Baroreceptor influence on postural changes in blood pressure and carotid blood flow

1963 ◽  
Vol 205 (2) ◽  
pp. 360-364 ◽  
Author(s):  
Francis L. Abel ◽  
John H. Pierce ◽  
Warren G. Guntheroth
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Sinus ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Carotid Blood Flow ◽  
Postural Changes ◽  
Nembutal Anesthesia

The effects of 30° head-down and head-up tilting on mean systemic blood pressure, carotid blood flow, and heart rate were studied in 16 dogs under morphine and Nembutal anesthesia. The tilting procedure was further repeated after denervation of the carotid sinus and aortic arch baroreceptors and after administration of a dihydrogenated ergot alkaloid mixture (Hydergine). The results indicate that the drop in pressure in the head-down position is primarily due to baroreceptor activity and that the baroreceptors are necessary for compensatory vasoconstriction on head-up tilting. Carotid blood flow decreased in both tilted positions in the control animals; the possible relationship to cerebral blood flow is discussed.

The Postural Autonomic Regulation of Pulpal Blood Flow

2012 ◽  
Vol 92 (2) ◽  
pp. 156-160 ◽  
Author(s):  
O. Ajcharanukul ◽  
E. Chunhacheevachaloke ◽  
P. Vorachart ◽  
W. Chidchuangchai
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Venous Blood ◽  
Systemic Blood Pressure ◽  
Blood Pressure Monitor ◽  
Pressure Monitor ◽  
Systemic Blood ◽  
Pulpal Blood Flow ◽  
Postural Changes

Evidence suggests that postural changes in systemic blood pressure may significantly affect blood flow in the dental pulp. This in vivo study examined the responses of pulpal perfusion, systemic blood pressure, and heart rate to postural changes in humans. The experiments were done on 21 premolars in 16 participants aged 20-31 yrs. Pulpal blood flow recordings were measured by means of a laser Doppler Flowmeter. A blood pressure monitor was used to record blood pressure and heart rate. All measurements were simultaneously recorded for 1 min, 5 min after participants made postural changes. Changing from supine to standing caused a significant reduction in pulpal perfusion, while heart rate and diastolic blood pressure increased significantly. A significant non-linear relationship was found between percentage changes in pulpal perfusion and heart rate resulting from standing up. We speculate that when patients arise from the supine position, the shift in venous blood to the legs transiently (2-10 sec) lowers venous return and cardiac output, causing less inhibition of the vasomotor center, which, in turn, results in increased heart rate and blood pressure, but a decrease in pulpal blood flow. These results suggest that pulpal blood flow is affected by postural change, presumably via the autonomic nervous system.

scholarly journals Possible Neuroprotective Properties of Flunarizine Infused after Asphyxia in Fetal Lambs Are Not Explained by Effects on Cerebral Blood Flow or Systemic Blood Pressure

1993 ◽  
Vol 34 (3) ◽  
pp. 379-384 ◽  
Author(s):  
Harmen H De Haan ◽  
Jos L H Van Reempts ◽  
Marcel Borgers ◽  
Jelte De Haan ◽  
Johan S H Vles ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Systemic Blood Pressure ◽  
Systemic Blood

Brain adenosine production in rat during sustained alteration in systemic blood pressure

1980 ◽  
Vol 239 (5) ◽  
pp. H636-H641 ◽  
Author(s):  
H. R. Winn ◽  
J. E. Welsh ◽  
R. Rubio ◽  
R. M. Berne
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Autoregulation ◽  
Adenine Nucleotides ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Arterial Blood ◽  
Adenosine Concentration ◽  
Severe Hypotension

Brain production of adenosine and its metabolites, inosine and hypoxanthine was determined in 46 rats during sustained (5 min) reduction in mean arterial blood pressure (MABP) caused by hemorrhage. Also measured were ATP, ADP, AMP, phosphocreatine (PCr), and lactate. Brain tissue was obtained by the freeze-blowing technique. Ventilation was controlled to maintain constant arterial O2 tension, CO2 tension, and pH. When MABP was decreased from 135 + 3 (SE) mmHg to 72 +/- 2 mmHg, within the range of cerebral autoregulation, brain adenosine concentration doubled from 0.55 +/- 0.12 to 1.16 +/- 0.13 nmol/g (P < 0.015). Unlike the changes in adenosine concentrations, adenine nucleotides and PCr remained stable. Lactate varied inversely with MABP. With moderate to severe hypotension (MABP = 45 +/- 3 mmHg), adenosine levels increased almost sixfold. The increment in brain adenosine concentration within the autoregulatory range supports a role for this potent dilator of pial vessels in the regulation of cerebral blood flow.

scholarly journals Animal model of assessing cerebrovascular functional reserve by imaging photoplethysmography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Oleg V. Mamontov ◽  
Alexey Y. Sokolov ◽  
Maxim A. Volynsky ◽  
Anastasija V. Osipchuk ◽  
Valery V. Zaytsev ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Animal Model ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Systemic Blood Pressure ◽  
Functional Reserve ◽  
Systemic Blood ◽  
Flow Reserve ◽  
Custom Made ◽  
End Tidal

Abstract Assessment of the cerebral blood-flow-reserve in patients with cerebrovascular diseases is extremely important in terms of making prognosis, determining treatment tactics, and controlling the revascularization outcome in the case of reconstructive interventions on the brain vessels. However, there is no easy-to-use, contactless method for either assessing the functional reserve of the cortical vascular network or intraoperative monitoring of surgical intervention. Our study aims to demonstrate feasibility of green-light imaging photoplethysmography (iPPG) to estimate cerebrovascular functional reserve in animal model of craniosurgical intervention. Custom-made iPPG system was exploited to visualize intracranial vessels in anesthetized Wistar rats (n = 15). Video frames of rat’s cortex were recorded concurrently with systemic blood pressure, end-tidal CO2, and electrocardiogram. We found that injection of dorzolamide (carbonic-anhydrase inhibitor) significantly increased the blood-pulsations amplitude in all animals by 35 ± 19% (p < 0.001). Such an increase negatively correlated with significant decrease in end-tidal CO2 by 32 ± 7% (p < 0.001). It is noteworthy that the dorzolamide injection did not lead to significant changes in systemic blood pressure. Concluding, pulsations amplitude is a marker of the vascular tone that can be used to evaluate the functional cerebrovascular reserve. Imaging PPG is a simple and convenient method to assess cerebral blood flow, including during various neurosurgical interventions.

scholarly journals The scale of cerebral ischemia thresholds in rats

2018 ◽  
pp. 128-129
Author(s):  
В.В. Александрин
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Ischemia ◽  
Blood Loss ◽  
Threshold Value ◽  
Systemic Blood Pressure ◽  
Male Rats ◽  
Systemic Blood ◽  
Doppler Flowmeter

Прогноз и тактика лечения инсульта зависят от его тяжести, которая задается достигнутым ишемическом порогом. Исследование механизмов формирования ишемических порогов является актуальной патофизиологической задачей. Целью настоящего исследования явилось получение данных для построения шкалы порогов ишемии мозга у крыс. Эксперименты проводили на наркотизированных беспородных крысах-самцах. Мозговой кровоток регистрировали лазерным допплеровским флоуметром ЛАКК-02 (Лазма, Россия). Контролируемую кровопотерю осуществляли через бедренную артерию. Фиксировали системное артериальное давление (АД), при котором в условиях медленной кровопотери регистрировалось пороговое значение мозгового кровотока. На основании полученных данных строилась шкала: системное АД - кровоток - пороги ишемии мозга. Prognosis and treatment of stroke depend on its severity, which is defined by the attained ischemic threshold. Studying the mechanisms underlying the formation of ischemic thresholds is an urgent pathophysiological task. The aim of this study was to obtain data for constructing a scale of cerebral ischemia thresholds in rats. Experiments were carried out on anesthetized mongrel male rats. Cerebral blood flow was recorded with a laser Doppler flowmeter, LAKK-02 (Lazma, Russia). Controlled blood loss was performed through the femoral artery. Systemic blood pressure, at which the threshold value of cerebral blood flow was attained, was recorded under the conditions of slow blood loss. Based on the obtained data the systemic blood pressure - blood flow - thresholds of cerebral ischemia scale was constructed.

Systemic Blood Pressure and Cerebral Blood Flow Velocity During Carotid Surgery

1999 ◽  
Vol 47 (06) ◽  
pp. 381-385 ◽  
Author(s):  
G. Grubhofer ◽  
A. Lassnigg ◽  
T. Pernerstorfer ◽  
O. Ipsiroglu ◽  
M. Czerny ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Systemic Blood Pressure ◽  
Carotid Surgery ◽  
Systemic Blood
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