Effect of Age on Vascular α-Adrenoceptor Responsiveness in Man

1982 ◽  
Vol 63 (s8) ◽  
pp. 305s-308s ◽  
Author(s):  
Henry L. Elliott ◽  
David J. Sumner ◽  
Kathleen McLean ◽  
Peter C. Rubin ◽  
John L. Reid
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Pressure ◽  
The Elderly ◽  
Elderly Subjects ◽  
Comparable Amount ◽  
Healthy Elderly ◽  
Age Related ◽  
Significant Difference ◽  
Mean Heart Rate

1. The responsiveness of α-receptors was compared in six young and six healthy elderly subjects by evaluating the haemodynamic effects of the a, antagonist prazosin and the pressor responses to the a, agonist phenylephrine. 2. Oral prazosin (1 mg) lowered erect (but not supine) blood pressure in both groups by a comparable amount: in young and old groups the respective maximal falls in systolic pressure were 19.5 ± 15.7 and 29.3 ± 11.4 mmHg (mean ± sd) and for diastolic pressure the maximal falls were 13 ± 13.3 and 18 ± 11.1 mmHg. 3. This similar fall in blood pressure occurred in association with a significantly different heart rate response: in the young group mean heart rate increased to 103 beats/min but there was no corresponding increase in the elderly group, which had a mean heart rate of 80 beats/min. 4. Log dose-response curves were derived from incremental intravenous infusions of phenylephrine, and the doses required to raise mean arterial pressure by 20 mmHg (PD20) were compared: the mean PD20 was significantly different in the two groups: 2.5 ± 1.6 in the young compared with 4.6 ± 2.3 μg min−1 kg−1 in the elderly, consistent with reduced pressor responsiveness in the elderly. 5. No significant difference in PD20 was apparent when pressor responsiveness was determined after prazosin, but the elderly required a significantly smaller increase in phenylephrine dosage to overcome prazosin's α-receptor-blocking effects. 6. Although there is no evidence of an age-related increase in the sensitivity of α-adrenoceptor-mediated vasoconstriction, the results are not inconsistent with an age-related reduction in α-adrenoceptor responsiveness.

Effect of ‘Autonomic Blockade’ on Cardiac β-Adrenergic Chronotropic Responsiveness in Healthy Young, Healthy Elderly and Endurance-Trained Elderly Subjects

1994 ◽  
Vol 87 (3) ◽  
pp. 297-302 ◽  
Author(s):  
G. A. Ford ◽  
O. F. W. James
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Geometric Mean ◽  
Cardiovascular Responses ◽  
The Elderly ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Age Related ◽  
Autonomic Blockade ◽  
Young Subjects

1. Cardiac chronotropic responses to isoprenaline are reduced with ageing in man. It is unclear whether this is due to reduced cardiac β-adrenergic sensitivity or to age-associated differences in reflex cardiovascular responses to the vasodilatory effects of isoprenaline. Age-associated changes in physical activity are also reported to influence β-adrenergic sensitivity. 2. The aim of the present study was to determine the contribution of alterations in reflex changes in parasympathetic and sympathetic influences and physical fitness to the age-associated reduction in cardiac chronotropic responses to β-adrenergic agonists. 3. The effect of ‘autonomic blockade’ with atropine (40 μg/kg intravenously) and clonidine (4 μg/kg intravenously) on blood pressure, heart rate and chronotropic responses to intravenous bolus isoprenaline doses was determined in eight healthy young (mean age 21 years), nine healthy elderly (72 years) and 10 endurance-trained elderly (69 years) subjects. 4. Elderly subjects had a reduced increase in heart rate after atropine (young, 49 ± 9 beats/min; elderly, 36 ± 5 beats/min; endurance-trained elderly, 34 ± 12 beats/min; P < 0.01) and did not demonstrate the transient increase in systolic blood pressure after clonidine observed in young subjects (young, 11 ± 10 mmHg; elderly, −12 ± 16 mmHg; endurance-trained elderly, −18 ± 11 mmHg; P < 0.01). 5. Cardiac chronotropic sensitivity to isoprenaline after ‘autonomic blockade’ increased in the young but decreased in the elderly subjects. The isoprenaline dose that increased heart rate by 25 beats/min before and after autonomic blockade' was: young, before 1.6 μg, after 2.8 μg, P < 0.01 (geometric mean, paired test); elderly, before 6.9 μg, after 3.6 μg, P < 0.05; endurance-trained elderly, before 5.9 μg, after 4.0 μg, P < 0.05. Cardiac chronotropic sensitivity to isoprenaline was significantly reduced in elderly compared with young subjects before (P < 0.01) but was similar after (P = 0.09) ‘autonomic blockade’. Chronotropic sensitivity did not differ between healthy and endurance-trained elderly subjects before or after ‘autonomic blockade’. 6. The age-associated reduction in cardiac chronotropic responses to bolus isoprenaline is primarily due to an age-related reduction in the influence of reflex cardiovascular responses on heart rate and not to an age-related reduction in cardiac β-adrenergic sensitivity. Endurance training is not associated with altered β-adrenergic chronotropic sensitivity in the elderly. The transient pressor response to intravenously administered clonidine may be lost in ageing man.

Decreased Neutrophil Cyclic AMP Response to Isoprenaline Stimulation in the Elderly

1983 ◽  
Vol 65 (2) ◽  
pp. 155-157 ◽  
Author(s):  
T. G. Cotter ◽  
K. O'Malley
Keyword(s):  
Monoclonal Antibodies ◽  
Cyclic Amp ◽  
The Elderly ◽  
Population Heterogeneity ◽  
Elderly Subjects ◽  
Age Related ◽  
Significant Difference ◽  
Young Subjects ◽  
Drug Free

1. Neutrophils from drug-free elderly subjects produced approximately 50% less cyclic AMP in response to isoprenaline than did neutrophils from young subjects. A significant difference in basal cyclic AMP levels was also evident (elderly 2.8 ± 0.37; young 4.9 ± 0.36 pmol of cAMP/107 cells; P < 0.05). 2. With a range of anti-neutrophil monoclonal antibodies no evidence of age-related neutrophil population heterogeneity was found. 3. These findings indicate that the age-related decline in β-adrenoceptor responsiveness is not due to changes in the neutrophil population. 4. The present results support the hypothesis that there is a generalized decline in β-adrenoceptor-mediated responsiveness in the elderly.

Campodimele Study: Blood Pressure and Heart Rate Pattern in Clinically Healthy Elderly Subjects

1994 ◽  
Vol 11 (6) ◽  
pp. 381-392 ◽  
Author(s):  
P. Cugini ◽  
G. Leone ◽  
P. Lucia ◽  
F. A. Sepe ◽  
A. Pelosio ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Heart Rate Pattern ◽  
Healthy Elderly Subjects

scholarly journals Etorphine-halothane anaesthesia in two five-year-old African elephants (Loxodonta africana) : clinical communication

1999 ◽  
Vol 70 (4) ◽  
Author(s):  
G.F. Stegmann
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Pressure ◽  
Loxodonta Africana ◽  
African Elephants ◽  
Clinical Communication ◽  
Dental Surgery ◽  
Blood Pressures ◽  
The Mean ◽  
Mean Heart Rate

Anaesthesia of 2 five-year-old femaleAfrican elephants (Loxodonta africana) was required for dental surgery. The animals were each premedicated with 120 mg of azaperone 60 min before transportation to the hospital. Before offloading, 1 mg etorphine was administered intramuscularly (i.m.) to each elephant to facilitate walking them to the equine induction / recovery room. For induction, 2 mg etorphine was administered i.m. to each animal. Induction was complete within 6 min. Surgical anaesthesia was induced with halothane-in-oxygen after intubation of the trunk. During surgery the mean heart rate was 61 and 45 beats / min respectively. Systolic blood pressures increased to 27.5 and 25.6 kPa respectively, and were treated with intravenous azaperone. Blood pressure decreased thereafter to a mean systolic pressure of 18.1 and 19.8 kPa, respectively. Rectal temperature was 35.6 and 33.9 oC at the onset of surgery, and decreased to 35.3 and 33.5 oC, respectively, at the end of anaesthesia. Etorphine anaesthesia was reversed with 5mg diprenorphine at the completion of 90 min of surgery.

scholarly journals Arginine behaviour after arginine or citrulline administration in older subjects

2015 ◽  
Vol 115 (3) ◽  
pp. 399-404 ◽  
Author(s):  
C. Moinard ◽  
J. Maccario ◽  
S. Walrand ◽  
V. Lasserre ◽  
J. Marc ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
The Elderly ◽  
Volume Of Distribution ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Age Related ◽  
Loading Tests ◽  
Kinetics Of ◽  
Healthy Elderly Subjects

AbstractArginine (ARG) and its precursor citrulline (CIT) are popular dietary supplements, especially for the elderly. However, age-related reductions in lean body mass and alterations in organ functions could change their bioavailability. Pharmacokinetics and tolerance to amino acid (AA) loads are poorly documented in elderly subjects. The objective here was to characterise the plasma kinetics of CIT and ARG in a single-dosing study design. Eight fasting elderly men underwent two separate isomolar oral loading tests (10 g of CIT or 9·94 g of ARG). Blood was withdrawn over an 8-h period to measure plasma AA concentrations. Only CIT, ornithine and ARG plasma concentrations were changed. Volume of distribution was not dependent on AA administered. Conversely, parameters related to ARG kinetics were strongly dependent on AA administered: after ARG load, elimination was higher (ARG>CIT; P=0·041) and admission period+time at peak concentration was lower (ARG<CIT; P=0·033), and the combination of both phenomena results in a marked increase in ARG availability when CIT was administered (ARG<CIT; P=0·033) compared with ARG administration itself. In conclusion, a single CIT administration in the elderly is safe and well tolerated, and CIT proves to be a better in vivo ARG precursor than ARG itself in healthy elderly subjects.

Orthostatic Circulatory Control in the Elderly Evaluated by Non-Invasive Continuous Blood Pressure Measurement

1990 ◽  
Vol 79 (1) ◽  
pp. 73-79 ◽  
Author(s):  
B. P. M. Imholz ◽  
J. H. A. Dambrink ◽  
J. M. Karemaker ◽  
W. Wieling
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Time Course ◽  
Blood Pressure Measurement ◽  
Elderly Subjects ◽  
Postural Changes ◽  
Significant Difference ◽  
Head Up Tilt ◽  
Blood Pressures

1. Continuous orthostatic responses of blood pressure and heart rate were measured in 40 healthy and active elderly subjects over 70 years of age in order to assess the time course and rapidity of orthostatic cardiovascular adaptation in old age. 2. During the first 30 s (initial phase) the effects of active standing and passive head-up tilt closely resembled those observed earlier in younger age groups. Standing up was accompanied by a drop (mean ± SD) in systolic and diastolic blood pressures of 26 ± 13 mmHg and 12 ± 18 mmHg, respectively, at around 10 s, and a subsequent rise up to 11 ± 17 mmHg and 8 ± 6 mmHg above supine values at around 20 s. The drop in blood pressure upon standing was accompanied by a transient increase in heart rate with a maximum of 13 beats/min, followed by a gradual decrease to 7 beats/min above supine levels. These characteristic transient changes were absent upon a passive head-up tilt. 3. After 1–2 min of standing (early steady-state phase) diastolic blood pressure and heart rate increased significantly after active and passive postural changes. On average, for all subjects systolic blood pressure tended to increase from control during 5–10 min standing, reaching a significant difference at 10 min. During standing, the largest increases in systolic blood pressure were found in subjects with the lowest supine blood pressures. 4. In conclusion, for the investigation of orthostatic circulatory responses in elderly subjects the following factors have to be taken into account: active versus passive changes in posture, the timing of the blood pressure reading, and the level of supine blood pressure.

scholarly journals The hypotensive response to oral fat is comparable but slower compared with carbohydrate in healthy elderly subjects

2006 ◽  
Vol 95 (2) ◽  
pp. 340-345 ◽  
Author(s):  
Renuka Visvanathan ◽  
Michael Horowitz ◽  
Ian Chapman
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Area Under The Curve ◽  
Elderly Subjects ◽  
High Fat ◽  
Postprandial Hypotension ◽  
Healthy Elderly ◽  
Hypotensive Response ◽  
Healthy Elderly Subjects

The objective of the present study was to determine the comparative hypotensive responses to drinks containing predominantly fat and carbohydrate (CHO) in healthy elderly subjects. Using a randomised, cross-over study, the participants, twelve elderly subjects, six of them female (72·2 (sd 5·7) years), were investigated. On three separate days, blood pressure (BP) and heart rate were measured following ingestion of 300ml drinks containing: (1) CHO (75g glucose and 93g Polyjoule (CHO polymer) providing 2732kJ (653kcal)); (2) 88% fat (cream blended with milk providing 2732kJ (653kcal)); (3) water. Systolic BP decreased following the CHO drink (P<0·001) and the high-fat drink (P<0·001) but not water; there was no difference in the magnitude of the decrease between the CHO drink and the drink containing fat (13·4v. 15·6mmHg). However, the onset of the fall was slower after the fat-containing drink (13·0v. 26·5min (P=0·01); area under the curve for 0–30min for CHO drink −6·5v. fat-containing drink 125·4 mmHg×min (P=0·043)). We conclude that ingestion of a high-fat drink results in a comparable fall in BP to a CHO drink although the onset is relatively slower. These observations may have implications for the management of postprandial hypotension.

Disparities in circulatory adjustment to standing between young and elderly subjects explained by pulse contour analysis

1992 ◽  
Vol 83 (2) ◽  
pp. 149-155 ◽  
Author(s):  
W. Wieling ◽  
D. P. Veerman ◽  
J. H. A. Dambrink ◽  
B. P. M. Imholz
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Total Peripheral Resistance ◽  
Age Groups ◽  
Peripheral Resistance ◽  
The Elderly ◽  
Pulse Contour ◽  
Elderly Subjects ◽  
Orthostatic Stress ◽  
Young Subjects

1. The circulatory adjustment to standing was investigated in two age groups. Young subjects consisted of 20 healthy 10–14-year-old girls and boys. Elderly subjects consisted of 40 70–86-year-old healthy and active females and males. Continuous responses of blood pressure and heart rate were recorded by Finapres. A pulse contour algorithm applied to the finger arterial pressure waveform was used to assess stroke volume responses. 2. During the first 30 s (initial phase), an almost identical drop in mean blood pressure was found in both age groups (young, 16 ± 10 mmHg; old, 17 ± 10 mmHg), but the initial heart rate increase was attenuated in the elderly subjects (young, 29 ± 7 beats/min; old, 17 ± 7 beats/min). 3. During the period from 30 s to 10 min of standing, mean blood pressure increased from 96 ± 12 to 106 ± 12 mmHg in the elderly subjects compared with almost no change in the young subjects (from 82 ± 8 to 84 ± 7 mmHg). In the elderly subjects a progressive increase in total peripheral resistance (from 114 ± 14% to 146 ± 29%) was found, compared with an initial rapid increase in total peripheral resistance (126 ± 18% after 30 s) with no further change during prolonged standing (124 ± 17% after 10 min) in the young subjects. In this age group the decrease in stroke volume and the increase in heart rate after 10 min of standing were large (young, −37 ± 11% and 27 ± 11 beats/min; old, −31 ± 9% and 7 ± 6 beats/min, respectively). 4. In conclusion, young subjects adjust to orthostatic stress mainly by a marked increase in heart rate. In healthy elderly subjects an attenuation of the heart rate response during orthostatic stress is compensated by a pronounced increase in total peripheral resistance resulting in an increase in blood pressure.

scholarly journals Renal functional reserve in healthy elderly subjects.

1993 ◽  
Vol 3 (7) ◽  
pp. 1371-1377
Author(s):  
D Fliser ◽  
M Zeier ◽  
R Nowack ◽  
E Ritz
Keyword(s):  
Renal Disease ◽  
The Elderly ◽  
Renal Hemodynamics ◽  
Elderly Subjects ◽  
Functional Reserve ◽  
Renal Functional Reserve ◽  
Healthy Elderly ◽  
Age Related ◽  
Before And After ◽  
Young Subjects

The increase in GFR after an amino acid (AA) load, the so-called renal functional reserve, is impaired in the aged rat. Whether the renal functional reserve predicts the progression of renal disease in humans is controversial, but it is possible that age-related alterations of renal hemodynamics are relevant for the evolution of renal disease in the elderly. We compared renal hemodynamics before and after an AA infusion in 15 healthy normotensive subjects of young age (seven women, eight men; median age, 26 yr; range, 23 to 32) and in 10 subjects of old age (six women, four men; median age, 70 yr; range, 61 to 82) on normal dietary protein intake. Baseline GFR and effective RPF were measured after 12 h of fasting by the inulin (Cin) and para-aminohippurate (Cpah) steady-state infusion techniques. The renal functional reserve was examined after an overnight AA infusion (7% solution; 83 mL/h). Median basal Cin and Cpah were significantly lower (P < 0.01) in the elderly (102 and 339 mL/min per 1.73 m2) than in the young subjects (122 and 647 mL/min per 1.73 m2), but virtually all GFR values of the elderly were still within the normal range. Median Cin upon infusion of AA was 118 mL/min per 1.73 m2 (range, 98 to 137) in the elderly and 146 (range, 120 to 171) in the young, respectively. Corresponding values of Cpah were 349 mL/min per 1.73 m2 in the elderly versus 689 mL/min per 1.73 m2 in the young. Cin increased significantly (P < 0.01) after the AA load in both young and elderly subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

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