Muscle–Nerve Sympathetic Activity in Man. Relationship to Blood Pressure in Resting Normo- and Hyper-Tensive Subjects

1978 ◽  
Vol 55 (s4) ◽  
pp. 387s-389s ◽  
Author(s):  
G. Sundlöf ◽  
B. G. Wallin
Keyword(s):  
Blood Pressure ◽  
Negative Correlation ◽  
Sympathetic Activity ◽  
Diastolic Pressure ◽  
Pressure Fluctuations ◽  
Blood Pressure Level ◽  
Heart Beat ◽  
Arterial Blood ◽  
Muscle Nerve ◽  
Pressure Changes

1. Simultaneous recordings of multi-unit muscle nerve sympathetic activity and arterial blood pressure were made in 29 subjects, 17 healthy and 12 hypertensive. The neural activity, quantified by counting the number of pulse-synchronous sympathetic bursts in the mean voltage neurogram (burst incidence), was plotted against blood pressure. The effect of spontaneous temporary blood pressure fluctuations was studied by correlating different pressure parameters of individual heart beats to the occurrence of a sympathetic burst. 2. Between subjects there were marked differences in burst incidence but no correlation was found to interindividual differences in blood pressure level. 3. When for each heart beat the occurrence of a burst was correlated to different pressure parameters there was a close negative correlation to diastolic, a low correlation to systolic, and an intermediate negative correlation to mean blood pressure. 4. In a given subject, when comparing heart beats with the same diastolic pressure, the occurrence and the amplitudes of the sympathetic bursts were higher during falling than during rising pressure. This directional dependence of the muscle—nerve sympathetic activity was slightly more pronounced in the hypertensive group, but this was considered secondary to the hypertension. 5. The findings of an intimate correlation with dynamic variations in blood pressure and the absence of correlation to the static blood pressure suggest that the sympathetic outflow to skeletal muscle is of importance for buffering acute blood pressure changes but has little influence on the long-term blood pressure.

Arterial Blood Pressure - The Pattern of Change in Twin Pregnancies

1985 ◽  
Vol 34 (3-4) ◽  
pp. 217-223 ◽  
Author(s):  
D.M. Campbell ◽  
A.J. Campbell
Keyword(s):  
Blood Pressure ◽  
Body Size ◽  
Weight Gain ◽  
Diastolic Blood Pressure ◽  
Arterial Blood Pressure ◽  
Diastolic Pressure ◽  
Arterial Blood ◽  
Pressure Changes ◽  
Twin Pregnancies ◽  
Weight Gain During Pregnancy

AbstractAn epidemiological study of all primigravid twin pregnancies delivered in Aberdeen between 1950 and 1969 was performed to determine the pattern of arterial blood pressure changes. There is a greater fall from non-pregnant levels in diastolic blood pressure by mid pregnancy and a greater rise of diastolic pressure by delivery. These changes are independent of age, body size and rate of weight gain during pregnancy. The expected increased incidence of proteinuric pre-eclampsia is also independent of rate of weight gain when defined for twin pregnancies.

Increase in Muscle Nerve Sympathetic Activity in Humans after Food Intake

1994 ◽  
Vol 86 (2) ◽  
pp. 159-167 ◽  
Author(s):  
JAN Fagius ◽  
Christian Berne
Keyword(s):  
Blood Pressure ◽  
Food Intake ◽  
Sympathetic Activity ◽  
Insulin Response ◽  
Mixed Meal ◽  
Muscle Nerve ◽  
Intermediate Response ◽  
Normotensive Subjects ◽  
Pressure Changes ◽  
Effect Of Glucose

1. The influence of the intake of different nutrients on muscle nerve sympathetic activity was studied by use of microneurography. Muscle nerve sympathetic activity, heart rate, blood pressure and the insulin response were monitored for 90 min in 39 healthy, lean, normotensive subjects (mean age 26 years) who received 100 g of glucose in 300 ml of water (n = 8), 50 g of fat in 250 ml of water (n = 8), 100 g of lean meat corresponding to 40 g of protein with 250 ml of water (n = 8), 300 ml of water only (n = 7) or a mixed meal (1750 kJ) (n = 8). 2. All types of food evoked an increase in muscle nerve sympathetic activity whereas water caused no change. The increase in muscle nerve sympathetic activity was already significant at 15–30 min and was still strongly significant at 90 min. The effect of glucose was significantly greater than that of fat and protein; the mixed meal caused an intermediate response. Blood pressure changes were minor. 3. It is concluded that a sustained increase in muscle nerve sympathetic activity occurs regularly after any type of food intake. A rise in muscle nerve sympathetic activity takes place in the absence of an insulin response, and insulin contributes to only part of the increase after ingestion of glucose or a mixed meal. The muscle nerve sympathetic activity response is thought to be of importance for the redistribution of blood to the splanchnic region after a meal. Lack of this response is likely to explain postprandial hypotension in autonomic failure.

scholarly journals Blood pressure level and laboratory indicators of disease severity in patients with arterial hypertension and COVID-19

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
K Popov ◽  
A Novitskiy ◽  
Y Shvarts
Keyword(s):  
Blood Pressure ◽  
Multivariate Analysis ◽  
Arterial Hypertension ◽  
Negative Correlation ◽  
Diastolic Pressure ◽  
Negative Relationship ◽  
Laboratory Parameters ◽  
Acute Period ◽  
Nonparametric Correlation ◽  
The Relationship

Abstract Funding Acknowledgements Type of funding sources: None. Background. Many patients with COVID-19 suffer from arterial hypertension and have marked variations in blood pressure (BP) during the acute period of infection. The reasons for such changes are poorly understood. Purpose. To assess the relationship between the level of BP and the severity of changes in the main clinical and laboratory parameters in patients with arterial hypertension and with a moderate course of COVID-19 at the stage of the height of the disease. Materials and methods. The study included 86 hospitalized patients with verified coronavirus disease of moderate severity: 46 of them were male, the median age was 65 years. Patients received adequate hypertension therapy for a long time. After hospitalization, treatment was adjusted if necessary. The level of laboratory parameters in the acute period of the disease was determined, including the electrolytes, C-reactive protein (CRP), albumin, ferritin, general blood test, etc. BP measured daily. The relationship between laboratory parameters and BP level was evaluated by nonparametric correlation using the Spearman coefficient and multivariate analysis based on the "generalized nonlinear model". Results. In 67.44% of patients with hypertension, an elevated BP level (>140/90) was observed against the background of moderate COVID-19. There was a significant negative correlation between the levels of CRP and BP throughout the stay in the hospital, the most significant is the 5th day of hospitalization. At the same time, a slightly stronger relationship is observed with diastolic BP (r = -0.4425) than with systolic BP (r = -0.3525). A similar trend is observed in all BP measurements. Besides, a negative correlation was found between potassium levels and BP values. The strongest association of potassium levels is with systolic BP on the day of hospitalization (r = -0.4850) and diastolic pressure on the 1st day of hospitalization (r = -0.3561). Multivariate analysis confirmed independent and reliable "influence" of CRP (p = 0.00018) and potassium (p = 0.03921) as independent predictors of diastolic pressure. Conclusions. Most patients with hypertension and moderate COVID-19 have elevated BP levels. There is a statistically significant negative relationship between the values of BP and levels of CRP and potassium. The obtained data may correspond to the existing hypothesis about the significant role of the kinin–kallikrein system in the pathogenesis of COVID-19.

scholarly journals Possible mechanism of the cardio-renal protective effects of AVE-0991, a non-peptide Mas-receptor agonist, in diabetic rats

2012 ◽  
Vol 13 (3) ◽  
pp. 334-340 ◽  
Author(s):  
Kulwinder Singh ◽  
Kuldeepak Sharma ◽  
Manjeet Singh ◽  
PL Sharma
Keyword(s):  
Blood Pressure ◽  
Receptor Agonist ◽  
Diastolic Pressure ◽  
Left Ventricular Pressure ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Protective Effects ◽  
Mas Receptor ◽  
Arterial Blood

Hypothesis: This study was designed to investigate the cardio-renal protective effect of AVE-0991, a non-peptide Mas-receptor agonist, and A-779, a Mas-receptor antagonist, in diabetic rats. Materials and methods: Wistar rats treated with streptozotocin (50 mg/kg, i.p., once), developed diabetes mellitus after 1 week. After 8 weeks, myocardial functions were assessed by measuring left ventricular developed pressure (LVDP), rate of left ventricular pressure development (d p/d tmax), rate of left ventricular pressure decay (d p/d tmin) and left ventricular end diastolic pressure (LVEDP) on an isolated Langendorff’s heart preparation. Further, mean arterial blood pressure (MABP) was measured by using the tail-cuff method. Assessment of renal functions and lipid profile was carried out using a spectrophotometer. Results: The administration of streptozotocin to rats produced persistent hyperglycaemia, dyslipidaemia and hypertension which consequently produced cardiac and renal dysfunction in 8 weeks. AVE0991 treatment produced cardio-renal protective effects, as evidenced by a significant increase in LVDP, d p/d tmax, d p/d tmin and a significant decrease in LVEDP, BUN, and protein urea. Further, AVE-0991 treatment for the first time has been shown to reduce dyslipidaemia and produced antihyperglycaemic activity in streptozotocin-treated rats. However, MABP and creatinine clearance remained unaffected with AVE-0991 treatment. Conclusions: AVE-0991 produced cardio-renal protection possibly by improving glucose and lipid metabolism in diabetic rats, independent of its blood pressure lowering action.

scholarly journals Pharmacological assessment of the contribution of the arterial baroreflex to sympathetic discharge patterns in healthy humans

2018 ◽  
Vol 119 (6) ◽  
pp. 2166-2175 ◽  
Author(s):  
Jacqueline K. Limberg ◽  
Elizabeth P. Ott ◽  
Walter W. Holbein ◽  
Sarah E. Baker ◽  
Timothy B. Curry ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Sympathetic Activity ◽  
High Threshold ◽  
Neural Activation ◽  
Afferent Activity ◽  
Cluster Number ◽  
Arterial Blood ◽  
Rate Coding ◽  
Low Threshold

To study how changes in baroreceptor afferent activity affect patterns of sympathetic neural activation, we manipulated arterial blood pressure with intravenous nitroprusside (NTP) and phenylephrine (PE) and measured action potential (AP) patterns with wavelet-based methodology. We hypothesized that 1) baroreflex unloading (NTP) would increase firing of low-threshold axons and recruitment of latent axons and 2) baroreflex loading (PE) would decrease firing of low-threshold axons. Heart rate (HR, ECG), arterial blood pressure (BP, brachial catheter), and muscle sympathetic nerve activity (MSNA, microneurography of peroneal nerve) were measured at baseline and during steady-state systemic, intravenous NTP (0.5–1.2 µg·kg−1·min−1, n = 13) or PE (0.2–1.0 µg·kg−1·min−1, n = 9) infusion. BP decreased and HR and integrated MSNA increased with NTP ( P < 0.01). AP incidence (326 ± 66 to 579 ± 129 APs/100 heartbeats) and AP content per integrated burst (8 ± 1 to 11 ± 2 APs/burst) increased with NTP ( P < 0.05). The firing probability of low-threshold axons increased with NTP, and recruitment of high-threshold axons was observed (22 ± 3 to 24 ± 3 max cluster number, 9 ± 1 to 11 ± 1 clusters/burst; P < 0.05). BP increased and HR and integrated MSNA decreased with PE ( P < 0.05). PE decreased AP incidence (406 ± 128 to 166 ± 42 APs/100 heartbeats) and resulted in fewer unique clusters (15 ± 2 to 9 ± 1 max cluster number, P < 0.05); components of an integrated burst (APs or clusters per burst) were not altered ( P > 0.05). These data support a hierarchical pattern of sympathetic neural activation during manipulation of baroreceptor afferent activity, with rate coding of active neurons playing the predominant role and recruitment/derecruitment of higher-threshold units occurring with steady-state hypotensive stress. NEW & NOTEWORTHY To study how changes in baroreceptor afferent activity affect patterns of sympathetic neural activation, we manipulated arterial blood pressure with intravenous nitroprusside and phenylephrine and measured sympathetic outflow with wavelet-based methodology. Baroreflex unloading increased sympathetic activity by increasing firing probability of low-threshold axons (rate coding) and recruiting new populations of high-threshold axons. Baroreflex loading decreased sympathetic activity by decreasing the firing probability of larger axons (derecruitment); however, the components of an integrated burst were unaffected.

Respiratory Origin of Fluctuations in Arterial Blood Pressure in Premature Infants With Respiratory Distress Syndrome

PEDIATRICS ◽  
1988 ◽  
Vol 81 (3) ◽  
pp. 399-403
Author(s):  
Jeffrey Perlman ◽  
Bradley Thach
Keyword(s):  
Premature Infants ◽  
Muscle Activity ◽  
Intraventricular Hemorrhage ◽  
Respiratory Muscle ◽  
Pressure Fluctuations ◽  
Esophageal Pressure ◽  
Arterial Blood ◽  
Gastric Pressure ◽  
Pressure Changes ◽  
Respiratory Muscle Activity

A variable fluctuating pattern of arterial BP often precedes intraventricular hemorrhage in mechanically ventilated preterm infants. To learn more about the origin of this pattern, arterial BP and respiratory muscle activity were studied in five intubated premature infants who were at high risk for intraventricular hemorrhage. We monitored esophageal pressure, gastric pressure, and arterial BP. Consistent findings were: (1) arterial BP fluctuations have the same frequency and direction of change as esophageal and gastric pressure changes associated with spontaneous breathing (R ranged from .93 to .98, P &lt; .001); (2) spontaneous apneic pauses were accompanied by sudden and complete cessation of arterial BP fluctuations; (3) large "cough-like" fluctuations in esophageal and gastric pressures, seen in all infants, were associated with the largest fluctuations in arterial BP; (4) cutaneous stimulation had negligible effect on fluctuation in arterial BP provided no change in esophageal and gastric pressures occurred; (5) the effects of change in esophageal and gastric pressures on arterial BP were nearly simultaneous (0.05 to 0.25 second latency); (6) respirator pressure fluctuations had negligible effects on the fluctuations in arterial BP. These data suggest that the fluctuations in arterial BP are directly related to respiratory muscle activity and are most consistent with the familiar pulsus paradoxus that occurs in various other cardiorespiratory diseases.

Abstract 2470: Augmented Tonic Activation Of Chemoreceptors May Contribute To Sympathetic Overactivity In Patients With Essential Hypertension

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Maciej Sinski ◽  
Jacek Lewandowski ◽  
Joanna Bidiuk ◽  
Piotr Abramczyk ◽  
Anna Dobosiewicz ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Essential Hypertension ◽  
Sympathetic Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Arterial Blood ◽  
Hemoglobin Saturation ◽  
Ambient Oxygen ◽  
Young Subjects ◽  
End Tidal ◽  
Carotid Body Chemoreceptors

Rationale : Peripheral chemoreflex contributes to regulation of arterial blood pressure and chemoreceptors respond not only to hypoxia but they are also continuously activated by normal ambient oxygen concentration. Stimulation of chemoreceptors activates sympathetic traffic and this response may be altered in subjects with essential hypertension.. Objective: The aim of our study was to investigate the effect of deactivation of carotid body chemoreceptors on sympathetic activity directly measured as MSNA (muscle sympathetic nerve activity) in young subjects with mild to moderate untreated hypertension. Methods: Twelve patients with essential hypertension (36±9 years, all men, BMI 29±4 kg/m 2 ,) and 8 controls (37±7, men BMI 27±5kg/m 2 ) participated in the study. None of the patients or controls received any medications. MSNA (burst/minute and mean burst amplitude - au), systolic blood pressure (SBP) and diastolic blood pressure (DBP), heart rate (HR), ECG, hemoglobin saturation with oxygen (Sat%), end tidal CO 2 and respiratory movements were monitored and measured after 10 minute of respiration by non-rebreathing mask with 100% 0 2 or 21% O 2 applied in blinded fashion. Results: Hypertensives had higher resting MSNA (38.6 ±8.6 burst/min vs. 30.3±.7 burst/min, p<0.05), SBP (149.1± 9.9 vs. 124.1 ±11.6, p < 0.05) and DBP (92.1 ±8.6 vs. 78.1 ± 8.9, p< 0.05) than controls. Breathing with 100% oxygen caused significant decrease in MSNA in hypertensives (from 38.6 ± 8.6 burst/min to 26.3 burst/min ± 6.8 and from 100 ± 0 au to 86 ± 18 au, p< 0.05) and no change in MSNA in controls (30.3 ± 5.7 burst/min initially and 27.3 burst/min ± 6.2 after 100% 0 2 , 100 ± 0 au vs. 98 ± 11 au). Blood pressure, end tidal CO 2 , respiration frequency did not change significantly after hyperoxia while HR decreased (from 69.6 ± 9 to 64.1 ± 7 in hypertensives p<0.05 and from 67± 8 to 62.5 ± 7 in controls, p< 0.05). Sat% increased significantly in both groups to 99%. Conclusions: Increased sympathetic activity in young, untreated hypertensives may be caused by the elevated tonic chemoreflex activation.

Arterial pressure and muscle sympathetic nerve activity are increased after two hours of sustained but not cyclic hypoxia in healthy humans

2005 ◽  
Vol 98 (1) ◽  
pp. 343-349 ◽  
Author(s):  
Renaud Tamisier ◽  
Amit Anand ◽  
Luz M. Nieto ◽  
David Cunnington ◽  
J. Woodrow Weiss
Keyword(s):  
Blood Pressure ◽  
Arterial Pressure ◽  
Sympathetic Nerve ◽  
Sympathetic Activity ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Arterial Oxygen ◽  
Nerve Activity ◽  
Arterial Blood ◽  
Sustained Hypoxia

Sustained and episodic hypoxic exposures lead, by two different mechanisms, to an increase in ventilation after the exposure is terminated. Our aim was to investigate whether the pattern of hypoxia, cyclic or sustained, influences sympathetic activity and hemodynamics in the postexposure period. We measured sympathetic activity (peroneal microneurography), hemodynamics [plethysmographic forearm blood flow (FBF), arterial pressure, heart rate], and peripheral chemosensitivity in normal volunteers on two occasions during and after 2 h of either exposure. By design, mean arterial oxygen saturation was lower during sustained relative to cyclic hypoxia. Baseline to recovery muscle sympathetic nerve activity and blood pressure went from 15.7 ± 1.2 to 22.6 ± 1.9 bursts/min ( P < 0.01) and from 85.6 ± 3.2 to 96.1 ± 3.3 mmHg ( P < 0.05) after sustained hypoxia, respectively, but did not exhibit significant change from 13.6 ± 1.5 to 17.3 ± 2.5 bursts/min and 84.9 ± 2.8 to 89.8 ± 2.5 mmHg after cyclic hypoxia. A significant increase in FBF occurred after sustained, but not cyclic, hypoxia, from 2.3 ± 0.2 to 3.29 ± 0.4 and from 2.2 ± 0.1 to 3.1 ± 0.5 ml·min−1·100 g of tissue−1, respectively. Neither exposure altered the ventilatory response to progressive isocapnic hypoxia. Two hours of sustained hypoxia increased not only muscle sympathetic nerve activity but also arterial blood pressure. In contrast, cyclic hypoxia produced slight but not significant changes in hemodynamics and sympathetic activity. These findings suggest the cardiovascular response to acute hypoxia may depend on the intensity, rather than the pattern, of the hypoxic exposure.

scholarly journals Effects of transient intrathoracic pressure changes (hiccups) on systemic arterial pressure

1997 ◽  
Vol 83 (2) ◽  
pp. 371-375 ◽  
Author(s):  
Oommen P. Mathew
Keyword(s):  
Blood Pressure ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Systolic Blood Pressure ◽  
Cardiac Cycle ◽  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Intrathoracic Pressure ◽  
Systemic Arterial Pressure ◽  
Pressure Changes

Mathew, Oommen P. Effects of transient intrathoracic pressure changes (hiccups) on systemic arterial pressure. J. Appl. Physiol. 83(2): 371–375, 1997.—The purpose of the study was to determine the effect of transient changes in intrathoracic pressure on systemic arterial pressure by utilizing hiccups as a tool. Values of systolic and diastolic pressures before, during, and after hiccups were determined in 10 intubated preterm infants. Early-systolic hiccups decreased systolic blood pressure significantly ( P < 0.05) compared with control (39.38 ± 2.72 vs. 46.46 ± 3.41 mmHg) and posthiccups values, whereas no significant change in systolic blood pressure occurred during late-systolic hiccups. Diastolic pressure immediately after the hiccups remained unchanged during both early- and late-systolic hiccups. In contrast, diastolic pressure decreased significantly ( P < 0.05) when hiccups occurred during diastole (both early and late). Systolic pressures of the succeeding cardiac cycle remained unchanged after early-diastolic hiccups, whereas they decreased after late-diastolic hiccups. These results indicate that transient decreases in intrathoracic pressure reduce systemic arterial pressure primarily through an increase in the volume of the thoracic aorta. A reduction in stroke volume appears to contribute to the reduction in systolic pressure.

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