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1.
Braz. j. med. biol. res ; 42(4): 386-396, Apr. 2009. graf, tab
Article in English | LILACS | ID: lil-509171

ABSTRACT

The autonomic nervous system plays an important role in physiological and pathological conditions, and has been extensively evaluated by parametric and non-parametric spectral analysis. To compare the results obtained with fast Fourier transform (FFT) and the autoregressive (AR) method, we performed a comprehensive comparative study using data from humans and rats during pharmacological blockade (in rats), a postural test (in humans), and in the hypertensive state (in both humans and rats). Although postural hypotension in humans induced an increase in normalized low-frequency (LFnu) of systolic blood pressure, the increase in the ratio was detected only by AR. In rats, AR and FFT analysis did not agree for LFnu and high frequency (HFnu) under basal conditions and after vagal blockade. The increase in the LF/HF ratio of the pulse interval, induced by methylatropine, was detected only by FFT. In hypertensive patients, changes in LF and HF for systolic blood pressure were observed only by AR; FFT was able to detect the reduction in both blood pressure variance and total power. In hypertensive rats, AR presented different values of variance and total power for systolic blood pressure. Moreover, AR and FFT presented discordant results for LF, LFnu, HF, LF/HF ratio, and total power for pulse interval. We provide evidence for disagreement in 23 percent of the indices of blood pressure and heart rate variability in humans and 67 percent discordance in rats when these variables are evaluated by AR and FFT under physiological and pathological conditions. The overall disagreement between AR and FFT in this study was 43 percent.


Subject(s)
Animals , Female , Humans , Male , Middle Aged , Rats , Young Adult , Autonomic Nervous System/physiopathology , Fourier Analysis , Heart Block/physiopathology , Hypertension/physiopathology , Atropine Derivatives/pharmacology , Heart Block/chemically induced , Heart Rate/physiology , Rats, Inbred SHR , Rats, Wistar , Severity of Illness Index , Tilt-Table Test , Young Adult
2.
Braz J Med Biol Res ; 42(4): 386-96, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19330268

ABSTRACT

The autonomic nervous system plays an important role in physiological and pathological conditions, and has been extensively evaluated by parametric and non-parametric spectral analysis. To compare the results obtained with fast Fourier transform (FFT) and the autoregressive (AR) method, we performed a comprehensive comparative study using data from humans and rats during pharmacological blockade (in rats), a postural test (in humans), and in the hypertensive state (in both humans and rats). Although postural hypotension in humans induced an increase in normalized low-frequency (LFnu) of systolic blood pressure, the increase in the ratio was detected only by AR. In rats, AR and FFT analysis did not agree for LFnu and high frequency (HFnu) under basal conditions and after vagal blockade. The increase in the LF/HF ratio of the pulse interval, induced by methylatropine, was detected only by FFT. In hypertensive patients, changes in LF and HF for systolic blood pressure were observed only by AR; FFT was able to detect the reduction in both blood pressure variance and total power. In hypertensive rats, AR presented different values of variance and total power for systolic blood pressure. Moreover, AR and FFT presented discordant results for LF, LFnu, HF, LF/HF ratio, and total power for pulse interval. We provide evidence for disagreement in 23% of the indices of blood pressure and heart rate variability in humans and 67% discordance in rats when these variables are evaluated by AR and FFT under physiological and pathological conditions. The overall disagreement between AR and FFT in this study was 43%.


Subject(s)
Autonomic Nervous System/physiopathology , Fourier Analysis , Heart Block/physiopathology , Hypertension/physiopathology , Animals , Atropine Derivatives/pharmacology , Female , Heart Block/chemically induced , Heart Rate/physiology , Humans , Male , Middle Aged , Rats , Rats, Inbred SHR , Rats, Wistar , Severity of Illness Index , Tilt-Table Test , Young Adult
3.
Braz J Med Biol Res ; 41(10): 849-53, 2008 Oct.
Article in English | MEDLINE | ID: mdl-19037531

ABSTRACT

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 +/- 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 +/- 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 +/- 10/81 +/- 5 mmHg) compared with ONT (99 +/- 13/67 +/- 5 mmHg). The increase in blood pressure was greater in OMH (Delta SBP = 17 +/- 2 vs Delta SBP = 9 +/- 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (Delta HR = 13 +/- 2 vs Delta HR = 20 +/- 3 bpm in ONT) during isometric exercise(handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 +/- 6 vs 11 +/- 4 burst/min in ONT) and exhibited a greater increase (Delta = 18 +/- 10 vs Delta = 8 +/- 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT.


Subject(s)
Exercise/physiology , Hypertension, Malignant/physiopathology , Stress, Physiological/physiology , Sympathetic Nervous System/physiopathology , Adult , Case-Control Studies , Female , Heart Rate/physiology , Humans , Hypertension, Malignant/blood , Hypertension, Malignant/genetics , Male , Parents
4.
Braz. j. med. biol. res ; 41(10): 849-853, Oct. 2008. graf, tab
Article in English | LILACS | ID: lil-496801

ABSTRACT

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 ± 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 ± 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 ± 10/81 ± 5 mmHg) compared with ONT (99 ± 13/67 ± 5 mmHg). The increase in blood pressure was greater in OMH (Ä SBP = 17 ± 2 vs Ä SBP = 9 ± 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (Ä HR = 13 ± 2 vs Ä HR = 20 ± 3 bpm in ONT) during isometric exercise (handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 ± 6 vs 11 ± 4 burst/min in ONT) and exhibited a greater increase (Ä = 18 ± 10 vs Ä = 8 ± 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT.


Subject(s)
Adult , Female , Humans , Male , Exercise/physiology , Hypertension, Malignant/physiopathology , Stress, Physiological/physiology , Sympathetic Nervous System/physiopathology , Case-Control Studies , Heart Rate/physiology , Hypertension, Malignant/blood , Hypertension, Malignant/genetics , Parents
5.
Auton Neurosci ; 133(2): 128-35, 2007 May 30.
Article in English | MEDLINE | ID: mdl-17188942

ABSTRACT

The time-course of changes in renal sympathetic nerve activity (RSNA), arterial and cardiopulmonary baroreflexes sensitivities was evaluated in conscious rats eight hours (8 h) and ten days (10 day) after myocardial infarction (MI), induced by coronary artery ligation. RSNA was recorded by a platinum electrode implanted in left renal nerve. Arterial and cardiopulmonary baroreflexes sensitivities were evaluated by changes in blood pressure and serotonin administration, respectively. Both 8 h and 10 day groups presented hypotension (103+/-4 vs. 102+/-2 vs. 115+/-4 mm Hg), but only 8 h showed tachycardia (422+/-22 vs. 378+/-11 vs. 384+/-9 bpm) when compared to Control rats. RSNA was depressed 8 h after MI and increased in 10 day group (12+/-2 vs. 39+/-8 vs. 22+/-2 mV/cycle). Although arterial baroreflex control of heart rate was similar in all groups, the arterial baroreflex control of RSNA in 8 h group was impaired during reductions (-0.35+/-0.10 vs. -1.66+/-0.23 vs. -0.09+/-0.14 mV/cycle/mm Hg) or increases (-0.77+/-0.17 vs. -1.63+/-0.58 vs. -1.66+/-0.17 mV/cycle/mm Hg) in blood pressure when compared to Control animals. Moreover, cardiopulmonary baroreflex bradycardic response was increased in 8 h rats and normalized in 10 day group. The results suggest that the increased cardiopulmonary baroreflex sensitivity in 8 h may contribute to the reduction in the tonic level of RSNA as well as in the impairment of the baroreflex control of RSNA in the presence of hypotension.


Subject(s)
Baroreflex/physiology , Myocardial Infarction/physiopathology , Renal Artery/innervation , Sympathetic Fibers, Postganglionic/physiopathology , Animals , Blood Pressure/drug effects , Blood Pressure/physiology , Heart Rate/physiology , Hypotension/physiopathology , Male , Rats , Rats, Wistar , Renin/blood , Serotonin/metabolism , Serotonin/pharmacology , Tachycardia/physiopathology
6.
Braz J Med Biol Res ; 37(11): 1615-22, 2004 Nov.
Article in English | MEDLINE | ID: mdl-15517075

ABSTRACT

The first minutes of the time course of cardiopulmonary reflex control evoked by lower body negative pressure (LBNP) in patients with hypertensive cardiomyopathy have not been investigated in detail. We studied 15 hypertensive patients with left ventricular dysfunction (LVD) and 15 matched normal controls to observe the time course response of the forearm vascular resistance (FVR) during 3 min of LBNP at -10, -15, and -40 mmHg in unloading the cardiopulmonary receptors. Analysis of the average of 3-min intervals of FVR showed a blunted response of the LVD patients at -10 mmHg (P = 0.03), but a similar response in both groups at -15 and -40 mmHg. However, using a minute-to-minute analysis of the FVR at -15 and -40 mmHg, we observed a similar response in both groups at the 1st min, but a marked decrease of FVR in the LVD group at the 3rd min of LBNP at -15 mmHg (P = 0.017), and -40 mmHg (P = 0.004). Plasma norepinephrine levels were analyzed as another neurohumoral measurement of cardiopulmonary receptor response to LBNP, and showed a blunted response in the LVD group at -10 (P = 0.013), -15 (P = 0.032) and -40 mmHg (P = 0.004). We concluded that the cardiopulmonary reflex response in patients with hypertensive cardiomyopathy is blunted at lower levels of LBNP. However, at higher levels, the cardiopulmonary reflex has a normal initial response that decreases progressively with time. As a consequence of the time-dependent response, the cardiopulmonary reflex response should be measured over small intervals of time in clinical studies.


Subject(s)
Baroreflex , Hypertension/physiopathology , Pressoreceptors/physiopathology , Vascular Resistance , Ventricular Dysfunction, Left/physiopathology , Adult , Case-Control Studies , Female , Forearm/blood supply , Hemodynamics , Humans , Hypertension/blood , Lower Body Negative Pressure , Male , Middle Aged , Norepinephrine/blood , Time Factors , Ventricular Dysfunction, Left/blood
7.
Braz. j. med. biol. res ; 37(11): 1615-1622, Nov. 2004. tab, graf
Article in English | LILACS | ID: lil-385874

ABSTRACT

The first minutes of the time course of cardiopulmonary reflex control evoked by lower body negative pressure (LBNP) in patients with hypertensive cardiomyopathy have not been investigated in detail. We studied 15 hypertensive patients with left ventricular dysfunction (LVD) and 15 matched normal controls to observe the time course response of the forearm vascular resistance (FVR) during 3 min of LBNP at -10, -15, and -40 mmHg in unloading the cardiopulmonary receptors. Analysis of the average of 3-min intervals of FVR showed a blunted response of the LVD patients at -10 mmHg (P = 0.03), but a similar response in both groups at -15 and -40 mmHg. However, using a minute-to-minute analysis of the FVR at -15 and -40 mmHg, we observed a similar response in both groups at the 1st min, but a marked decrease of FVR in the LVD group at the 3rd min of LBNP at -15 mmHg (P = 0.017), and -40 mmHg (P = 0.004). Plasma norepinephrine levels were analyzed as another neurohumoral measurement of cardiopulmonary receptor response to LBNP, and showed a blunted response in the LVD group at -10 (P = 0.013), -15 (P = 0.032) and -40 mmHg (P = 0.004). We concluded that the cardiopulmonary reflex response in patients with hypertensive cardiomyopathy is blunted at lower levels of LBNP. However, at higher levels, the cardiopulmonary reflex has a normal initial response that decreases progressively with time. As a consequence of the time-dependent response, the cardiopulmonary reflex response should be measured over small intervals of time in clinical studies.


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Baroreflex , Hypertension/physiopathology , Pressoreceptors/physiopathology , Vascular Resistance , Ventricular Dysfunction, Left/physiopathology , Case-Control Studies , Forearm/blood supply , Hemodynamics , Hypertension/blood , Lower Body Negative Pressure , Norepinephrine/blood , Time Factors , Ventricular Dysfunction, Left/blood
8.
Circulation ; 104(15): 1792-8, 2001 Oct 09.
Article in English | MEDLINE | ID: mdl-11591616

ABSTRACT

BACKGROUND: The peripheral and central chemoreflexes are important autonomic mechanisms for regulating breathing and cardiovascular function. Although pathological inflammatory infiltration of the peripheral chemoreceptors and central nervous system has been reported in Chagas' disease, functional evaluation of chemoreflexes has not yet been performed. METHODS AND RESULTS: The hypothesis that chemoreflex function is altered in patients with Chagas' heart disease (CH) but normal left ventricle function was tested in 12 CH patients and 13 matched control subjects. The ventilatory rate, minute ventilation, heart rate, mean arterial pressure, forearm blood flow, forearm vascular resistance, and venous norepi-nephrine responses to hypoxia and hypercapnia were determined. During hypoxia, the decrease in oxygen saturation was smaller in CH patients, despite a similar ventilatory response between groups. Both groups showed an increase in heart rate during hypoxia, but this response was blunted in CH patients. Although the mean arterial pressure response to hypoxia was similar in both groups, forearm vascular resistance significantly decreased in control subjects while remaining unchanged in CH patients. Moreover, a significant increase in plasma norepinephrine levels elicited by stimulation of peripheral chemoreceptors was observed only in the CH group. During hypercapnia, the increase in minute ventilation was smaller in CH patients, who did not exhibit the increase in norepinephrine observed in control subjects. CONCLUSIONS: These data suggest that CH potentiates respiratory, cardiovascular, and autonomic responses to peripheral chemoreceptor activation by hypoxia in patients with normal left ventricular function. The ventilatory and sympathetic responses to central chemoreceptor activation by hypercapnia, however, are significantly blunted.


Subject(s)
Autonomic Nervous System Diseases/physiopathology , Chagas Cardiomyopathy/physiopathology , Chemoreceptor Cells/physiopathology , Peripheral Nervous System Diseases/physiopathology , Reflex, Abnormal , Adult , Autonomic Nervous System Diseases/complications , Autonomic Nervous System Diseases/diagnosis , Blood Flow Velocity , Blood Pressure , Capnography , Chagas Cardiomyopathy/complications , Female , Forearm/blood supply , Forearm/physiopathology , Heart Rate , Humans , Hypercapnia/physiopathology , Hyperoxia , Hypoxia/physiopathology , Male , Middle Aged , Norepinephrine/blood , Oximetry , Peripheral Nervous System Diseases/complications , Peripheral Nervous System Diseases/diagnosis , Pulmonary Ventilation , Vascular Resistance , Ventricular Function, Left
9.
Arq Bras Cardiol ; 75(3): 235-42, 2000 Sep.
Article in English, Portuguese | MEDLINE | ID: mdl-11018809

ABSTRACT

We report the case of a 72-year-old female with pure autonomic failure, a rare entity, whose diagnosis of autonomic dysfunction was determined with a series of complementary tests. For approximately 2 years, the patient has been experiencing dizziness and a tendency to fall, a significant weight loss, generalized weakness, dysphagia, intestinal constipation, blurred vision, dry mouth, and changes in her voice. She underwent clinical assessment and laboratory tests (biochemical tests, chest X-ray, digestive endoscopy, colonoscopy, chest computed tomography, abdomen and pelvis computed tomography, abdominal ultrasound, and ambulatory blood pressure monitoring). Measurements of catecholamine and plasmatic renin activity were performed at rest and after physical exercise. Finally the patient underwent physiological and pharmacological autonomic tests that better diagnosed dysautonomia.


Subject(s)
Autonomic Nervous System Diseases/physiopathology , Aged , Autonomic Nervous System Diseases/complications , Baroreflex/physiology , Bradycardia/physiopathology , Dizziness/etiology , Female , Heart Function Tests , Heart Rate/drug effects , Humans , Hypotension, Orthostatic/physiopathology , Reflex, Abnormal/physiology , Tachycardia/physiopathology , Tilt-Table Test
10.
Hypertension ; 36(6): 1035-9, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11116121

ABSTRACT

No study has been performed on reflexes originating from receptors in the heart that might be involved in the pathological lesions of Chagas' heart disease. Our study was undertaken to analyze the role of cardiopulmonary reflex on cardiovascular control in Chagas' disease. We studied 14 patients with Chagas' disease without heart failure and 12 healthy matched volunteers. Central venous pressure, arterial blood pressure, heart rate, forearm blood flow, and forearm vascular resistance were recorded during deactivation of cardiopulmonary receptors. By reducing central venous pressure by applying -10 and -15 mm Hg of negative pressure to the lower body, we observed (a) a similar decrease of central venous pressure in both groups; (b) a marked increase in forearm vascular resistance in the control group but a blunted increase in the Chagas' group; and (c) no significant changes in blood pressure and heart rate. To analyze cardiopulmonary and arterial receptors, we applied -40 mm Hg of lower-body negative pressure. As a consequence, (a) central venous pressure decreased similarly in both groups; (b) blood pressure was maintained in the control group, whereas in patients with Chagas' disease, a decrease in systolic and mean arterial pressure occurred; (c) heart rate increased in both groups; and (d) forearm vascular resistance increased significantly and similarly in both groups. Unloading of receptors with low levels of lower-body negative pressure did not increase forearm vascular resistance in patients with Chagas' disease, which suggests that the reflex mediated by cardiopulmonary receptors is impaired in patients with Chagas' disease without heart failure. Overall control of circulation appears to be compromised because patients did not maintain blood pressure under high levels of lower-body negative pressure.


Subject(s)
Baroreflex , Chagas Cardiomyopathy/physiopathology , Adult , Analysis of Variance , Autonomic Nervous System/physiopathology , Blood Pressure , Female , Heart Rate , Humans , Male , Pressoreceptors/physiology , Regional Blood Flow/physiology
11.
Braz J Med Biol Res ; 33(1): 51-4, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10625874

ABSTRACT

Although a slightly elevated office blood pressure (BP) has been reported in several studies, little is known about the prolonged resting blood pressure, heart rate (HR) and baroreflex sensitivity (BRS) of prehypertensive subjects with a family history of hypertension. Office blood pressure, prolonged resting (1 h) BP and HR were measured in 25 young normotensives with a positive family history of hypertension (FH+) and 25 young normotensives with a negative family history of hypertension (FH-), matched for age, sex, and body mass index. After BP and HR measurements, blood samples were collected for the determination of norepinephrine, plasma renin activity and aldosterone levels, and baroreflex sensitivity was then tested. Casual BP, prolonged resting BP and heart rate were significantly higher in the FH+ group (119.9 +/- 11.7/78.5 +/- 8.6 mmHg, 137.3 +/- 12.3/74.4 +/- 7.9 mmHg, 68.5 +/- 8.4 bpm) compared to the FH- group (112.9 +/- 11.4/71.2 +/- 8.3 mmHg, 128.0 +/- 11. 8/66.5 +/- 7.4 mmHg, 62.1 +/- 6.0 bpm). Plasma norepinephrine level was significantly higher in the FH+ group (220.1 +/- 104.5 pg/ml) than in the FH- group (169.1 +/- 63.3 pg/ml). Baroreflex sensitivity to tachycardia (0.7 +/- 0.3 vs 1.0 +/- 0.5 bpm/mmHg) was depressed in the FH+ group (P<0.05). The FH+ group exhibited higher casual blood pressure, prolonged resting blood pressure, heart rate and plasma norepinephrine levels than the FH- group (P<0.05), suggesting an increased sympathetic tone in these subjects. The reflex tachycardia was depressed in the FH+ group.


Subject(s)
Blood Pressure/physiology , Heart Rate/physiology , Hypertension/genetics , Adolescent , Adult , Aldosterone/blood , Baroreflex , Body Mass Index , Chi-Square Distribution , Female , Humans , Hypertension/physiopathology , Male , Membrane Potentials , Norepinephrine/blood , Renin/blood , Sensitivity and Specificity , Sympathetic Nervous System/physiopathology
12.
Braz. j. med. biol. res ; 33(1): 51-4, Jan. 2000. tab
Article in English | LILACS | ID: lil-252256

ABSTRACT

Although a slightly elevated office blood pressure (BP) has been reported in several studies, little is known about the prolonged resting blood pressure, heart rate (HR) and baroreflex sensitivity (BRS) of prehypertensive subjects with a family history of hypertension. Office blood pressure, prolonged resting (1 h) BP and HR were measured in 25 young normotensives with a positive family history of hypertension (FH+) and 25 young normotensives with a negative family history of hypertension (FH-), matched for age, sex, and body mass index. After BP and HR measurements, blood samples were collected for the determination of norepinephrine, plasma renin activity and aldosterone levels, and baroreflex sensitivity was then tested. Casual BP, prolonged resting BP and heart rate were significantly higher in the FH+ group (119.9 + or - 11.7/78.5 + or - 8.6 mmHg, 137.3 + or - 12.3/74.4 + or - 7.9 mmHg, 68.5 + or - 8.4 bpm) compared to the FH- group (112.9 + or - 11.4/71.2 + or - 8.3 mmHg, 128.0 + or - 11.8/66.5 + or - 7.4 mmHg, 62.1 + or - 6.0 bpm). Plasma norepinephrine level was significantly higher in the FH+ group (220.1 + or - 104.5 pg/ml) than in the FH- group (169.1 + or - 63.3 pg/ml). Baroreflex sensitivity to tachycardia (0.7 + or - 0.3 vs 1.0 + or - 0.5 bpm/mmHg) was depressed in the FH+ group (P<0.05). The FH+ group exhibited higher casual blood pressure, prolonged resting blood pressure, heart rate and plasma norepinephrine levels than the FH- group (P<0.05), suggesting an increased sympathetic tone in these subjects. The reflex tachycardia was depressed in the FH+ group


Subject(s)
Female , Humans , Adult , Adolescent , Baroreflex , Blood Pressure/physiology , Heart Rate/physiology , Hypertension/genetics , Norepinephrine/blood , Sympathetic Nervous System/physiopathology , Aldosterone/blood , Body Mass Index , Chi-Square Distribution , Hypertension/diagnosis , Hypertension/physiopathology , Membrane Potentials , Renin/blood , Sensitivity and Specificity
13.
Hypertension ; 30(3 Pt 2): 629-31, 1997 Sep.
Article in English | MEDLINE | ID: mdl-9322993

ABSTRACT

Metabolic abnormalities are usually reported in hypertensive patients. These metabolic alterations seem to begin in childhood. The young offspring of hypertensive parents have not been studied thoroughly for metabolic alterations. The aim of this study was to examine the level of total cholesterol, LDL cholesterol, VLDL cholesterol, HDL cholesterol, uric acid, glycemia, aldosterone, and plasma renin activity in a population of 42 young, slender normotensive subjects with positive family history of hypertension (FH+) or negative family history of hypertension (FH-). Measurements were made in 20 young normotensive subjects (age 21.1+/-2.2 years, 11 males, 15 white, 5 oriental, body mass index of 22.1+/-2.3 kg/m2) with FH+ and 22 young normotensive subjects (age 19.9+/-1.4 years, 17 males, 17 white, 5 oriental, body mass index of 22.1+/-2.3 kg/m2) with FH-. The total cholesterol (4.47+/-0.8 versus 3.95+/-0.6 mmol/L), LDL cholesterol (2.74+/-0.63 versus 2.36+/-0.61 mmol/L), VLDL cholesterol (0.5+/-0.25 versus 0.35+/-0.09 mmol/L), and triglycerides (2.52+/-1.26 versus 1.76+/-0.5 mmol/L) were significantly elevated (P<.05) in the FH+ group compared with the FH- group. The total cholesterol/HDL cholesterol ratio was significantly higher in the group with a positive family history of hypertension (3.75+/-0.02 versus 3.11+/-0.02, P<.05). Glycemia was slightly elevated in the FH+ group (2.16+/-0.29 mmol/L) but was not significantly different from that of the FH- group (2+/-0.2 mmol/L). Uric acid, plasma renin activity, and aldosterone were similar in both groups. We conclude that young, slender normotensive subjects with a positive history of hypertension show alterations in lipid metabolism, suggesting a positive correlation between lipid metabolism and hypertension heredity.


Subject(s)
Hypertension/genetics , Lipid Metabolism , Adult , Cholesterol/blood , Female , Humans , Hypertension/metabolism , Male
14.
Am J Physiol ; 271(1 Pt 2): R34-41, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8760201

ABSTRACT

Angiotensin II (ANG II) and arginine vasopressin (AVP) act on area postrema (AP) neurons to modulate the baroreflex. Because activation of AP neurons by either ANG II or AVP increases intracellular free Ca2+ concentrations ([Ca2+]i), the goal of this study was to analyze the factors affecting the [Ca2+]i responses to ANG II and AVP. Neurons were recovered from 14- to 16-day old rats and studied after 8-14 days in culture by use of the microscopic digital image analysis for fura 2-loaded cells. The effects of ANG II (100 nM) and AVP (100 nM) on [Ca2+]i were determined in normal (2 mM) and low (< 10 nM) extracellular Ca2+ concentrations. In 143 of 240 neurons, ANG II increased [Ca2+]i 4.65-fold after 20 s, and a similar response was observed in the absence of extracellular Ca2+ (3.65-fold after 20 s). After 60 s of observation, steady-state levels of increased [Ca2+]i were still present under both conditions. Pretreatment with AT1 antagonist or pertussis toxin abolished the response to ANG II. AVP also increased [Ca2+]i (3.6-fold at peak, 20 s) in normal and low extracellular Ca2+. Pretreatment with AVP V1 antagonist or pertussis toxin abolished the response to AVP. This study indicates that ANG II-induced increases in [Ca2+]i are independent of extracellular Ca2+ concentrations and involve the activation of AT1 receptors and a pertussis toxin-sensitive G protein. Although AVP affects a fewer number of AP neurons, the mechanisms of activation are also independent of extracellular Ca2+ concentration and are mediated by a pertussis toxin-sensitive G protein.


Subject(s)
Angiotensin II/pharmacology , Arginine Vasopressin/pharmacology , Neurons/drug effects , Rhombencephalon/drug effects , Animals , Calcium/metabolism , Calcium/physiology , Cerebral Ventricles , Cytosol/metabolism , Enzyme Activation , Extracellular Space/metabolism , GTP-Binding Proteins/physiology , Guanosine Triphosphate/physiology , Inositol Phosphates/physiology , Neurons/physiology , Osmolar Concentration , Protein Kinases/metabolism , Rats , Rhombencephalon/cytology , Rhombencephalon/physiology
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