Metoprolol and Pindolol in Hypertension: Different Effects on Peripheral Haemodynamics

1981 ◽  
Vol 61 (s7) ◽  
pp. 425s-427s ◽  
Author(s):  
A. Svensson ◽  
T. Gudbrandsson ◽  
R. Sivertsson ◽  
L. Hansson
Keyword(s):  
Blood Pressure ◽  
Vascular Resistance ◽  
Reduce Blood Pressure ◽  
Peripheral Blood Flow ◽  
Sympathetic Stimulation ◽  
Maximal Dilatation ◽  
Double Blind ◽  
Muscle Work ◽  
Leg Muscle ◽  
The Difference

1. Thirty-six patients with essential hypertension, were randomly allocated to double-blind treatment with either metoprolol (100–200 mg/day) or pindolol (5–10 mg/day). The effects upon blood pressure and peripheral blood flow were determined. Both drugs reduced blood pressure significantly. 2. Heart rate was significantly reduced by metoprolol but not by pindolol. 3. Vascular resistance at maximal dilatation was not changed by either compound. 4. At rest, pindolol reduced vascular resistance in the calf by 14% (P < 0.05) but metoprolol tended to increase the resistance slightly. The difference in effect was also significant (P < 0.005). 5. During leg muscle work there were no changes in vascular resistance in the forearm with either compound. 6. We conclude that pindolol appears to reduce blood pressure at least partly through vascular mechanisms, in contrast to metoprolol. The response to sympathetic stimulation induced by physical exercise does not differ between metoprolol- and pindolol-treated patients.

The Effects of a Caffeine Placebo and Experimenter Expectation on Blood Pressure, Heart Rate, Well-Being, and Cognitive Performance

2001 ◽  
Vol 6 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Harald Walach ◽  
Stefan Schmidt ◽  
Yvonne-Michelle Bihr ◽  
Susanne Wiesch
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cognitive Task ◽  
Well Being ◽  
Control Group ◽  
Double Blind ◽  
Main Effect ◽  
The Difference ◽  
Being There ◽  
To Receive

We studied the effect of experimenter expectations and different instructions in a balanced placebo design. 157 subjects were randomized into a 2 × 4 factorial design. Two experimenters were led to expect placebos either to produce physiological effects or not (pro- vs. antiplacebo). All subjects except a control group received a caffeine placebo. They were either made to expect coffee, no coffee, or were in a double-blind condition. Dependent measures were blood pressure, heart rate, well-being, and a cognitive task. There was one main effect on the instruction factor (p = 0.03) with the group “told no caffeine” reporting significantly better well-being. There was one main effect on the experimenter factor with subjects instructed by experimenter “proplacebo” having higher systolic blood pressure (p = 0.008). There was one interaction with subjects instructed by experimenter “proplacebo” to receive coffee doing worse in the cognitive task than the rest. Subjects instructed by experimenter “antiplacebo” were significantly less likely to believe the experimental instruction, and that mostly if they had been instructed to receive coffee. Contrary to the literature we could not show an effect of instruction, but there was an effect of experimenters. It is likely, however, that these experimenter effects were not due to experimental manipulations, but to the difference in personalities.

scholarly journals Carbidopa for Afferent Baroreflex Failure in Familial Dysautonomia

Hypertension ◽  
2020 ◽  
Vol 76 (3) ◽  
pp. 724-731
Author(s):  
Lucy Norcliffe-Kaufmann ◽  
Jose-Alberto Palma ◽  
Jose Martinez ◽  
Horacio Kaufmann
Keyword(s):  
Blood Pressure ◽  
Blood Pressure Variability ◽  
Low Dose ◽  
Familial Dysautonomia ◽  
Reduce Blood Pressure ◽  
Catecholamine Release ◽  
High Dose ◽  
Double Blind ◽  
Adequate Treatment ◽  
Baroreflex Failure

Afferent lesions of the arterial baroreflex occur in familial dysautonomia. This leads to excessive blood pressure variability with falls and frequent surges that damage the organs. These hypertensive surges are the result of excess peripheral catecholamine release and have no adequate treatment. Carbidopa is a selective DOPA-decarboxylase inhibitor that suppresses catecholamines production outside the brain. To learn whether carbidopa can inhibit catecholamine-induced hypertensive surges in patients with severe afferent baroreflex failure, we conducted a double-blind randomized crossover trial in which patients with familial dysautonomia received high dose carbidopa (600 mg/day), low-dose carbidopa (300 mg/day), or matching placebo in 3 4-week treatment periods. Among the 22 patients enrolled (13 females/8 males), the median age was 26 (range, 12–59 years). At enrollment, patients had hypertensive peaks to 164/116 (range, 144/92 to 213/150 mm Hg). Twenty-four hour urinary norepinephrine excretion, a marker of peripheral catecholamine release, was significantly suppressed on both high dose and low dose carbidopa, compared with placebo ( P =0.0075). The 2 co-primary end points of the trial were met. The SD of systolic BP variability was reduced at both carbidopa doses (low dose: 17±4; high dose: 18±5 mm Hg) compared with placebo (23±7 mm Hg; P =0.0013), and there was a significant reduction in the systolic BP peaks on active treatment ( P =0.0015). High- and low-dose carbidopa were similarly effective and well tolerated. This study provides class Ib evidence that carbidopa can reduce blood pressure variability in patients with congenital afferent baroreflex failure. Similar beneficial effects are observed in patients with acquired baroreflex lesions.

Effects of Blood Pressure Reduction on the Structural Vascular Abnormality in Skin and Muscle Vascular Beds in Human Essential Hypertension

1976 ◽  
Vol 51 (s3) ◽  
pp. 77s-79s ◽  
Author(s):  
R. Sivertsson ◽  
L. Hansson
Keyword(s):  
Blood Pressure ◽  
Essential Hypertension ◽  
Vascular Resistance ◽  
Patient Group ◽  
Maximal Dilatation ◽  
Vascular Abnormality ◽  
Control Subjects ◽  
Vascular Beds ◽  
Hypertensive Therapy ◽  
Normotensive Control

1. Vascular resistance at maximal vasodilatation was examined in two vascular beds in two groups of hypertensive patients and in normotensive control subjects before and during anti-hypertensive therapy in the hypertension groups. 2. In one group of twelve untreated patients with essential hypertension, examined with plethysmography and intra-arterial blood pressure recording, a significantly higher vascular resistance at maximal vasodilatation was found in the hands compared with normotensive control subjects matched for age, sex, weight and height. This indicated a structural vascular abnormality in the patient group. 3. After 5 years of anti-hypertensive therapy in the patient group the difference in vascular resistance between patients and control subjects had decreased significantly, indicating a reversibility of the structural vascular abnormality. 4. Vascular resistance at maximal vasodilatation was examined in the calves of twelve untreated patients with essential hypertension and fourteen normotensive control subjects. Plethysmographic technique and indirect blood pressure recordings were used. A significantly higher vascular resistance was found in patients than in control subjects, indicating a structural vascular abnormality also in this vascular bed. 5. Anti-hypertensive treatment for 6 months in the patient group did not change vascular resistance at maximal dilatation, indicating that the structural vascular abnormality remained. 6. During acute reduction of blood pressure in hypertension by means of trimethaphan infusion, blood pressure and blood flow to the hands were reduced proportionally with no change of vascular resistance at maximal vasodilatation. 7. This indicates that resistance at maximal dilatation was unaffected by the acute reduction of blood pressure, in contrast to the findings after prolonged reduction of blood pressure in this vascular bed.

Haemodynamic and Neurohumoral Effects of Caffeine in Elderly Patients with Symptomatic Postprandial Hypotension: A Double-Blind, Randomized, Placebo-Controlled Study

1994 ◽  
Vol 87 (2) ◽  
pp. 259-267 ◽  
Author(s):  
Lewis A. Lipsitz ◽  
Rene W. M. M. Jansen ◽  
Carolyn M. Connelly ◽  
Margaret M. Kelley-Gagnon ◽  
Anthony J. Parker
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Elderly Patients ◽  
Blood Volume ◽  
Vascular Resistance ◽  
Controlled Study ◽  
Pathophysiological Mechanism ◽  
Double Blind ◽  
Postprandial Hypotension ◽  
Forearm Vascular Resistance

1. The aim of this study was to determine the effects of caffeine on haemodynamic and neurohumoral responses to meal ingestion in elderly patients with a history of symptomatic postprandial hypotension. 2. Postprandial hypotension is a common disorder of blood pressure regulation in the elderly, associated with falls and syncope. The pathophysiological mechanism is thought to be related to impaired vascular compensation for splanchnic blood pooling after a meal. Since caffeine inhibits vasodilatory adenosine receptors in the splanchnic circulation, we postulated that caffeine would reduce splanchnic blood pooling and prevent the development of postprandial hypotension. 3. We conducted a randomized, double-blind, placebo-controlled, cross-over study in nine elderly patients [age 76 ± 9 (SD) years] with histories of symptomatic postprandial hypotension. Standardized 1674 kJ liquid meals with 250 mg of caffeine or placebo were given on two occasions, at least 1 week apart. Blood pressure, heart rate, forearm vascular resistance (by venous occlusion plethysmography), and plasma caffeine and catecholamine levels were measured. Cardiac and splanchnic blood volume were determined by radionuclide scans. 4. By 30 min after both caffeine and placebo meal studies, supine mean arterial blood pressure fell significantly (P = 0.006) by 31 ± 7 and 19 ± 6 mmHg, respectively (mean ± SEM, between group difference was not significant). Heart rate, cardiac output and splanchnic blood volume increased significantly, but to a similar extent, after caffeine and placebo. Forearm vascular resistance was unchanged after both meals. 5. Oral caffeine given with a meal does not reduce splanchnic blood pooling nor prevent postprandial hypotension in symptomatic elderly patients.

Endogenous substance P modulates human cardiovascular regulation at rest and during orthostatic load

2007 ◽  
Vol 102 (6) ◽  
pp. 2092-2097 ◽  
Author(s):  
Matthew V. Dzurik ◽  
André Diedrich ◽  
Bonnie Black ◽  
Sachin Y. Paranjape ◽  
Satish R. Raj ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Substance P ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Muscle Sympathetic Nerve Activity ◽  
Cardiovascular Regulation ◽  
Postural Adjustment ◽  
Compensatory Mechanisms ◽  
Double Blind

Substance P (SP) is a peptide neurotransmitter identified in many central and peripheral neural pathways. Its precise role in human physiology has been difficult to elucidate. We used the selective neurokinin 1 (NK1) antagonist aprepitant as a pharmacological probe to determine the role of endogenous SP in human cardiovascular regulation. We performed a randomized, double-blind, placebo-controlled, crossover trial in healthy subjects. Blockade of endogenous NK1 receptors reduced resting muscle sympathetic activity 38% ( P = 0.002), reduced systemic vascular resistance by 25% ( P = 0.021), and increased cardiac index by 47% ( P = 0.006). This constellation of changes did not, however, alter either blood pressure or heart rate in the supine position. NK1 antagonism also raised orthostatic heart rate change by 38% ( P = 0.023), although during the incremental postural adjustment on the tilt table neither heart rate nor blood pressure was altered significantly. Despite a mildly attenuated vagal baroreflex with SP blockade, the depressor and pressor responses to nitroprusside and phenylephrine did not differ compared with placebo, suggesting other compensatory mechanisms. NK1 blockade manifests as a decrease in muscle sympathetic nerve activity and systemic vascular resistance. Our study suggests SP exerts a tonic enhancement of sympathetic outflow to some cardiovascular structures via its modulation of the NK1 receptor. Most likely, this ubiquitous neurotransmitter exerts effects at multiple sites that, in the aggregate, are relatively well compensated under many circumstances but may emerge with perturbations. This study is consistent with a role for SP afferents in supporting peripheral vascular resistance.

scholarly journals Dose-response effect of dietary nitrate on muscle contractility and blood pressure in older subjects: a pilot study

2020 ◽  
Author(s):  
Edgar J Gallardo ◽  
Derrick A Gray ◽  
Richard L Hoffman ◽  
Brandon A Yates ◽  
Ranjani N Moorthi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Knee Extensor ◽  
Optimal Dose ◽  
Reduce Blood Pressure ◽  
Older Individuals ◽  
Muscle Contractility ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Arterial Blood ◽  
Older Subjects

Abstract We have recently demonstrated that dietary nitrate, a source of nitric oxide (NO) via the nitrate → nitrite → NO enterosalivary pathway, can improve muscle contractility in healthy older men and women. Nitrate ingestion has also been shown to reduce blood pressure in some, but not all, studies of older individuals. However, the optimal dose for eliciting these beneficial effects is unknown. A pilot randomized, double-blind, placebo-controlled crossover study was therefore performed to determine the effects of ingesting 3.3 mL/kg of concentrated beetroot juice containing 0, 200, or 400 µmol/kg of nitrate in nine healthy older subjects (mean age 70±1 y). Maximal knee extensor power (Pmax) and speed (Vmax) were measured ~2.5 h after nitrate ingestion using isokinetic dynamometry. Blood pressure was monitored periodically throughout each study. Pmax (in W/kg) was higher (P<0.05) after the lower dose (3.9±0.4) compared to the placebo (3.7±0.4) or higher dose (3.7±0.4). Vmax (in rad/s) also tended to be higher (P=0.08) after the lower dose (11.9±0.7) compared to the placebo (10.8±0.8) or higher dose (11.2±0.8). Eight out of nine subjects achieved a higher Pmax and Vmax after the lower vs. the higher dose. These dose-related changes in muscle contractility generally paralleled changes in breath NO levels. No significant changes were found in systolic, diastolic, or mean arterial blood pressure. A lower dose of nitrate increases muscle speed and power in healthy older individuals, but these improvements are lost at a higher dose. Blood pressure, on the other hand, is not reduced even with a higher dose.

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