Renal and cardiovascular effects of caffeine: A dose–response study

1987 ◽  
Vol 72 (6) ◽  
pp. 749-756 ◽  
Author(s):  
A. P. Passmore ◽  
G. B. Kondowe ◽  
G. D. Johnston
Keyword(s):  
Heart Rate ◽  
Diastolic Pressure ◽  
Renal Plasma Flow ◽  
Urine Volume ◽  
Systolic Pressure ◽  
Cardiovascular Effects ◽  
Plasma Renin ◽  
Urinary Sodium Excretion ◽  
Plasma Noradrenaline ◽  
Dose Response Study

1. The effects of increasing oral doses of caffeine (45, 90, 180 and 360 mg) on effective renal plasma flow (ERPF), plasma renin activity (PRA), serum electrolytes, plasma noradrenaline, blood pressure and heart rate were studied in eight healthy male volunteers. 2. Urine volume was increased by 360 mg of caffeine only. At caffeine doses greater than 90 mg urinary sodium excretion was significantly increased. There were no changes in ERPF. 3. Serum potassium was significantly reduced by 360 mg of caffeine. 4. Caffeine increased systolic pressure in a dose related manner. Diastolic pressure was also increased, but not in relation to dose. A 360 mg dose of caffeine produced a late increase in heart rate. These changes were not associated with any alterations in PRA or in plasma noradrenaline.

γ-l-Glutamyl-l-Dopa is a Dopamine Pro-Drug, Relatively Specific for the Kidney in Normal Subjects

1985 ◽  
Vol 69 (2) ◽  
pp. 207-214 ◽  
Author(s):  
D. P. Worth ◽  
J. N. Harvey ◽  
J. Brown ◽  
M. R. Lee
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Glomerular Filtration Rate ◽  
Plasma Renin Activity ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Urinary Sodium Excretion ◽  
Systemic Effects

1. γ-l-Glutamyl-l-dopa was given by intravenous infusion to eight normal subjects at doses of 12.5 and 100 μg min−1 kg−1. 2. Both doses of the dipeptide resulted in an increase in mean urinary sodium excretion. 3. Mean effective renal plasma flow rose at both doses, but mean glomerular filtration rate increased only at the lower dose. 4. There was a fall in mean plasma renin activity after the infusion of both 12.5 and 100 μg min−1kg−1. 5. Mean urine free dopamine excretion increased by 280- and 2500-fold at infusion rates of 12.5 and 100 μg min−1 kg−1 respectively. 6. Mean plasma free dopamine rose at both doses but the increase at 12.5 μg min−1 kg−1 was not to a level previously associated with systemic effects of the catecholamine. 7. On administration of the dipeptide at 12.5 μg min−1 kg−1 there were no changes in blood pressure or heart rate, but at the higher dose there was a fall in diastolic blood pressure. 8. At a dose of 12.5 μg min−1 kg−1 in man, there is kidney specific conversion of gludopa to dopamine.

Acute and chronic actions of bradykinin on renal function and arterial pressure

1985 ◽  
Vol 248 (1) ◽  
pp. F87-F92 ◽  
Author(s):  
J. P. Granger ◽  
J. E. Hall
Keyword(s):  
Arterial Pressure ◽  
Renal Plasma Flow ◽  
Urine Volume ◽  
Plasma Renin ◽  
Urinary Sodium Excretion ◽  
Renal Perfusion ◽  
Acute Effects ◽  
Plasma Aldosterone Concentration ◽  
Control Value ◽  
Renal Vascular

The present study was designed to examine the acute and chronic effects of increased levels of circulating bradykinin (BK) on control of renal hemodynamics, electrolyte excretion, and arterial pressure. Intrarenal infusion of BK (50 ng X kg-1 X min-1) for 60 min in five anesthetized dogs with renal perfusion pressure maintained at a constant level of 108 +/- 1 mmHg had no significant effect on glomerular filtration rate (GFR), whereas it increased renal blood flow (RBF) from a control value of 230 +/- 14 to 282 +/- 18, 266 +/- 15, and 253 +/- 17 ml/min after 15, 30, and 60 min of infusion, respectively. Acute intrarenal infusion of BK also increased urine volume (UV) from 0.255 +/- 0.044 to 0.523 +/- 0.103 ml/min and urinary sodium excretion (UNaV) from 5.72 +/- 1.5 to 13.7 +/- 3.4 mueq/min. To determine whether the potent acute effects of BK on RBF, UV, and UNaV lead to a chronic reduction in arterial pressure, BK (50 ng X kg-1 X min-1) was infused intrarenally for 7 days in conscious dogs. Intrarenal infusion of BK for 7 days had no significant effect on GFR, UNaV, UV, or arterial pressure. However, BK elevated renal plasma flow and decreased renal vascular resistance throughout the 7 days of infusion. Chronic intrarenal BK infusion caused no significant changes in plasma renin activity or plasma aldosterone concentration. Results from these studies indicate that although increased levels of bradykinin in the renal circulation can have potent acute effects on RBF, UV, and UNaV, these effects on UV and UNaV are not sustained and therefore do not result in long-term changes in arterial pressure.

Effects of Clonidine and Hydrochlorothiazide on the Cardiovascular Response to Mental Stress in Adolescent Hypertension

1982 ◽  
Vol 63 (s8) ◽  
pp. 455s-458s ◽  
Author(s):  
Bonita Falkner ◽  
Gaddo Onesti ◽  
Melton B. Affrime ◽  
David T. Lowenthal
Keyword(s):  
Heart Rate ◽  
Essential Hypertension ◽  
Mental Stress ◽  
Diastolic Pressure ◽  
Cardiovascular Response ◽  
Systolic Pressure ◽  
Cardiovascular Responses ◽  
Plasma Noradrenaline ◽  
Lower Plasma ◽  
Adrenergic Activity

1. The effects of clonidine and hydrochlorothiazide on the cardiovascular responses to mental stess were compared in 29 adolescents with essential hypertension. 2. Clonidine therapy was associated with lower diastolic pressures, heart rate and noradrenaline in response to mental stress. By contrast, hydrochlorothiazide resulted in the reduction of systolic pressure only. The mental stress testing produced a greater absolute diastolic pressure response and higher plasma noradrenaline on hydrochlorothiazide therapy. 3. Juveniles with essential hypertension may be more sensitive to central control of blood pressure and more resistant to diuretics. 4. The reduced diastolic pressure and heart rate response to central stimuli during clonidine therapy may be related to decreased adrenergic activity, as indicated by lower plasma noradrenaline.

Effect of alcohol withdrawal on blood pressure, plasma renin activity, aldosterone, cortisol and dopamine β-hydroxylase

1984 ◽  
Vol 66 (6) ◽  
pp. 659-663 ◽  
Author(s):  
L. T. Bannan ◽  
J. F. Potter ◽  
D. G. Beevers ◽  
J. B. Saunders ◽  
J. R. F. Walters ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Alcohol Withdrawal ◽  
Diastolic Pressure ◽  
Urine Volume ◽  
Plasma Renin ◽  
Renin Activity ◽  
Withdrawal Symptoms ◽  
Urinary Volume ◽  
Blood Pressures

1. Sixty-five alcoholic patients admitted for detoxification had blood pressure, withdrawal symptoms, plasma cortisol (PC) and plasma aldosteron (PA) levels, plasma renin activity (PRA), and serum dopamin β-hydroxylase (DBH) levels measured on the first and fourth days after admission. 2. On the morning after admission blood pressure was elevated (>140/90) in 32 patients (49%) and was 160/95mmHg or more in 21 (32%). PRA was initially elevated in 41 patients, PA levels in 14, and 13 patients had raised PC levels. By the fourth day, blood pressure and bio-chemical measures had fallen significantly while urine volume and sodium output, low on admission, had increased significantly. On admission urinary metanephrine levels were raised in four out of the 31 patients who had them measured. 3. The height of both the systolic and diastolic blood pressures was significantly related to the severity of the alcohol. withdrawal symptoms. Of the biochemical parameters measured, PC level correlated with systolic but not diastolic pressure, and urinary volume was inversely correlated with the height of the diastolic pressure. No relationship was found between blood pressure and PRA or PA level. 4. The pressor effect of alcohol withdrawal could be due to sympathetic nervous system overactivity, or possibly to hypercortisolaemia. The first hypothesis seems more likely.

Are Racial Differences in Essential Hypertension Due to Different Pathogenetic Mechanisms?

1978 ◽  
Vol 55 (s4) ◽  
pp. 383s-386s ◽  
Author(s):  
P. S. Sever ◽  
W. S. Peart ◽  
T. W. Meade ◽  
I. B. Davies ◽  
D. Gordon ◽  
...  
Keyword(s):  
Essential Hypertension ◽  
Plasma Renin Activity ◽  
Racial Differences ◽  
Plasma Renin ◽  
Urinary Sodium Excretion ◽  
Renin Activity ◽  
Plasma Noradrenaline ◽  
Noradrenaline Concentration ◽  
Blacks And Whites ◽  
Made In

1. Plasma noradrenaline concentration and plasma renin activity were measured in a control, British, urban population (n = 115) in which blacks were matched for age and sex with whites. 2. Similar measurements were made in subjects with essential hypertension (77 white and 23 black), and 48 healthy normotensive white civil servants. 3. In controls blood pressure was significantly higher in blacks; it correlated with age in both races and with pulse rate in blacks. There were no significant racial differences in plasma noradrenaline which was positively correlated with age in both blacks and whites. Mean plasma renin activity was 55% lower in blacks, and this difference was not related to urinary sodium excretion. 4. In hypertensive subjects plasma noradrenaline positively correlated with age in blacks. This relationship was not found in whites in whom 20% of young hypertensive subjects (<45 years) had significantly raised plasma noradrenaline. Plasma renin activity was again significantly lower in blacks. In white hypertensives plasma noradrenaline and renin activity were significantly correlated. 5. There may be racial differences in the pathogenesis of essential hypertension.

Control circulatory values of morphinepentobarbitalized dogs

1960 ◽  
Vol 199 (5) ◽  
pp. 797-799 ◽  
Author(s):  
S. Deavers ◽  
E. L. Smith ◽  
R. A. Huggins
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Cell Volume ◽  
Blood Volume ◽  
Plasma Volume ◽  
Protein Concentration ◽  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Control Data ◽  
Plasma Protein Concentration

Mean control data on a series of 100 dogs are presented. Cell volume, measured with Cr51-tagged red cells and plasma volume determined simultaneously by T-1824 dye was 33.5 ± 0.74 cc/kg and 50.2 ± 1.11 cc/kg, respectively. The venous hematocrit was 45.2% and the circulatory/venous hematocrit ratio was 0.89 ± 0.01 for the group. The plasma protein concentration of these animals was 6.25 ± 0.07 gm/100 cc. No difference in blood volume per unit of body weight was found between large (12.6 kg) and small (5.8 kg) dogs. The femoral mean systolic pressure was 139.0 ± 2.53 mm Hg, the diastolic pressure 65.6 ± 1.46 mm Hg and the heart rate 85.9 ± 2.86/min.

Alcohol: Effect on Blood Pressure and Predisposition to Hypertension

1981 ◽  
Vol 61 (s7) ◽  
pp. 373s-375s ◽  
Author(s):  
P. D. Arkwright ◽  
L. J. Beilin ◽  
I. Rouse ◽  
B. K. Armstrong ◽  
R. Vandongen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Essential Hypertension ◽  
Alcohol Consumption ◽  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Threshold Effect ◽  
Health Questionnaire ◽  
Government Employees ◽  
Weekly Alcohol Consumption

1. The association between alcohol consumption and blood pressure was studied in 491 Government employees. The men, aged 21–45 years, volunteered to complete a health questionnaire and submitted to standardized measurements of blood pressure, heart rate and body size. 2. Average weekly alcohol consumption correlated with systolic pressure (r = 0.18, P &lt; 0.001) but not with diastolic pressure. Systolic pressure increased progressively with increasing alcohol consumption with no obvious threshold effect. The effect of alcohol was independent of age, obesity (Quetelet's index) or cigarette smoking. 3. Results indicate that alcohol ranks close to obesity as a preventable cause of essential hypertension in the community.

scholarly journals Effects of Imagery as Visual Stimuli on the Physiological and Emotional Responses

J ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 206-225 ◽  
Author(s):  
Nadeesha Gunaratne ◽  
Claudia Viejo ◽  
Thejani Gunaratne ◽  
Damir Torrico ◽  
Hollis Ashman ◽  
...  
Keyword(s):  
Heart Rate ◽  
Diastolic Pressure ◽  
Visual Stimuli ◽  
Systolic Pressure ◽  
Emotional Responses ◽  
Accurate Information ◽  
Dimensional Model ◽  
Picture Database ◽  
Face Scale ◽  
General Linear Regression Model

Study of emotions has gained interest in the field of sensory and consumer research. Accurate information can be obtained by studying physiological behavior along with self-reported-responses. The aim was to identify physiological and self-reported-responses towards visual stimuli and predict self-reported-responses using biometrics. Panelists (N = 63) were exposed to 12 images (ten from Geneva Affective PicturE Database (GAPED), two based on common fears) and a questionnaire (Face scale and EsSense). Emotions from facial expressions (FaceReaderTM), heart rate (HR), systolic pressure (SP), diastolic pressure (DP), and skin temperature (ST) were analyzed. Multiple regression analysis was used to predict self-reported-responses based on biometrics. Results showed that physiological along with self-reported responses were able to separate images based on cluster analysis as positive, neutral, or negative according to GAPED classification. Emotional terms with high or low valence were predicted by a general linear regression model using biometrics, while calm, which is in the center of emotion dimensional model, was not predicted. After separating images, positive and neutral categories could predict all emotional terms, while negative predicted Happy, Sad, and Scared. Heart Rate predicted emotions in positive (R2 = 0.52 for Scared) and neutral (R2 = 0.55 for Sad) categories while ST in positive images (R2 = 0.55 for Sad, R2 = 0.45 for Calm).

Cardiac Baroreflex during the Postoperative Period in Patients with Hypertension 

1999 ◽  
Vol 90 (3) ◽  
pp. 681-692 ◽  
Author(s):  
Joel L. Parlow ◽  
Gerard Begou ◽  
Pierre Sagnard ◽  
Jean Marie Cottet-Emard ◽  
Jean Claude Levron ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Essential Hypertension ◽  
Rate Control ◽  
Diastolic Pressure ◽  
Elective Surgery ◽  
Recovery Period ◽  
Systolic Pressure ◽  
Heart Rate Control ◽  
Baroreflex Control

Background Patients with essential hypertension show altered baroreflex control of heart rate, and during the perioperative period they demonstrate increased circulatory instability. Clonidine has been shown to reduce perioperative circulatory instability. This study documents changes in measures of heart rate control after surgery in patients with essential hypertension and determines the effects of clonidine on postoperative heart rate control in these patients. Methods Using a randomized double-blind placebo-controlled design, 20 patients with essential hypertension (systolic pressure &gt;160 mm Hg or diastolic pressure &gt;95 mm Hg for &gt; or =1 yr) were assigned to receive clonidine (or placebo), 6 microg/kg orally 120 min before anesthesia and 3 microg/kg intravenously over 60 min before the end of surgery. The spontaneous baroreflex ("sequence") technique and analysis of heart rate variability were used to quantify control of heart rate at baseline, before induction of anesthesia, and 1 and 3 h postoperatively. Results Baroreflex slope and heart rate variability were reduced postoperatively in patients given placebo but not those given clonidine. Clonidine resulted in greater postoperative baroreflex slope and power at all frequency ranges compared with placebo (4.9+/-2.9 vs. 2.2+/-2.1 ms/mm Hg for baroreflex slope, 354+/-685 vs. 30+/-37 ms2/Hz for high frequency variability). Clonidine also resulted in lower concentrations of catecholamine, decreased mean heart rate and blood pressure, and decreased perioperative tachycardia and hypertension. Conclusions Patients with hypertension exhibit reduced heart rate control during the recovery period after elective surgery. Clonidine prevents this reduction in heart rate control. This may represent a basis for the improved circulatory stability seen with perioperative administration of clonidine.

The Effects of Cardioselective and Non-Selective β-Adrenoceptor Blockade on the Hypokalaemic and Cardiovascular Responses to Adrenomedullary Hormones in Man

1983 ◽  
Vol 65 (2) ◽  
pp. 143-147 ◽  
Author(s):  
A. D. Struthers ◽  
J. L. Reid ◽  
R. Whitesmith ◽  
J. C. Rodger
Keyword(s):  
Heart Rate ◽  
Serum Potassium ◽  
Qt Interval ◽  
Diastolic Pressure ◽  
Plasma Concentrations ◽  
Systolic Pressure ◽  
Cardiovascular Responses ◽  
Potassium Influx ◽  
Adrenomedullary Hormones ◽  
Stimulation Of

1. Adrenaline was infused intravenously in nine normal volunteers to plasma concentrations similar to those found after myocardial infarction. This study was undertaken on three occasions after 5 days' treatment with placebo or the β-adrenoceptor antagonists, atenolol or timolol. 2. Adrenaline increased the systolic pressure by 11 mmHg, decreased the diastolic pressure by 14 mmHg, and increased the heart rate by 7 beats/min. These changes were prevented by atenolol. However, after timolol the diastolic pressure rose (+19 mmHg) and heart rate fell (− 8 beats/min). 3. Adrenaline caused the corrected QT interval (QTc) to lengthen (0.36 ± 0.02 s to 0.41 ± 0.06 s). No significant changes were found in the QTc when subjects were pretreated with atenolol or timolol. 4. The serum potassium fell from 4.06 to 3.22 mmol/l after adrenaline. Serum potassium fell to a lesser extent to 3.67 mmol/l after atenolol and actually increased to 4.25 mmol/l after timolol. Adrenaline-mediated hypokalaemia appears to result from the stimulation of a β2-adrenoceptor linked to membrane Na+/K+-ATPase causing potassium influx.

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