Cardiovascular and Sympatho-Adrenal Responses to Mental Stress in Primary Hypertension

1993 ◽  
Vol 85 (4) ◽  
pp. 401-409 ◽  
Author(s):  
Madeleine Lindqvist ◽  
Thomas Kahan ◽  
Anders Melcher ◽  
Paul Hjemdahl
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Neuropeptide Y ◽  
Mental Stress ◽  
Forearm Blood Flow ◽  
Primary Hypertension ◽  
Hypertensive Patients ◽  
Control Subjects ◽  
Venous Plasma

1. Eleven untreated men with mild to moderate primary hypertension and 10 normotensive control subjects were studied at rest and during a mental stress test (Stroop colour word conflict test), which has previously been used in studies of hypertensive patients with regard to non-invasive cardiovascular variables and venous plasma catecholamine concentrations. 2. Heart rate, central cardiovascular pressures, cardiac output (thermodilution) and forearm blood flow (strain gauge plethysmography) were determined. Systemic and forearm vascular resistances were calculated. Arterial and venous plasma adrenaline and noradrenaline concentrations were measured by h.p.l.c., and arterial noradrenaline spillover and noradrenaline overflow from the forearm were assessed by isotope methodology ([3H]noradrenaline). Neuropeptide Y-like immunoreactivity was measured by radioimmunoassay. 3. In hypertensive patients heart rate, arterial blood pressure, cardiac output and forearm blood flow increased by 28%, 13%, 37% and 115%, respectively, and forearm and systemic vascular resistances decreased by 48% and 21%, respectively (P <0.001 for all responses), during stress. These responses were not different from those of the control group. 4. Arterial noradrenaline spillover rose by 63% and noradrenaline overflow from the forearm rose by 150% in the hypertensive patients in response to mental stress (P <0.001); no significant group differences could be demonstrated. However, the forearm noradrenaline overflow response to stress tended to be greater in the hypertensive group (P = 0.11). Arterial adrenaline concentrations doubled in both groups (P <0.001). 5. Arterial neuropeptide Y-like immunoreactivity increased slightly and similarly in the two groups (+7% in hypertensive patients and +9% in control subjects, P <0.05 for both) in response to mental stress. No net overflow of neuropeptide-Y-like immunoreactivity could be detected over the forearm. 6. It is concluded that the cardiovascular and sympatho-adrenal responses to mental stress evaluated in this study are similar in hypertensive patients and control subjects. Stress-induced vasodilatation occurs in the forearm despite signs of increased local sympathetic activity, indicating that powerful neurohormonal vasodilator mechanisms are activated by mental stress.

Haemodynamic effects of physiological concentrations of circulating noradrenaline in man

1988 ◽  
Vol 75 (5) ◽  
pp. 469-475 ◽  
Author(s):  
Peter C. Chang ◽  
Eugene Kriek ◽  
Jacques A. Van Der Krogt ◽  
Gerard-Jan Blauw ◽  
Peter Van Brummelen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Vascular Resistance ◽  
Forearm Blood Flow ◽  
Haemodynamic Effects ◽  
Plasma Noradrenaline ◽  
Arterial Blood ◽  
Forearm Vascular Resistance ◽  
Venous Plasma

1. To define the role of circulating noradrenaline in cardiovascular regulation, threshold concentrations for haemodynamic effects were determined in arterial and venous plasma of eight healthy volunteers. 2. Five doses of noradrenaline, 0–54 ng min−1 kg−1, were infused intravenously in random order and single-blind for 15 min per dose. Changes in intra-arterial blood pressure, heart rate, forearm blood flow and forearm vascular resistance were determined, and plasma noradrenaline was measured in arterial and venous blood samples. 3. Significant increases in systolic and diastolic blood pressure were found at arterial and venous plasma noradrenaline concentrations (means ±sem) of 3.00 ± 0.23 and 1.35 ±0.12 nmol/l, respectively. A significant decrease in heart rate was found at arterial and venous plasma noradrenaline concentrations of 8.99 ± 0.69 and 3.09 ± 0.60 nmol/l, respectively. The lower doses of noradrenaline tended to increase forearm blood flow and to decrease forearm vascular resistance, whereas the higher doses had no consistent effect on forearm haemodynamics. 4. During the noradrenaline infusions 73 ± 5% of the increase in arterial plasma noradrenaline concentration was extracted in the forearm. 5. The venous plasma noradrenaline threshold concentration was found to be much lower than previously reported. It is concluded that arterial and venous plasma noradrenaline concentrations which are readily encountered in physiological circumstances elicit haemodynamic effects.

Forearm vasoconstriction to endothelin-1 is impaired, but constriction to sarafotoxin 6c and vasodilatation to BQ-123 unaltered, in patients with essential hypertension

2002 ◽  
Vol 103 (s2002) ◽  
pp. 53S-58S ◽  
Author(s):  
Charles J. FERRO ◽  
William G. HAYNES ◽  
Malcolm F. HAND ◽  
David J. WEBB
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Essential Hypertension ◽  
Receptor Agonist ◽  
Forearm Blood Flow ◽  
Hypertensive Patients ◽  
Control Subjects ◽  
Eta Receptor ◽  
Etb Receptor ◽  
And Control

The importance of endothelin-1 (ET-1) in the pathophysiology of essential hypertension is unclear. We therefore compared the effects of endothelin ETA receptor blockade and the stimulation of ETA and ETB receptors, and their interaction with the sympathetic nervous system, in the forearm resistance vessels of patients with essential hypertension and healthy control subjects. A total of 27 untreated patients with essential hypertension (blood pressure >160/100mmHg) and 25 normotensive (blood pressure <140/90mmHg) age- and sex-matched control subjects participated in these studies. A total of 10 patients and 10 controls took part in each phase. Locally active doses of study drugs were infused into the non-dominant brachial artery, while forearm blood flow was measured by venous occlusion plethysmography. A 60min infusion of BQ-123 (an ETA receptor antagonist; 100nmol/min) significantly increased forearm blood flow by 40±8% in hypertensive patients and by 35±5% in controls, with no difference between groups (P = 0.49). Forearm vasoconstriction to ET-1 (an ETA and ETB receptor agonist; 5 pmol/min) for 90min was significantly blunted in hypertensive patients (21±4%) compared with control subjects (37±3%; P = 0.0001). Forearm vasoconstriction to sarafotoxin S6c (an ETB receptor agonist; 10 pmol/min) for 90min was similar in hypertensive patients (44±5%) and control subjects (48±4%; P = 0.95). Sympathetically mediated vasoconstriction produced by lower-body negative pressure was not different in hypertensive patients compared with controls, and was not affected by infusion of ET-1 or sarafotoxin S6c. There were no differences in the observed increase in forearm blood flow with a control vasodilator (sodium nitroprusside) or the observed decrease in forearm blood flow with a control vasoconstrictor (noradrenaline) between hypertensive patients and control subjects. BQ-123 produced a significant increase in forearm blood flow in hypertensive patients, consistent with the anti-hypertensive actions of this agent. In conclusion, forearm vasoconstriction to ET-1, but not to sarafotoxin S6c, was reduced in patients with essential hypertension, consistent with possible down-regulation of the ETA receptor in this condition.

Diastolic pressure and peripheral resistance during stellate ganglion stimulation

1963 ◽  
Vol 204 (1) ◽  
pp. 71-72 ◽  
Author(s):  
Edward D. Freis ◽  
Jay N. Cohn ◽  
Thomas E. Liptak ◽  
Aristide G. B. Kovach
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Total Peripheral Resistance ◽  
Diastolic Pressure ◽  
Stellate Ganglion ◽  
Peripheral Resistance ◽  
Resistance Vessels ◽  
Left Stellate Ganglion ◽  
Increased Blood Flow

The mechanism of the diastolic pressure elevation occurring during left stellate ganglion stimulation was investigated. The cardiac output rose considerably, the heart rate remained essentially unchanged, and the total peripheral resistance fell moderately. The diastolic rise appeared to be due to increased blood flow rather than to any active changes in resistance vessels.

scholarly journals Development of a Simple ImageJ-Based Method for Dynamic Blood Flow Tracking in Zebrafish Embryos and Its Application in Drug Toxicity Evaluation

Inventions ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 65 ◽  
Author(s):  
Fiorency Santoso ◽  
Bonifasius Putera Sampurna ◽  
Yu-Heng Lai ◽  
Sung-Tzu Liang ◽  
Erwei Hao ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Blood Cell ◽  
Stroke Volume ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Video Recording ◽  
Cardiovascular Function ◽  
Zebrafish Embryos

This study aimed to develop a simple and cost-effective method to measure blood flow in zebrafish by using an image-based approach. Three days post fertilization (dpf) zebrafish embryos were mounted with methylcellulose and subjected to video recording for tracking blood flow under an inverted microscope equipped with a high-speed CCD camera. In addition, Hoffman lens was used to enhance the blood cell contrast. The red blood cell movement was tracked by using the TrackMate plug-in in the ImageJ image processing program. Moreover, Stack Difference and Time Series Analyzer plug-in were used to detect dynamic pixel changes over time to calculate the blood flow rate. In addition to blood flow velocity and heart rate, the effect of drug treatments on other cardiovascular function parameters, such as stroke volume and cardiac output remains to be explored. Therefore, by using this method, the potential side effects on the cardiovascular performance of ethyl 3-aminobenzoate methanesulfonate (MS222) and 3-isobutyl-1-methylxanthine (IBMX) were evaluated. MS222 is a common anesthetic, while IBMX is a naturally occurring methylxanthine. Compared to normal embryos, MS222- and IBMX-treated embryos had a reduced blood flow velocity by approximately 72% and 58%, respectively. This study showed that MS222 significantly decreased the heart rate, whereas IBMX increased the heart rate. Moreover, it also demonstrated that MS222 treatment reduced 50% of the stroke volume and cardiac output. While IBMX decreased the stroke volume only. The results are in line with previous studies that used expensive instruments and complicated software analysis to assess cardiovascular function. In conclusion, a simple and low-cost method can be used to study blood flow in zebrafish embryos for compound screening. Furthermore, it could provide a precise measurement of clinically relevant cardiac functions, specifically heart rate, stroke volume, and cardiac output.

Hemodynamic effects of posterior hypothalamic injection of neuropeptide Y in awake rats

1991 ◽  
Vol 261 (3) ◽  
pp. H814-H824 ◽  
Author(s):  
J. R. Martin ◽  
M. M. Knuepfer ◽  
T. C. Westfall
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Neuropeptide Y ◽  
Cardiovascular System ◽  
Peripheral Resistance ◽  
Hypothalamic Nucleus ◽  
Initial Increase ◽  
System Control ◽  
Posterior Hypothalamic Nucleus ◽  
Freely Moving

Unilateral microinjection of neuropeptide Y (NPY) into the posterior hypothalamic nucleus was previously found to evoke a sympathoexcitatory-mediated increase in mean arterial pressure (MAP) in urethan-anesthetized rats. In this study, the effect of unilateral injection of NPY into the posterior hypothalamic nucleus on the cardiovascular system of conscious, freely moving rats was determined. Microinjection of NPY (0.2-2.4 nmol) or the cholinergic agonist carbachol (0.5-5.5 nmol) resulted in concentration-dependent increases in MAP. Pretreatment of animals with 7.5 mg/kg iv of the ganglionic blocker pentolinium resulted in a blockade of the increase in MAP evoked by microinjection of NPY (2.4 nmol) or carbachol (3.3 nmol). Despite their similarity of effects on MAP, NPY and carbachol evoked different changes in heart rate. NPY increased heart rate, whereas carbachol evoked a biphasic change in heart rate that consisted of an initial increase followed by a decrease. In addition, carbachol caused increases in both hindquarter and mesenteric vascular resistances, whereas NPY caused a short-lasting increase in mesenteric resistance and a tendency toward an increase in hindquarter resistance. Both NPY and carbachol increased total peripheral resistance while NPY decreased stroke volume. Cardiac output was not significantly affected by either NPY or carbachol, although NPY had a tendency to decrease cardiac output. These results suggest that microinjection of NPY or carbachol into the posterior hypothalamic nucleus of conscious rats evokes an increase in MAP primarily as a result of sympathoexcitation and that NPY and carbachol selectively affect autonomic nervous system control of the cardiovascular system.

Autonomic Function in Patients on Continuous Ambulatory Peritoneal Dialysis

1998 ◽  
Vol 18 (1) ◽  
pp. 46-51 ◽  
Author(s):  
Sarbjit V. Jassal ◽  
Judith A. Allen ◽  
James F. Douglas ◽  
Robert w. Stout
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Peritoneal Dialysis ◽  
Body Surface ◽  
Autonomic Function ◽  
Matched Control ◽  
Care Hospital ◽  
Surface Cooling ◽  
Deep Breath ◽  
Control Subjects

Objective To investigate sympathetic function in the peripheries of patients on chronic ambulatory peritoneal dialysis (CAPD) using noninvasive techniques. Design Comparison of peripheral blood flowresponses in sympathetic vasoconstrictor reflexes in CAPD patients and matched control subjects. Setting Tertiary care hospital and research institution. Patients Twenty-three clinically stable CAPD patients and 23 control subjects matched for age, sex, and drug therapy. Main Outcome Measures Sympathetic activity assessed from the reductions in hand and foot blood flow induced by a deep breath and by body surface cooling. Cardiac autonomic activity measured by the changes in heart rate produced by deep breathing, a Valsalva maneuver, and standing from lying. Results A deep breath induced mean decreases in hand blood flow of 65.1% in the patients and 82.8% in their matched controls. Corresponding reductions in the foot were 46.0% and 70.0%. Body surface cooling reduced mean hand blood flow by 50.3% in the patients an d 71.8% in the control subjects. Corresponding values in the foot were 26.7% and 43.6%. The differences in response between the patients and their matched control subjects were all significant (p < 0.01). Cardiac autonomic function assessed by standard tests of heart rate variability was significantly impaired in the patients compared with the control subjects in two of the three tests used (p < 0.001). Conclusions Cardiovascular autonomic impairment can affect the peripheral circulation as well as the heart in patients on dialysis, and this may have implications for cardiovascular homeostasis.

Effects of caffeine on blood pressure, heart rate, and forearm blood flow during dynamic leg exercise

1998 ◽  
Vol 85 (1) ◽  
pp. 154-159 ◽  
Author(s):  
Jason W. Daniels ◽  
Paul A. Molé ◽  
James D. Shaffrath ◽  
Charles L. Stebbins
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Systolic Blood Pressure ◽  
Skin Temperature ◽  
Rectal Temperature ◽  
Forearm Blood Flow ◽  
Dynamic Exercise ◽  
Ang Ii ◽  
Leg Exercise

This study examined the acute effects of caffeine on the cardiovascular system during dynamic leg exercise. Ten trained, caffeine-naive cyclists (7 women and 3 men) were studied at rest and during bicycle ergometry before and after the ingestion of 6 mg/kg caffeine or 6 mg/kg fructose (placebo) with 250 ml of water. After consumption of caffeine or placebo, subjects either rested for 100 min (rest protocol) or rested for 45 min followed by 55 min of cycle ergometry at 65% of maximal oxygen consumption (exercise protocol). Measurement of mean arterial pressure (MAP), forearm blood flow (FBF), heart rate, skin temperature, and rectal temperature and calculation of forearm vascular conductance (FVC) were made at baseline and at 20-min intervals. Plasma ANG II was measured at baseline and at 60 min postingestion in the two exercise protocols. Before exercise, caffeine increased both systolic blood pressure (17%) and MAP (11%) without affecting FBF or FVC. During dynamic exercise, caffeine attenuated the increase in FBF (53%) and FVC (50%) and accentuated exercise-induced increases in ANG II (44%). Systolic blood pressure and MAP were also higher during exercise plus caffeine; however, these increases were secondary to the effects of caffeine on resting blood pressure. No significant differences were observed in heart rate, skin temperature, or rectal temperature. These findings indicate that caffeine can alter the cardiovascular response to dynamic exercise in a manner that may modify regional blood flow and conductance.

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