: 535-539, 2004. First published April 16, 2004 10.1152/japplphysiol.01299.2003.-Previous investigations of autoregulatory mechanisms in the control of skin blood flow suffer from the possibility of interfering effects of the autonomic nervous system. To address this question, in 11 subjects cutaneous vascular responses were measured during acute changes in perfusion pressure (using Valsalva maneuver; VM) before and after ganglionic blockade via systemic trimethaphan infusion. Cutaneous vascular conductance at baseline (CVC base) and during the last 5 s of the VM (CVC VM) were measured from forearm (nonglabrous) and palm (glabrous) skin. During the VM without ganglionic blockade, compared with CVCbase, CVCVM decreased significantly at the palm [0.79 Ϯ 0.17 to 0.55 Ϯ 0.17 arbitrary units (AU)/mmHg; P ϭ 0.002] but was unchanged at the forearm (0.13 Ϯ 0.02 to 0.16 Ϯ 0.02 AU/mmHg; P ϭ 0.50). After ganglionic blockade, VM induced pronounced decreases in perfusion pressure, which resulted in significant increases in CVC VM at both forearm (0.19 Ϯ 0.03 to 0.31 Ϯ 0.07 AU/mmHg; P ϭ 0.008) and palm (1.84 Ϯ 0.29 to 2.76 Ϯ 0.63 AU/mmHg; P ϭ 0.003) sites. These results suggest that, devoid of autonomic control, both glabrous and nonglabrous skin are capable of exhibiting vasomotor autoregulation during pronounced reductions in perfusion pressure. autoregulation; skin blood flow; Valsalva maneuver CUTANEOUS TISSUE HAS RELATIVELY low metabolic requirements, and control of skin blood flow is primary influenced by thermal factors (e.g., local and internal temperatures). Skin blood flow can also be modulated by nonneurally mediated events, one of which may be vascular cutaneous autoregulation. Vascular autoregulation serves to maintain blood flow and nutrient supply when perfusion pressure is altered. In addition, autoregulatory responses attenuate large changes in capillary pressure that otherwise would occur during changes in perfusion pressure (15).Cutaneous blood flow during normothermic conditions is in excess of that required to provide for its metabolic demand. Given this, the requirement to autoregulate blood flow through this vascular bed during relatively small changes in perfusion pressure would be less critical relative to other vascular beds. Such a response is likely advantageous given that precise autoregulation of cutaneous vasculature would oppose thermally induced cutaneous vasoconstriction and vasodilation, which are necessary to maintain temperature homeostasis (21).The venoarteriolar response is an example of a vascular autoregulatory mechanism that has been identified and widely investigated in human skin (3,7,9,13,23). However, the stimulus for this response is a change in venous pressure regardless of whether perfusion pressure changes or remains constant. This response also requires an intact local neural network (3,7,10,13,23), which is in contrast to traditional myogenic vascular autor...

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“…1). The absence and/or attenuation of the heart rate response demonstrated the efficacy of ganglionic blockade (19,24,25). A minimum of 2 min elapsed between successive VMs.…”

Section: Subjectsmentioning

confidence: 97%

“…This project was a component of a larger project of which data have been previously presented (24,25).…”

Section: Disclosuresmentioning

confidence: 99%

Evidence of a myogenic response in vasomotor control of forearm and palm cutaneous microcirculations

Durand

Zhang²,

Cui

et al. 2004

Journal of Applied Physiology

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“…Acute exposure to isocapnic hypoxia leads to dilation of small pial cerebral vessels (12), also accompanied with an increase in peripheral vasoconstrictor sympathetic outflow (19,25,38). Previous investigations have implicated a strong neural influence on dCA, given that eliminating neural control of cerebral vessels with a ganglion blockade impairs indexes of dCA (3,40). Also, reducing cerebral vessel tone with hypercapnia reduces the effectiveness of dCA (1,33), suggesting that adequate cerebral vessel tone is required for effective dCA.…”

Section: Ca In Hypoxiamentioning

confidence: 99%

Dynamic cerebral autoregulation during and following acute hypoxia: role of carbon dioxide

Querido

Ainslie

Foster

et al. 2013

Journal of Applied Physiology

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Querido JS, Ainslie PN, Foster GE, Henderson WR, Halliwill JR, Ayas NT, Sheel AW. Dynamic cerebral autoregulation during and following acute hypoxia: role of carbon dioxide. J Appl Physiol 114: 1183-1190, 2013. First published March 7, 2013 doi:10.1152/japplphysiol.00024.2013.-Previous research has shown an inconsistent effect of hypoxia on dynamic cerebral autoregulation (dCA), which may be explained by concurrent CO2 control. To test the hypothesis that hypoxic dCA is mediated by CO2, we assessed dCA (transcranial Doppler) during and following acute normobaric isocapnic and poikilocapnic hypoxic exposures. On 2 separate days, the squat-stand maneuver was used to determine dCA in healthy subjects (n ϭ 8; 3 women) in isocapnic and poikilocapnic hypoxia exposures (end-tidal oxygen pressure 50 Torr for 20 min). In isocapnic hypoxia, the amplitude of the cerebral blood flow response to increases and decreases in mean arterial blood pressure were elevated (i.e., increases in gain of ϩ35 and ϩ28%, respectively; P Ͻ 0.05). However, dCA gain to increases in pressure was reduced compared with baseline (Ϫ32%, P Ͻ 0.05) following the isocapnic hypoxia exposure. Similarly, intravenous bolus injections of sodium nitroprusside and phenylephrine in a separate group of subjects (n ϭ 8; 4 women) also demonstrated a reduction in dCA gain to hypertension following isocapnic hypoxia. In contrast, dCA gain with the squat-stand maneuver did not significantly change from baseline during or following poikilocapnic hypoxia (P Ͼ 0.05). Our results demonstrate that dCA impairment in isocapnic hypoxia can be prevented with hypocapnia, and highlight the integrated nature of hypoxic cerebrovascular control, which is under strong CO2 influence. autonomic control; cerebral autoregulation; hypoxia; hypocapnia CEREBRAL AUTOREGULATION (CA) refers to the physiological mechanisms that maintain blood flow constant during steadystate (static CA) and abrupt [dynamic CA (dCA)] changes in blood pressure. The mechanisms of CA are complex and incompletely understood, but likely rely on a combination and interaction of myogenic, neural, endothelial, and metabolic factors (1, 32). Although recently challenged in both healthy humans (18) and patients (13), the conventional model of static CA proposes that cerebral blood flow (CBF) is independent of steady-state changes in mean arterial pressure (MAP) between ϳ50 and 160 mmHg (17). In contrast, dCA responds to sudden changes in blood pressure and is frequently active throughout a typical day, such as during rapid adjustments in posture. Early methods of dCA assessment in humans often included an abrupt decrease in blood pressure with rapid thigh-cuff deflation (1), whereas later assessments focused on transfer function analysis of spontaneous oscillations in blood pressure and CBF over both time and frequency domains (39). Although these methods have the advantage of being noninvasive and easily administered, they do not fully characterize dCA. Specifically, these methods do not differentiate the dCA respon...

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“…Состо-яние мозгового кровотока модулируется не только церебральной ауторегуляцией, но и вегетативной нервной системой и артериальным барорефлектор-но-опосредованным контролем в большом круге кровообращения [41]. В ответ на симпатическую ак-тивацию наблюдается вазоконстрикция [42,43]. Це-ребральные механизмы ауторегуляции способны компенсировать потребление кислорода [44], одна-ко повторные эпизоды гипоперфузии приводят к истощению компенсаторных возможностей.…”

Section: патогенез ог при дтлunclassified

Orthostatic hypotension in dementia with Lewy bodies

Чимагомедова¹,

Левин²

2016

Z. nevrol. psikhiatr. im. S.S. Korsakova

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ГБОУ ДПО «Российская медицинская академия последипломного образования», Москва, Россия В обзоре рассматриваются особенности проявления ортостатической гипотензии при деменции с тельцами Леви и методы ее диагностики. Ранняя диагностика данных нарушений позволит предотвратить такие нежелательные последствия, как падения и обмороки, улучшить повседневную деятельность и повысить качество жизни пациентов. анализируются современные подходы к коррекции данного состояния. The features of orthostatic hypotension in patients with dementia with Lewy bodies are considered. The early diagnosis of these disorders could prevent adverse conditions (falls and syncopes), improve activities of daily living and quality-of-life. Current approaches to treatment of orthostatic hypotension are analyzed.

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Autonomic Neural Control of Dynamic Cerebral Autoregulation in Humans

Cited by 402 publications

References 47 publications

Evidence of a myogenic response in vasomotor control of forearm and palm cutaneous microcirculations

Evidence of a myogenic response in vasomotor control of forearm and palm cutaneous microcirculations

Dynamic cerebral autoregulation during and following acute hypoxia: role of carbon dioxide

Orthostatic hypotension in dementia with Lewy bodies

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