EFFECTS OF HEART RATE AND ARTERIAL BLOOD PRESSURE ON CORONARY COLLATERAL BLOOD FLOW IN DOGS

1. The effects of l-arginine on systemic and renal haemodynamics were investigated in conscious dogs. l-Arginine was administered intravenously at doses of 15 and 75 μmol min−1 kg−1 for 20 min. 2. Mean arterial blood pressure, heart rate and cardiac output were not changed significantly by l-arginine infusion. However, l-arginine infusion induced a significant elevation of renal blood flow from 50 ± 3 to 94 ± 12 ml/min (means ± sem, P < 0.01). 3. Simultaneous infusion of NG-monomethyl-l-arginine (0.5 μmol min−1 kg−1) significantly inhibited the increase in renal blood flow produced by l-arginine (15 μmol min−1 kg−1) without significant changes in mean arterial blood pressure or heart rate. 4. Pretreatment with atropine completely inhibited the l-arginine-induced increase in renal blood flow, whereas pretreatment with indomethacin attenuated it (63 ± 4 versus 82 ± 10 ml/min, P < 0.05). 5. A continuous infusion of l-arginine increased renal blood flow in the intact kidney (55 ± 3 versus 85 ± 9 ml/min, P < 0.05), but not in the contralateral denervated kidney (58 ± 3 versus 56 ± 4 ml/min, P > 0.05). 6. These results suggest that intravenously administered l-arginine produces an elevation of renal blood flow, which may be mediated by facilitation of endogenous acetylcholine-induced release of endothelium-derived relaxing factor and vasodilatory prostaglandins.

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Patterned cardiovascular responses to sleep and nonrespiratory arousals in a porcine model

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.4.1285 ◽

1998 ◽

Vol 85 (4) ◽

pp. 1285-1291 ◽

Cited By ~ 7

Author(s):

Sandrine H. Launois ◽

Joseph H. Abraham ◽

J. Woodrow Weiss ◽

Debra A. Kirby

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Eye Movement ◽

Arterial Blood Pressure ◽

Vascular Resistance ◽

Mean Arterial Blood Pressure ◽

Rapid Eye Movement ◽

Rapid Eye Movement Sleep ◽

Arterial Blood

Patients with obstructive sleep apnea experience marked cardiovascular changes with apnea termination. Based on this observation, we hypothesized that sudden sleep disruption is accompanied by a specific, patterned hemodynamic response, similar to the cardiovascular defense reaction. To test this hypothesis, we recorded mean arterial blood pressure, heart rate, iliac blood flow and vascular resistance, and renal blood flow and vascular resistance in five pigs instrumented with chronic sleep electrodes. Cardiovascular parameters were recorded during quiet wakefulness, during non-rapid-eye-movement and rapid-eye-movement sleep, and during spontaneous and induced arousals. Iliac vasodilation (iliac vascular resistance decreased by −29.6 ± 4.1% of baseline) associated with renal vasoconstriction (renal vascular resistance increased by 10.3 ± 4.0%), tachycardia (heart rate increase: +23.8 ± 3.1%), and minimal changes in mean arterial blood pressure were the most common pattern of arousal response, but other hemodynamic patterns were observed. Similar findings were obtained in rapid-eye-movement sleep and for acoustic and tactile arousals. In conclusion, spontaneous and induced arousals from sleep may be associated with simultaneous visceral vasoconstriction and hindlimb vasodilation, but the response is variable.

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Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1991.261.4.h982 ◽

1991 ◽

Vol 261 (4) ◽

pp. H982-H988

Author(s):

J. H. Sindrup ◽

J. Kastrup ◽

H. Christensen ◽

B. Jorgensen

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Arterial Blood Pressure ◽

Flow Rate ◽

Mean Arterial Blood Pressure ◽

Blood Flow Rate ◽

Tissue Blood Flow ◽

Peripheral Blood Flow ◽

Arterial Blood

Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit were used for measurement of blood flow rates. An automatic portable blood pressure recorder and processor unit was used for measurement of systolic blood pressure, diastolic blood pressure, and heart rate every 15 min. The change from upright to supine position at the beginning of the night period was associated with a 30-40% increase in blood flow rate and a highly significant decrease in mean arterial blood pressure and heart rate (P less than 0.001 for all). Approximately 100 min after the subjects went to sleep an additional blood flow rate increment (mean 56%) and a simultaneous significant decrease in mean arterial blood pressure (P less than 0.001) were observed. The duration of this hyperemic phase was 116 min. A highly significant reduction of the subcutaneous vascular resistance (50%) was demonstrated during the hyperemic blood flow rate phase compared with the surrounding phases (P less than 0.0001). The synchronism of the nocturnal subcutaneous hyperemia and the decrease in systemic mean arterial blood pressure point to a common, possibly central nervous or humoral, eliciting mechanism.

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Cerebral blood flow and behavior during brain stimulation in the goat

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1977.232.5.h495 ◽

1977 ◽

Vol 232 (5) ◽

pp. H495-H499

Author(s):

M. Manrique ◽

E. Alborch ◽

J. M. Delgado

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Arterial Blood Pressure ◽

Maxillary Artery ◽

Internal Maxillary Artery ◽

Arterial Blood ◽

And Behavior ◽

Stimulation Of

Cerebral blood flow, heart rate, arterial blood pressure, and behavior were studied in conscious goats during electrical stimulation of the diencephalon and mesencephalon. Stimulation of the subthalamic area produced a considerable increase in ipsilateral cerebral blood flow and heart rate, accompanied by either a small or a large increase in systemic arterial blood pressure. Cardiovascular effects were associated with changes in alertness. The increase in cerebral blood flow was partially abolished by previous administration of atropine directly into the internal maxillary artery. Stimulation of the mesencephalic reticular formation caused a marked increase in blood pressure with no change or with some decrease in cerebral blood flow. After administration of phentolamine into the internal maxillary artery, stimulation produced increase in cerebral blood flow. The behavioral response consisted of restlessness and attempted flight. These results suggest the existence of cholinergic vasodilator and adrenergic vasoconstrictor pathways to cerebral blood vessels that may be stimulated electrically.

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Effect of intravenous infusion of adrenaline on the cardiovascular responses to distal body subatmospheric pressure in man

Clinical Science ◽

10.1042/cs0750389 ◽

1988 ◽

Vol 75 (4) ◽

pp. 389-394 ◽

Cited By ~ 7

Author(s):

I. W. Fellows ◽

I. A. MacDonald ◽

T. Bennett ◽

D. P. O'Donoghue

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Arterial Blood Pressure ◽

Forearm Blood Flow ◽

Cardiovascular Responses ◽

Saline Infusion ◽

Subatmospheric Pressure ◽

Arterial Blood ◽

Adrenaline Infusion

1. On two separate occasions, at least 1 week apart, seven young healthy male subjects received intravenous infusions of either adrenaline [0.27 nmol (50 ng) min−1 kg−1] or saline (154 mmol/l NaCl), plus ascorbic acid (5.68 mmol/l), over 30 min. 2. On each occasion, the subjects were exposed to distal body subatmospheric pressure (DBSP), 0 to 50 mmHg (0 to 6.65 kPa) in 10 mmHg (1.33 kPa) steps, before infusion, during the final 15 min of the infusion, and at 15 min and 30 min after the cessation of the infusion. 3. Venous adrenaline concentrations of 2.85 ±0.22 nmol/l were achieved during the adrenaline infusion, compared with 0.49 ± 0.07 nmol/l during the saline infusion (P < 0.001). At 15 min and at 30 min after cessation of the adrenaline infusion, venous adrenaline concentrations had fallen to levels similar to those achieved after the cessation of the saline infusion. 4. Heart rate rose significantly from 58 ±4 beats/min to 67 ±4 beats/min during the adrenaline infusion (P < 0.05), but there was no further significant change in response to 50 mmHg (6.65 kPa) DBSP. At 30 min after the cessation of the adrenaline infusion, heart rate rose from 60 ± 4 beats/min to 78 ± 7 beats/min in response to 50 mmHg DBSP. This increase was significantly greater than that observed before the adrenaline infusion [58 ± 4 beats/min to 69 ±7 beats/min during 50 mmHg (6.65 kPa) DBSP; P < 0.01]. 5. During the infusion of adrenaline, systolic arterial blood pressure rose and diastolic arterial blood pressure fell, but the blood pressure responses to DBSP were unaffected. 6. Forearm blood flow increased significantly during adrenaline infusion but there was no significant difference in the fall in forearm blood flow during DBSP compared with the values before infusion. At 15 min after the cessation of the adrenaline infusion, forearm vascular resistance rose proportionately more in response to DBSP than it had before the adrenaline infusion (P < 0.05). 7. These results are consistent with adrenaline-mediated facilitation of sympathetic neuronal release of noradrenaline in the heart and in the forearm vascular bed.

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Astrocytes monitor cerebral perfusion and control systemic circulation to maintain brain blood flow

Nature Communications ◽

10.1038/s41467-019-13956-y ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 17

Author(s):

Nephtali Marina ◽

Isabel N. Christie ◽

Alla Korsak ◽

Maxim Doronin ◽

Alexey Brazhe ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Arterial Blood Pressure ◽

Cerebral Perfusion ◽

Brain Perfusion ◽

Brain Blood Flow ◽

Sympathetic Control ◽

Arterial Blood ◽

Control Circuits

AbstractAstrocytes provide neurons with essential metabolic and structural support, modulate neuronal circuit activity and may also function as versatile surveyors of brain milieu, tuned to sense conditions of potential metabolic insufficiency. Here we show that astrocytes detect falling cerebral perfusion pressure and activate CNS autonomic sympathetic control circuits to increase systemic arterial blood pressure and heart rate with the purpose of maintaining brain blood flow and oxygen delivery. Studies conducted in experimental animals (laboratory rats) show that astrocytes respond to acute decreases in brain perfusion with elevations in intracellular [Ca2+]. Blockade of Ca2+-dependent signaling mechanisms in populations of astrocytes that reside alongside CNS sympathetic control circuits prevents compensatory increases in sympathetic nerve activity, heart rate and arterial blood pressure induced by reductions in cerebral perfusion. These data suggest that astrocytes function as intracranial baroreceptors and play an important role in homeostatic control of arterial blood pressure and brain blood flow.

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Is there diurnal variation of the vestibulosympathetic reflex: implications for orthostatic hypotension

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00930.2012 ◽

2013 ◽

Vol 305 (10) ◽

pp. H1555-H1559

Author(s):

Chester A. Ray ◽

Charity L. Sauder ◽

Stephanie A. Chin-Sang ◽

Jonathan S. Cook

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Diurnal Variation ◽

Orthostatic Hypotension ◽

Arterial Blood Pressure ◽

Muscle Sympathetic Nerve Activity ◽

Arterial Blood ◽

Calf Blood Flow ◽

Vestibulosympathetic Reflex

Incidences of adverse cardiac events and orthostatic hypotension are associated with diurnal variations. The primary purpose of the present study was to determine if the vestibulosympathetic reflex (VSR) follows a diurnal variation in humans. We hypothesized that the VSR would be attenuated at night based on the relation between melatonin and the VSR. Arterial blood pressure, heart rate, calf blood flow, and muscle sympathetic nerve activity (MSNA) were measured in nine healthy subjects (28 ± 1 yr, 5 men and 4 women) at rest and during head-down rotation. Each subject was tested during the day at 11:34 ± 13 and again at night 22:10 ± 5. MSNA was significantly decreased at night compared with day (8 ± 1 vs. 11 ± 2 bursts/min, respectively, P < 0.02). Heart rate and arterial blood pressure at rest were significantly increased at night compared with day (heart rate: 70 ± 4 vs. 66 ± 4 beats/min and mean arterial blood pressure: 91 ± 2 vs. 87 ± 1 mmHg, respectively). MSNA and hemodynamic responses to head-down rotation were not significantly altered at night compared with day (changes of 3 ± 1 bursts/min and 25 ± 6% for MSNA and calf blood flow, respectively). The data indicate that MSNA at rest decreases during the late evening hours and exhibits a diurnal variation, whereas the VSR does not. In summary, diurnal variation of orthostatic hypotension in humans does not appear to be associated with changes in the VSR and MSNA at rest.

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Regulation of arterial blood pressure in the common green iguana

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1975.228.2.386 ◽

1975 ◽

Vol 228 (2) ◽

pp. 386-391 ◽

Cited By ~ 17

Author(s):

LA Hohnke

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Arterial Pressure ◽

Arterial Blood Pressure ◽

Venous Pressure ◽

Arterial Blood Flow ◽

Arterial Blood ◽

Head Up Tilt ◽

Carotid Arterial

Arterial blood pressure (ABP) responses to graded hemorrhage and passive head-up tilt were studied in restrained, anesthetized, and unanesthetized iguanas. The ABP fell slowly in response to hemorrhage up to a critical deficit of 35 plus or minus 19% of the estimated blood volume; the rate of ABP fall then increased nearly 40-fold to continued hemorrhage. Increased heart rate and decreased femoral arterial blood flow accompanied progressive hemorrhage. Propranolol (2-3 mug/kg) did not appreciably alter arterial pressure-hemorrhage curves but hemorrhage-induced increases in heart rate were diminished nearly 50%. Atropine had little effect on either the blood pressure or heart rate changes induced by hemorrhage. During passive tilts of 0-90 degrees carotid arterial pressure fell 33% before returning to control levels (2 min). Heart rate increased and femoral arterial blood flow and central venous pressure fell in response to head-up tilts. It is concluded that hemorrhage and passive head-up tilting can induce reflex cardiovascular changes that assist ABP regulation in iguanas.

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Neurovascular responses to mental stress in the supine and upright postures

Journal of Applied Physiology ◽

10.1152/japplphysiol.01285.2007 ◽

2008 ◽

Vol 104 (4) ◽

pp. 1129-1136 ◽

Cited By ~ 43

Author(s):

Nathan T. Kuipers ◽

Charity L. Sauder ◽

Jason R. Carter ◽

Chester A. Ray

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Arterial Blood Pressure ◽

Doppler Ultrasound ◽

Mean Arterial Blood Pressure ◽

Mental Stress ◽

Upright Posture ◽

Vascular Responses ◽

Arterial Blood

The purpose of this study was to determine neurovascular responses to mental stress (MS) in the supine and upright postures. MS was elicited in 23 subjects (26 ± 1 yr) by 5 min of mental arithmetic. In study 1 ( n = 9), Doppler ultrasound was used to measure mean blood flow velocity in the renal (RBFV) and superior mesenteric arteries (SMBFV), and venous occlusion plethysmography was used to measure forearm blood flow (FBF). In study 2 ( n = 14), leg blood flow (LBF; n = 9) was measured by Doppler ultrasound, and muscle sympathetic nerve activity (MSNA; n = 5) was measured by microneurography. At rest, upright posture increased heart rate and MSNA and decreased LBF, FBF, RBFV, and SMBFV and their respective conductances. MS elicited similar increases in mean arterial blood pressure (∼12 mmHg) and heart rate (∼17 beats/min), regardless of posture. MS in both postures elicited a decrease in RBFV, SMBFV, and their conductances and an increase in LBF, FBF, and their conductances. Changes in blood flow were blunted in the upright posture in all vascular beds examined, but the pattern of the vascular response was the same as the supine posture. MS did not change MSNA in either posture (change: ∼1 ± 3 and ∼3 ± 3 bursts/min, respectively). In conclusion, the augmented sympathetic activity of the upright posture does not alter heart rate, mean arterial blood pressure, or MSNA responses to MS. MS elicits divergent vascular responses in the visceral and peripheral vasculature. These results indicate that, although the upright posture attenuates vascular responses to MS, the pattern of neurovascular responses does not differ between postures.

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