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.

scholarly journals Extra Virgin Olive Oil Prevents the Age-Related Shifts of the Distribution of HDL Subclasses and Improves Their Functionality

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2235
Author(s):  
Alyann Otrante ◽  
Amal Trigui ◽  
Roua Walha ◽  
Hicham Berrougui ◽  
Tamas Fulop ◽  
...  
Keyword(s):  
Olive Oil ◽  
Virgin Olive Oil ◽  
Density Lipoprotein ◽  
Extra Virgin Olive Oil ◽  
The Elderly ◽  
High Density ◽  
Lipoprotein Cholesterol ◽  
Elderly Subjects ◽  
Age Related ◽  
Young Subjects

High-density lipoproteins (HDL) maintain cholesterol homeostasis through the role they play in regulating reverse cholesterol transport (RCT), a process by which excess cholesterol is transported back to the liver for elimination. However, RCT can be altered in the presence of cardiovascular risk factors, such as aging, which contributes to the increase in the incidence of cardiovascular diseases (CVD). The present study was aimed at investigating the effect of extra virgin olive oil (EVOO) intake on the cholesterol efflux capacity (CEC) of HDL, and to elucidate on the mechanisms by which EVOO intake improves the anti-atherogenic activity of HDL. A total of 84 healthy women and men were enrolled and were distributed, according to age, into two groups: 27 young (31.81 ± 6.79 years) and 57 elderly (70.72 ± 5.6 years) subjects. The subjects in both groups were given 25 mL/d of extra virgin olive oil (EVOO) for 12 weeks. CEC was measured using J774 macrophages radiolabeled with tritiated cholesterol ((3H) cholesterol). HDL subclass distributions were analyzed using the Quantimetrix Lipoprint® system. The HDL from the elderly subjects exhibited a lower level of CEC, at 11.12% (p < 0.0001), than the HDL from the young subjects. The CEC of the elderly subjects returned to normal levels following 12 weeks of EVOO intake. An analysis of the distribution of HDL subclasses showed that HDL from the elderly subjects were composed of lower levels of large HDL (L-HDL) (p < 0.03) and higher levels of small HDL (S-HDL) (p < 0.002) compared to HDL from the young subjects. A multiple linear regression analysis revealed a positive correlation between CEC and L-HDL levels (r = 0.35 and p < 0.001) as well as an inverse correlation between CEC and S-HDL levels (r = −0.27 and p < 0.01). This correlation remained significant even when several variables, including age, sex, and BMI as well as low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and glucose levels (β = 0.28, p < 0.002, and β = 0.24, p = 0.01) were accounted for. Consuming EVOO for 12 weeks modulated the age-related difference in the distribution of HDL subclasses by reducing the level of S-HDL and increasing the level of intermediate-HDL/large-HDL (I-HDL/L-HDL) in the elderly subjects. The age-related alteration of the CEC of HDL was due, in part, to an alteration in the distribution of HDL subclasses. A diet enriched in EVOO improved the functionality of HDL through an increase in I-HDL/L-HDL and a decrease in S-HDL.

scholarly journals POS1288 TUBERCULOUS SPONDYLODISCITIS IN ELDERLY: EPIDEMIOLOGY, CLINICAL, FEATURES, TREATMENT AND OUTCOMES

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 926.1-926
Author(s):  
M. Mrabet ◽  
S. Boussaid ◽  
S. Jemmali ◽  
H. Sahli ◽  
H. Ajlani ◽  
...  
Keyword(s):  
Clinical Features ◽  
The Elderly ◽  
Lumbar Pain ◽  
Elderly Subjects ◽  
Normocytic Anemia ◽  
Imaging Features ◽  
X Rays ◽  
Significant Difference ◽  
Young Subjects ◽  
Tuberculous Spondylodiscitis

Background:Tuberculosis is still endemic all over the world. The incidence of tuberculous spondylodiscitis (TS) is steadily increasing. Clinical features and outcomes of this affection are various and depending on various parameters, including age.Objectives:Our objective was to explore the differences in presentation and the results of further investigations and the prognosis of TS between young and elderly subjects.Methods:We conduct a retrospective and descriptive study in a single rheumatology department. Data were collected from files of patients hospitalized in the past 20 years (2000-2020) who have been diagnosed with TS. We carried out a comparative study concerning the clinical biological, imaging features and outcomes between young subjects and subjects aged over 65 years.Results:Fifty-two cases of TS were collected (37F/15M). The mean age of the population was 55.21 years ± 17.79 [19-91]. Thirty-three patients (69.2%) were classified as young versus 16 elderly patients (30.8%), with female predominance in both groups (69.4% and 75% respectively, p = 0.57). Young subjects was more frequently vaccinated (88.9%) by Bacillus Calmette–Guérin (BCG) (p < 0.001). A delayed diagnosis was noted in both groups (p = 0.24). Lumbar spine involvement was the most common (57.7%). In the two age ranges, the onset of the disease was progressive (p = 0.22), characterized by segmental spine stiffness (p = 0.57) and lumbar pain with general signs (p = 0.27), such as: impaired general condition, fever, night sweats and weight loss. Biological inflammatory syndrome and normochrome normocytic anemia were encountered in both cases (p = 0.08 and p = 0.2, respectively). Standard X-rays and Computed tomography were more performed in young subjects (94.4% and 69.4%, respectively; p < 0.001), unlike magnetic resonance imaging which was more common in elderly subjects but with no statistically significant difference (p = 0.22). Disc pinch, erosion of vertebral plateaus and vertebral collapse were the major signs (82.7%, 65.4% and 67.3%, respectively). Clinical, biological and imaging arguments contributed to positive diagnosis in both groups (p = 0.24). Common medical treatment was anti-tuberculosis: Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), Ethambutol (E) and physical treatment such as immobilization witch was more common in the eldery (56.3%, p = 0.16). The evolution of the disease was characterized by a clear improvement of young subjects during the second week of treatment (p < 0.001). A more frequent clinical improvement in older subjects was during the fourth week but with no statistically significant difference (p = 0.13). The occurrence of immediate complications was more frequent in the elderly (p = 0.23) with a predominance for drug complications (56.3%) such as: hepatic cytolysis (12.5%), hyperuricemia (18.8%) and major intolerance to anti-tuberculosis (18.8%).Conclusion:TS is a frequent condition that needs to be treated rapidly. the clinical presentation of TS in the elderly is less noisy which leads to more frequent complications and mortality.Disclosure of Interests:None declared

scholarly journals Age-related changes in multifinger synergies in accurate moment of force production tasks

2007 ◽  
Vol 102 (4) ◽  
pp. 1490-1501 ◽  
Author(s):  
Halla Olafsdottir ◽  
Wei Zhang ◽  
Vladimir M. Zatsiorsky ◽  
Mark L. Latash
Keyword(s):  
Hand Function ◽  
The Elderly ◽  
Time Profile ◽  
Uncontrolled Manifold ◽  
Elderly Subjects ◽  
Total Force ◽  
Dominant Hand ◽  
Total Moment ◽  
Age Related ◽  
Young Subjects

The purpose of this investigation was to document and quantify age-related differences in the coordination of fingers during a task that required production of an accurate time profile of the total moment of force by the four fingers of a hand. We hypothesized that elderly subjects would show a decreased ability to stabilize a time profile of the total moment of force, leading to larger indexes of moment variability compared with young subjects. The subjects followed a trapezoidal template on a computer screen by producing a time profile of the total moment of force while pressing down on force sensors with the four fingers of the right (dominant) hand. To quantify synergies, we used the framework of the uncontrolled manifold hypothesis. The elderly subjects produced larger total force, larger variance of both total force and total moment of force, and larger involvement of fingers that produced moment of force against the required moment direction (antagonist moment). This was particularly prominent during supination efforts. Young subjects showed covariation of commands to fingers across trials that stabilized the moment of total force (moment-stabilizing synergy), while elderly subjects failed to do so. Both subject groups showed similar indexes of covariation of commands to the fingers that stabilized the time profile of the total force. The lack of moment-stabilizing synergies may be causally related to the documented impairment of hand function with age.

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.

scholarly journals AB0938 PARTICULARITIES OF INFECTIOUS SPONDYLODISCITIS IN THE ELDERLY: COMPARATIVE STUDY WITH THE YOUNG SUBJECT

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1768.2-1768
Author(s):  
L. Ben Ammar ◽  
A. Ben Tekaya ◽  
M. Ben Hammamia ◽  
O. Saidane ◽  
S. Bouden ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Compression ◽  
Cauda Equina ◽  
The Elderly ◽  
Cord Compression ◽  
Elderly Subjects ◽  
Significant Difference ◽  
Infectious Spondylodiscitis ◽  
Older Subjects ◽  
Young Subjects

Background:The incidence of infectious spondylodiscitis is steadily increasing. The prognosis depends on various parameters, including age.Objectives:To explore the differences in presentation and the results of further investigations and the prognosis of spondylodiscitis between young and elderly subjects.Methods:This is a retrospective study of 113 patients admitted to our department over a period of 20 years [1998-2018]. The epidemiological, clinical, biological, radiological and progressive aspects of spondylodiscitis in subjects over the age of 65 were compared to cases of spondylodiscitis in young subjects whose age is less than 65 years.Results:Of the 113 identified patients, 33 (29.2%) were classified as older, with male predominance in both groups (56.2 and 51.5% respectively; p=0.6). The presence of risk factors, particularly diabetes, was more frequent in the older subjects but without a statistically significant difference (p=0.2). Hepathopathies were also more frequent in the elderly but without statistically significant difference (p=0.3). The mean duration of progression was 3 months with no statistically significant difference between the two groups (4 and 5 months respectively, p=0.1).The presence of neurological symptoms, especially radiculalgia, was more frequently reported in younger subjects (p=0.01). Also, young subjects were more likely to have a fever (p=0.005). On the other hand, a biological inflammatory syndrome was more frequently encountered in older subjects (p=0.03).We found no statistically significant difference in the location of spondylodiscitis (p=0.4). Also, multifocal involvement was more frequent in older subjects but without a statistically significant difference.Radiologically, para-vertebral abscesses, epiduritis and spinal cord compression were more common in the elderly group (p=0.03; p=0.01 and p=0.01, respectively). While the frequency of intervertebral pinching and erosions was similar in both groups (p=0.1; p=0.8, respectively).Tuberculosis was the most involved germ in more than 50% of cases with no statistically significant difference between the two groups (57.5 and 51.5% respectively; p=0.5).All patients received targeted antibiotic therapy.The occurrence of immediate complications was more frequent in the elderly but without a statistically significant difference (p=0.1). They included neurological complications (spinal cord compression and Cauda equina syndrome) that occurred in 6.3% of cases in younger subjects versus 36.4% of cases in the elderly (p=0.07). Followed by treatment side effects dominated by disturbance of liver function due mainly to antituberculosis drugs occurring in 16.3% of cases in the younger group and 15.2% of cases in older subjects (p=0.8). Finally, there were 2 deaths in each group (p=0.5).Conclusion:Our series has shown that the picture of spondylodiscitis in the elderly is less noisy. However, the neurological damage is more pronounced on imaging. The misleading symptomatology in the elderly explains the delay in diagnosis and treatment, which leads to more frequent complications and excess mortality.Disclosure of Interests:None declared

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.

scholarly journals Sonoelastographıc assessment of the age-related changes of the Achilles tendon

2015 ◽  
Vol 17 (1) ◽  
pp. 58 ◽  
Author(s):  
Aynur Turan ◽  
Mehmet Akif Teber ◽  
Zeynep Ilerisoy Yakut ◽  
Havva Akmaz Unlu ◽  
Baki Hekimoglu
Keyword(s):  
The Elderly ◽  
The Body ◽  
Elderly Subjects ◽  
Reference Tissue ◽  
Traumatic Injuries ◽  
Age Related ◽  
High Prevalence ◽  
History Of ◽  
Radiologic Investigation ◽  
Young Subjects

Aims: Tendons are crucial for optimal muscle force transfer and subject to changes with aging which may impair func- tional ability of elderly individuals. Achilles is the largest and the strongest tendon in the body; therefore it is an excellent site for the radiologic investigation of aging of tendons. Sonoelastography (SE) is a new ultrasound-based imaging technique that provides information on elastic properties and stiffness of tissues. The aim of our study was to investigate the age-related alterations in Achilles tendons using SE. Material and methods: Forty five geriatric (age≥ 65 years) and 42 young (age 18-40 years) healthy consecutive subjects were enrolled. Subjects with known history of metabolic or endocrine diseases, sports or traumatic injuries, peripheral vascular disorders were excluded. Both Achilles tendons were scanned with a real-time SE probe at a frequency of 6–15 MHz. Strains of Achilles tendons’ proximal, middle and distal parts were assessed semi-quantitatively with comparing a reference tissue. Results: Both SE methods -color coded evaluation and strain measurement- showed a re- markably stiffer tendon in the elderly subjects compared to young subjects in all thirds of Achilles tendons. In young subjects 84.9 % tendon thirds were blue, and 15.1% were green whereas, in elders 93.7% were blue and 6.3% were green (p=0.024). There was a significant correlation between age and stiffness of tendons assessed with strain indices. Conclusion: Our result showed increased tendon stiffness in elderly subjects which might be responsible for the high prevalence of Achilles tendi- nopathies observed in elderly subjects.

scholarly journals Elderly people are inherently sensitive to the pharmacological activity of rivaroxaban: implications for DOAC prescribing

2020 ◽  
Author(s):  
Emmanouela Kampouraki ◽  
Salah Abohelaika ◽  
Peter Avery ◽  
Tina Biss ◽  
Paul Murphy ◽  
...  
Keyword(s):  
Elderly Patients ◽  
Prothrombin Time ◽  
Pharmacological Activity ◽  
Ex Vivo ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
The Elderly ◽  
Elderly Subjects ◽  
Age Related ◽  
Young Subjects

Abstract According to both trial and clinical data on direct oral anticoagulants (DOACs) elderly patients are at greatest risk of bleeding. It is unclear whether age intrinsically affects anticoagulation response. To investigate the age-related sensitivity to DOACs, we compared the pharmacological activity of the direct factor Xa inhibitor, rivaroxaban, between young and elderly subjects ex-vivo. 36 fit elderly and 30 fit young subjects [median (IQR) age: 83(75–87) vs 30(26–38) years] provided a blood sample. Clotting parameters were measured in the resultant plasma samples incubated with rivaroxaban (100–500 ng/ml). Parametric, non-parametric tests and regression lines adjusted for rivaroxaban concentration and baseline values were used to compare data. Rivaroxaban produced a greater prolongation of both Prothrombin Time (PT) and modified Prothrombin Time (mPT) (both p < 0.001) in the elderly compared to young subjects (with difference in mean PT increasing from 1.6 to 6.1s and for mPT from 23.5 to 71.1s at 100 ng/ml and 500 ng/ml plasma rivaroxaban concentration, respectively). Factor X and factor II activity was significantly lower in the elderly in the presence of rivaroxaban (p < 0.001 for both). Rivaroxaban prolonged time-based parameters and suppressed the amount of thrombin generation to a significantly greater extent in the elderly compared to young subjects [%change from baseline for Endogenous Thrombin Potential (ETP): − 35.0 ± 4.4 vs − 29.8 ± 7.4 nM*min; p = 0.002]. The use of validated DOAC assays will be of considerable benefit for monitoring elderly patients who, because of their increased sensitivity to rivaroxaban, may require lower doses of the drug for therapeutic anticoagulation.

Aging: Sensitivity vs Criterion in Taste Perception

1983 ◽  
Vol 6 (1) ◽  
pp. 105-115
Author(s):  
T. Kushnir ◽  
N. Shapira
Keyword(s):  
Strategic Behavior ◽  
Tap Water ◽  
Detection Threshold ◽  
Threshold Level ◽  
The Elderly ◽  
False Positives ◽  
Taste Perception ◽  
Elderly Subjects ◽  
Age Related ◽  
Young Subjects

The study employed the signal-detection paradigm as a model for investigating age related biological vs cognitive (decision) effects on perceptual behavior. Old and young subjects reported the presence or absence of sugar in threshold level solutions and tap water. It was found that the aged subjects displayed a higher detection threshold. They also obtained a higher (stricter) criterion of decision, fewer false-positives and a greater false-negatives-to-total-errors ratio. These findings were interpreted as strategic behavior motivated by the elderly subjects' greater need to perform well through reducing the error rate. A post-hoc interview found that most subjects equated the term 'error' with false-positives only. Therefore, the negative response bias found among the elderly subjects may represent a strategic attempt to reduce the rate of false-positive errors. It is also speculated that it may reflect a need to save energy, since negative responses imply an unwillingness to commit oneself to exert effort.

Regulation of venous alpha-adrenergic responses in older humans

1991 ◽  
Vol 260 (4) ◽  
pp. E599-E607 ◽  
Author(s):  
M. A. Supiano ◽  
R. V. Hogikyan ◽  
A. M. Stoltz ◽  
N. Orstan ◽  
J. B. Halter
Keyword(s):  
The Elderly ◽  
Elderly Subjects ◽  
Response Analysis ◽  
Plasma Norepinephrine ◽  
Detectable Change ◽  
Adrenergic Agonist ◽  
Age Related ◽  
Adrenergic Response ◽  
Young Subjects ◽  
Related Increase

Decreased adrenergic responsiveness in human aging could be a result of downregulation mediated by the age-related increase in sympathetic nervous system (SNS) tone. If so, suppression of SNS tone in elderly subjects should upregulate adrenergic responsiveness into the range observed for younger subjects. To test this hypothesis, we examined alpha 1 (phenylephrine)- and alpha 2 (clonidine)-adrenergic agonist-mediated venoconstriction in a group of 15 older healthy subjects (age 59-73 yr) during placebo and when SNS tone was suppressed by guanadrel (15 mg twice daily for 3 wk). During guanadrel compared with placebo 1) there were decreases in plasma norepinephrine (NE) levels (1.47 +/- 0.07 to 0.80 +/- 0.06 nM; P less than 0.001) and in the extravascular NE release rate derived from [3H]NE kinetics (11.8 +/- 1.4 to 6.1 +/- 1.0 nmol.min-1.m-2; P = 0.01), suggesting suppression of SNS tone; 2) there was an augmented clonidine-mediated venoconstriction response [analysis of variance (ANOVA) P = 0.01]; and 3) there was no detectable change in phenylephrine-mediated venoconstriction (ANOVA P = 0.60). When compared with previous results from young subjects, maximal alpha 2-adrenergic venoconstriction during guanadrel was decreased in the elderly compared with the young, although their response appeared to be appropriately upregulated by the decrease in SNS tone. The lack of an age-related decrease in alpha 1-adrenergic venoconstriction, together with the lack of upregulation of this response during guanadrel, suggests that regulation of this alpha 1-adrenergic response is impaired in the older group.

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