9 results on '"Physiology"'
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2. Angiotensin II responses in AT1A receptor-deficient mice: A role for AT1B receptors in blood...
- Author
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Oliverio, Michael I. and Best, Christopher F.
- Subjects
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BAROREFLEXES , *RENIN , *ANGIOTENSINS , *BLOOD pressure , *PHYSIOLOGY - Abstract
Demonstrates the in vivo pressor effects mediated by renin-angiotensin system type 1B (AT1B) receptors and that when AT1A receptors are absent, the AT1B receptors contribute to the regulation of resting blood pressure. Critical role of renin-angiotensin system (RAS) as regulator of blood pressure and sodium hemostasis.
- Published
- 1997
- Full Text
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3. Chronic immunoneutralization of brain angiotensin-(1-12) lowers blood pressure in transgenic (mRen2)27 hypertensive rats
- Author
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Debra I. Diz, Ellen N. Tommasi, Katsunori Isa, Carlos M. Ferrario, Detlev Ganten, Maria A. Garcia-Espinosa, Amy C. Arnold, Nancy T. Pirro, and Mark C. Chappell
- Subjects
Male ,medicine.medical_specialty ,Angiotensins ,Time Factors ,Physiology ,Transgene ,Central nervous system ,Angiotensinogen ,Drinking ,Hemodynamics ,Blood Pressure ,Immunoglobulin G ,Eating ,Physiology (medical) ,Internal medicine ,Renin ,Renin–angiotensin system ,medicine ,Animals ,biology ,Angiotensin 1 ,business.industry ,Body Weight ,Osmolar Concentration ,Brain ,Articles ,Infusion Pumps, Implantable ,Peptide Fragments ,Rats ,Disease Models, Animal ,Urodynamics ,medicine.anatomical_structure ,Endocrinology ,Blood pressure ,Hypertension ,biology.protein ,Rats, Transgenic ,Antibody ,business - Abstract
Angiotensin-(1-12) [ANG-(1-12)] is a newly identified peptide detected in a variety of rat tissues, including the brain. To determine whether brain ANG-(1-12) participates in blood pressure regulation, we treated male adult (mRen2)27 hypertensive rats (24–28 wk of age) with Anti-ANG-(1-12) IgG or Preimmune IgG via an intracerebroventricular cannula for 14 days. Immunoneutralization of brain ANG-(1-12) lowered systolic blood pressure (−43 ± 8 mmHg on day 3 and −26 ± 7 mmHg on day 10 from baseline, P < 0.05). Water intake was lower on intracereroventricular day 6 in the Anti-ANG-(1-12) IgG group, accompanied by higher plasma osmolality on day 13, but there were no differences in urine volume, food intake, or body weight during the 2-wk treatment. In Preimmune IgG-treated animals, there were no significant changes in these variables over the 2-wk period. The antihypertensive effects produced by endogenous neutralization of brain ANG-(1-12) suggest that ANG-(1-12) is functionally active in brain pathways regulating blood pressure.
- Published
- 2009
4. Differential modulation of baroreflex control of heart rate by neuron- vs. glia-derived angiotensin II
- Author
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Koji Sakai, Mark W. Chapleau, Martin D. Cassell, Satoshi Morimoto, and Curt D. Sigmund
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Nitroprusside ,Genetically modified mouse ,medicine.medical_specialty ,Sympathetic nervous system ,Angiotensins ,Physiology ,Angiotensinogen ,Blood Pressure ,Mice, Transgenic ,Biology ,Baroreflex ,Cardiovascular Physiological Phenomena ,Mice ,Phenylephrine ,Heart Rate ,Internal medicine ,Renin ,Heart rate ,Renin–angiotensin system ,Genetics ,medicine ,Animals ,Humans ,Neurons ,Differential modulation ,Angiotensin II ,Brain ,Immunohistochemistry ,Propranolol ,Endocrinology ,medicine.anatomical_structure ,cardiovascular system ,Neuron ,Peptides ,Neuroglia ,hormones, hormone substitutes, and hormone antagonists ,circulatory and respiratory physiology - Abstract
We developed transgenic mice with targeted expression of human renin (hREN) and human angiotensinogen (hAGT) to either neurons (N-AII mice) or glia (G-AII mice) to test the hypothesis that neuronal and glial ANG II may have differential function. Since baseline blood pressure (BP) did not differ between the models (109 ± 3 vs. 114 ± 4 mmHg), we stressed the BP regulatory pathway by measuring the heart rate (HR) (baroreflex) response to phenylephrine- and nitroprusside-induced changes in arterial BP. The midpoint of the baroreflex curve (BP50) was reset to a significantly higher BP in N-AII mice (131 ± 5 mmHg) compared with littermate controls (115 ± 3 mmHg). Baroreflex gain (slope of BP-HR relation) was similar in N-AII and control mice (12 ± 1 vs. 14 ± 2 beats·min−1·mmHg−1). In contrast, G-AII mice exhibited less of an increase in BP50 (125 ± 5 mmHg) but a larger decrease in baroreflex gain (8 ± 1 beats·min−1·mmHg−1) compared with both control and N-AII mice. Differences in BP50 and gain between N-AII, G-AII, and control mice persisted after parasympathetic blockade with atropine but were eliminated after sympathetic blockade with propranolol, indicating the effects of ANG II were selective for cardiosympathetic arm of the reflex. ANG II-like immunoreactivity was observed more prominently around the paraventricular nucleus and nucleus tractus solitarii in G-AII mice but more prominently in the ventrolateral medulla in N-AII mice. We conclude that ANG II differentially modulates baroreflex control of HR in mice producing ANG II in neurons vs. glia, and its differential function may reflect regional differences in the production of ANG II in cardiovascular control nuclei of the brain.
- Published
- 2004
5. Comparison of effects of exercise and diuretic on left ventricular geometry, mass, and insulin resistance in older hypertensive adults
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Linda R. Peterson, Robert J. Spina, Christopher J Koenig, Ali A. Ehsani, Christa R Florence, and Morton R. Rinder
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Blood Glucose ,Male ,medicine.medical_specialty ,Angiotensins ,Physiology ,Sodium Chloride Symporter Inhibitors ,Hemodynamics ,Blood Pressure ,Physical exercise ,Ventricular Dysfunction, Left ,Oxygen Consumption ,Insulin resistance ,Hydrochlorothiazide ,Heart Rate ,Physiology (medical) ,Internal medicine ,Renin ,Heart rate ,medicine ,Hyperinsulinemia ,Humans ,Plasma Volume ,Exercise physiology ,Diuretics ,Exercise ,Aged ,business.industry ,Blood Pressure Monitoring, Ambulatory ,medicine.disease ,Lipids ,Blood pressure ,Endocrinology ,Hypertension ,Body Composition ,Cardiology ,Female ,Hypertrophy, Left Ventricular ,Insulin Resistance ,business ,medicine.drug - Abstract
To compare the effects of exercise training and hydrochlorothiazide on left ventricular (LV) geometry and mass, blood pressure (BP), and hyperinsulinemia in older hypertensive adults, we studied 28 patients randomized either to a group (age 66.4 ± 1.3 yr; n = 16) that exercised or to a group (age 65.3 ± 1.2 yr; n = 12) that received hydrochlorothiazide for 6 mo. Endurance exercise training induced a 15% increase in peak aerobic power. The reduction in systolic BP was twofold greater with thiazide than with exercise (26.6 ± 12.2 vs. 11.5 ± 10.9 mmHg). Exercise and thiazide reduced LV wall thickness, LV mass index (14% in each group), and the LV wall thickness-to-radius ratio ( h/ r) similarly (exercise: before 0.48 ± 0.2, after 0.42 ± 0.01; thiazide: before 0.47 ± 0.04, after 0.40 ± 0.04; P = 0.017). The reductions in systolic BP and h/ r were correlated in the exercise group ( r = 0.70, P = 0.005) but not in the thiazide group. Exercise training reduced glucose-stimulated hyperinsulinemia (before: 13.65 ± 2.6 vs. 9.84 ± 1.5 mU·ml−1·min; P = 0.04) and insulin resistance. Thiazide did not affect plasma insulin levels. The results suggest that although exercise is less effective in reducing systolic BP than thiazide, it can induce regression of LV hypertrophy similar in magnitude to thiazide. Unlike hydrochlorothiazide, exercise training can improve insulin resistance and aerobic capacity in older hypertensive people.
- Published
- 2004
6. Intrauterine growth restriction in rats is associated with hypertension and renal dysfunction in adulthood
- Author
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Jean St-Louis, Michèle Brochu, Marie-Claude Battista, and Luc L. Oligny
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Male ,Aging ,medicine.medical_specialty ,Angiotensins ,Physiology ,Heart Ventricles ,Endocrinology, Diabetes and Metabolism ,Urinary system ,Kidney Glomerulus ,Intrauterine growth restriction ,Renal function ,Blood Pressure ,Kidney ,Kidney Function Tests ,Rats, Sprague-Dawley ,Renin-Angiotensin System ,chemistry.chemical_compound ,Pregnancy ,Physiology (medical) ,Internal medicine ,Renin ,Renin–angiotensin system ,medicine ,Animals ,RNA, Messenger ,reproductive and urinary physiology ,Creatinine ,Fetal Growth Retardation ,business.industry ,Body Weight ,Organ Size ,medicine.disease ,female genital diseases and pregnancy complications ,Rats ,medicine.anatomical_structure ,Blood pressure ,Endocrinology ,chemistry ,Hypertension ,embryonic structures ,Gestation ,Female ,Kidney Diseases ,Corticosterone ,business ,Atrial Natriuretic Factor - Abstract
Epidemiological studies have produced evidence that unfavorable intrauterine environments during fetal life may lead to adverse outcomes in adulthood. We have previously shown that a low-sodium diet, given to pregnant rats over the last week of gestation, results in intrauterine growth restriction (IUGR). We hypothesize that pups born with IUGR are more susceptible to the development of hypertension in adulthood. IUGR fetuses and rats aged 1 wk were characterized for organ growth and renal morphogenesis. The adults (12 wk) were evaluated for weight, systolic blood pressure, activity of the renin-angiotensin-aldosterone system (RAAS), and renal function; hearts and kidneys underwent a histological examination. Brain and cardiac ventricle-to-body ratios were increased in IUGR fetuses compared with age-matched controls, whereas the kidney-to-body ratio was unchanged. Systolic blood pressure was elevated in both IUGR male and female adults. Plasma aldosterone levels were not correlated with increased plasma renin activity. Moreover, urinary sodium was decreased, whereas plasma urea was elevated in both males and females, and creatinine levels were augmented only in females, suggesting a glomerular filtration impairment in IUGR. In our model of IUGR induced by a low-sodium diet given to pregnant rats, high blood pressure, alteration of the RAAS, and renal dysfunction are observed in adult life. Differences observed between male and female adults suggest the importance of gender in outcomes in adulthood after IUGR.
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- 2002
7. Renal and adrenal responses to [des-Asp1]angiotensin I in the dog
- Author
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Ronald H. Freeman, M. C. Khosla, and James O. Davis
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medicine.medical_specialty ,Mean arterial pressure ,Angiotensins ,Physiology ,Renal function ,Blood Pressure ,Kidney ,chemistry.chemical_compound ,Dogs ,Internal medicine ,Renin ,Renin–angiotensin system ,medicine ,Animals ,Aldosterone ,Angiotensin III ,Angiotensin II ,Filtration fraction ,Endocrinology ,chemistry ,Regional Blood Flow ,Renal blood flow ,Renal physiology ,Female ,Angiotensin I - Abstract
There is evidence for the endogenous generation of [des-Asp1]angiotensin II (AIII) from a nonapeptide precursor, [des-Asp1]angiotensin I ([des-Asp1]AI). In the present study, the effects of equipressor doses of exogeneously administered [des-Asp1]AI and AIII on renal function and plasma aldosterone concentration were compared. Intravenous infusion of [des-Asp1]AI (75 ng/kg min-1 for 40 min) decreased renin secretion, renal blood flow, creatinine clearance, and sodium and potassium excretion in dogs. Infusion of AIII at one-third of the rate of [des-Asp1]AI (25 ng/kg min-1) produced comparable decreases in these same parameters. Filtration fraction was increased with both peptides. Both peptides also increased plasma aldosterone concentration to the same extent. A bolus injection (5 mg i.v.) of the converting enzyme inhibitor SQ 20,881 completely reversed the mean arterial pressure and renal blood flow responses to [des-Asp1]AI, but did not alter these responses to AIII. These data are consistent with the concept that endogenous generation of AIII from [des-Asp1]AI can occur via the action of converting enzyme on this substance.
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- 1978
8. Synergism of intraventricular NaCl infusion and subpressor angiotensins in rats
- Author
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Katsuhiko Kohara, Atsuhiro Otsuka, Hiroshi Mikami, M. C. Khosla, Yuichi Kumahara, Ogihara T, and Katsutoshi Katahira
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Male ,medicine.medical_specialty ,Vasopressin ,Angiotensins ,Arginine ,Physiology ,Blood Pressure ,Sodium Chloride ,Peptide hormone ,chemistry.chemical_compound ,Physiology (medical) ,Internal medicine ,Renin ,Renin–angiotensin system ,Prazosin ,medicine ,Animals ,Injections, Intraventricular ,Saline Solution, Hypertonic ,Chemistry ,Drug Synergism ,Rats, Inbred Strains ,Angiotensin II ,Rats ,Arginine Vasopressin ,Endocrinology ,Injections, Intravenous ,Tonicity ,Hexamethonium ,Cardiology and Cardiovascular Medicine ,hormones, hormone substitutes, and hormone antagonists ,medicine.drug - Abstract
The effect of selective salt infusion to the central nervous system on the blood pressure (BP) regulation was examined in male Wistar rats. Hypertonic NaCl (0.8 M, 1 microliter/h) was infused into the lateral ventricle concomitantly with intravenous infusion of a subpressor dose (5.4 pmol.kg-1.min-1) of angiotensin II (ANG II) or its analogues for 7 days using osmotic minipumps. The BP was not increased by intracerebroventricular infusion of NaCl alone at this dose but was significantly and consistently increased by concomitant intravenous infusion of ANG II or its analogues. The increases in the BP over the base-line values on day 7 in groups on infusions of ANG II, ANG III, and pentasarcosyl-ANG II [(Sar)5ANG II] were 29 +/- 5 mmHg (n = 9, P less than 0.05), 8 +/- 2 mmHg (n = 8, P less than 0.05), and 19 +/- 3 mmHg (n = 6, P less than 0.05), respectively. The responses to hexamethonium, prazosin, and antagonists of arginine vasopressin and ANG II were examined in separate sets of conscious and unrestrained animals that had received intracerebroventricular infusion of NaCl and intravenous infusion of ANG II for the preceding 6 days. These animals showed significantly greater depressor responses only to hexamethonium and prazosin than control. These results indicate that the pressor effect of continuous and concomitant administration of intracerebroventricular NaCl and intravenous ANG II is mainly due to activation of the sympathetic nerve function. Synergism of the effects of selective central sodium administration and a subpressor dose of ANG II in the central nervous system is suggested.
- Published
- 1989
9. The renal kallikrein-kinin system
- Author
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O. A. Carretero and Alfonso G. Scicli
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medicine.medical_specialty ,Angiotensins ,Physiology ,Renal function ,Blood Pressure ,Vasodilation ,Kinins ,Kidney ,Renal kallikrein ,Internal medicine ,Renin ,medicine ,Animals ,Humans ,Aldosterone ,Nephritis ,business.industry ,Sodium ,Kidney metabolism ,Acute Kidney Injury ,Kinin ,Rats ,Endocrinology ,Blood pressure ,Renal physiology ,Hypertension ,Prostaglandins ,Kidney Failure, Chronic ,Kallikreins ,Rabbits ,business ,Glomerular Filtration Rate - Published
- 1980
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