scholarly journals Vascular responsiveness in adrenalectomized rats with corticosterone replacement

1989 ◽  
Vol 256 (5) ◽  
pp. H1274-H1281 ◽  
Author(s):  
D. N. Darlington ◽  
K. Kaship ◽  
L. C. Keil ◽  
M. F. Dallman
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Arterial Blood Pressure ◽  
Body Weight Gain ◽  
Arterial Blood ◽  
Thymus Weight ◽  
Vascular Responsiveness ◽  
Vascular Sensitivity ◽  
Four Levels ◽  
Adrenalectomized Rats

To determine under resting, unstressed conditions the circulating glucocorticoid concentrations that best maintain sensitivity of the vascular smooth muscle and baroreceptor responses to vasoactive agents, rats with vascular cannulas were sham-adrenalectomized (sham) or adrenalectomized (ADRX) and provided with four levels of corticosterone replacement (approximately 100 mg fused pellets of corticosterone: cholesterol 0, 20, 40, and 80% implanted subcutaneously at the time of adrenal surgery). Changes in vascular and baroreflex responses were determined after intravenous injection of varying doses of phenylephrine and nitroglycerin with measurement of arterial blood pressure and heart rate in the conscious, chronically cannulated rats. Vascular sensitivity was decreased, and resting arterial blood pressure tended to be decreased in the adrenalectomized rats; both were restored to normal with levels of corticosterone (40%), which also maintained body weight gain, thymus weight, and plasma corticosteroid binding globulin concentrations at normal values. The baroreflex curve generated from the sham group was different from the curves generated from the ADRX+0, 20, and 40% groups, but not different from that of the ADRX+80% group, suggesting that the baroreflex is maintained by higher levels of corticosterone than are necessary for the maintenance of the other variables. These data demonstrate that physiological levels of corticosterone (40% pellet) restore vascular responsiveness, body weight, thymus weight, and transcortin levels to normal in ADRX rats, whereas higher levels (80% pellet) are necessary for restoration of the baroreflex.

Post-Adrenalectomy Hypotension in Rats; Absence of Baroreflex Resetting or Effect of Naloxone

1983 ◽  
Vol 64 (4) ◽  
pp. 371-376 ◽  
Author(s):  
S. M. Gardiner ◽  
T. Bennett
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Tap Water ◽  
Sinus Node ◽  
Pulse Interval ◽  
Baroreflex Control ◽  
Systemic Arterial Blood Pressure ◽  
Arterial Blood ◽  
Blood Pressures ◽  
Adrenalectomized Rats

1. Male Wistar rats were either bilaterally adrenalectomized or sham-operated, and given 1% sodium chloride solution instead of tap water to drink. Seven days later, arterial blood pressures were recorded directly from conscious freely moving rats. 2. Systolic and diastolic blood pressures were significantly lower in the adrenalectomized rats, whereas heart rates were significantly higher than in sham-operated animals. The tachycardia was due to a combination of sympathetic hyperactivity and reduced vagal tone, which may have been reflex responses to a reduction in effective blood volume. 3. Baroreflex control of the sinus node was assessed from the pulse interval responses to rises (induced by methoxamine) or falls (induced by glyceryl trinitrate or sodium nitroprusside) in systemic arterial blood pressure. The relation between pulse interval and systolic blood pressure was described by the same curve in sham-operated and adrenalectomized rats, indicating that, in the latter, there was no change in baroreflex setting or sensitivity. 4. Intravenous administration of naloxone (2mg/kg) had no effect on systemic arterial blood pressure in adrenalectomized rats, suggesting that endogenous opiates were not contributing to the hypotension.

Exaggerated natriuresis during clamping of systemic NO supply in healthy young men

2011 ◽  
Vol 122 (2) ◽  
pp. 63-73 ◽  
Author(s):  
Jane A. Simonsen ◽  
Mona S. Rasmussen ◽  
Werner Vach ◽  
Poul F. Høilund-Carlsen ◽  
Peter Bie
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Arterial Blood Pressure ◽  
Sodium Excretion ◽  
Volume Expansion ◽  
Renal Plasma Flow ◽  
Peripheral Resistance ◽  
Young Men ◽  
System Activity ◽  
Arterial Blood

NO (nitric oxide) may be involved in fluid homoeostasis. We hypothesized that increases in NO synthesis contribute to acute, saline-induced natriuresis, which, therefore, should be blunted when NO availability is stabilized. Young men were studied during simultaneous infusions of L-NAME [NG-nitro-L-arginine methyl ester; bolus of 750 μg·kg−1 of body weight and 8.3 μg·min−1·kg−1 of body weight] and SNP (sodium nitroprusside), the latter at a rate preventing L-NAME from increasing total peripheral resistance (‘NO-clamping’). Slow volume expansion (saline, 20 μmol of NaCl·min−1·kg−1 of body weight for 3 h) was performed with and without concomitant NO-clamping. NO-clamping itself decreased RPF (renal plasma flow; P~0.02) and tended to decrease arterial blood pressure [MABP (mean arterial blood pressure)]. Volume expansion markedly decreased the plasma levels of renin, AngII (angiotensin II) and aldosterone (all P<0.001), while MABP (oscillometry), heart rate, cardiac output (impedance cardiography), RPF (by p-aminohippurate), GFR [glomerular filtration rate; by using 51Cr-labelled EDTA] and plasma [Na+] and [K+] remained constant. Volume expansion increased sodium excretion (P<0.02) at constant filtered load, but more so during NO-clamping than during control (+184% compared with 52%; P<0.0001). Urinary nitrate/nitrite excretion increased during volume expansion; plasma cGMP and plasma vasopressin were unchanged. The results demonstrate that NO-clamping augments sodium excretion in response to volume expansion at constant MABP and GFR, reduced RPF and decreased renin system activity, a response termed hypernatriuresis. The results indicate that mediator(s) other than MABP, RPF, GFR and renin system activity contribute significantly to the homoeostatic response to saline loading, but the specific mechanisms of hypernatriuresis remain obscure.

The contribution of the autonomic nervous system, the renin-angiotensin system and vasopressin to the maintenance of arterial blood pressure in adrenalectomized Wistar rats

1986 ◽  
Vol 71 (4) ◽  
pp. 357-365 ◽  
Author(s):  
S. M. Gardiner ◽  
T. Bennett
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Free Water ◽  
Renin Angiotensin System ◽  
Renin Angiotensin ◽  
Autonomic Nervous ◽  
Arterial Blood ◽  
Cardiovascular Actions ◽  
Ganglionic Transmission ◽  
Adrenalectomized Rats

1. Factors contributing to the maintenance of resting arterial blood pressure in sham-operated and adrenalectomized rats were assessed 14 weeks after operation; some animals were given 1% NaCl to drink throughout, and some animals were given sodium-free water instead of 1% NaCl for 2 days before the experiment. 2. Inhibition of the renin-angiotensin (ANG) system (with captopril) and of the cardiovascular actions of vasopressin [with 1-(β-mercapto-β,β-cyclopentamethylenepropionic acid), 8-d-arginine vasopressin (d(CH2)5DAVP)] had no hypotensive effects in sham-operated rats under any conditions, but antagonism of nicotinic ganglionic transmission (with pentolinium) caused a prompt fall in blood pressure. During combined administration of captopril, d(CH2)5DAVP and pentolinium to sham-operated rats, there was no significant recovery of blood pressure. 3. Adrenalectomized rats drinking 1% NaCl showed a marked hypotension and tachycardia in response to captopril, but d(CH2)5DAVP had little effect, whether administered before or after captopril. Addition of pentolinium rendered these animals more hypotensive man the sham-operated rats. 4. Adrenalectomized rats drinking sodium-free water for 2 days were hypotensive and blood pressures were lowered further by d(CH2)5DAVP or captopril under these conditions; there was no accompanying tachycardia. 5. The results indicate that, in chronically adrenalectomized rats drinking 1% NaCl, blood pressure is maintained by autonomic nervous and renin-ANG systems with no discernible contribution from the peripheral cardiovascular actions of vasopressin. However, the latter contribute importantly to the support of blood pressure when the adrenalectomized rats are rendered hypovolemic and hypotensive by substitution of sodium-free water to drink.

scholarly journals The physiological significance of body weight at birth for subsequent age periods of life

2012 ◽  
Vol 93 (2) ◽  
pp. 330-334
Author(s):  
Yu D Karpenko
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Birth Weight ◽  
Arterial Blood Pressure ◽  
Random Variable ◽  
The Body ◽  
Examination Period ◽  
Arterial Blood ◽  
Cardio Vascular ◽  
Birth Body Weight

Aim. To study the significance of the features of early development of a child’s body, estimated on the basis of the anthropometric data at birth for subsequent age periods. Methods. The study involved practically healthy 1-5 year students with normal birth weight, 439 males and 112 females, mean age was 21.13±±0.08 years. Measurements of systolic and diastolic arterial blood pressure were performed using an automated tonometer, heart rate variability was studied on a computer electrocardiography device in accordance with the generally accepted guidelines. Conducted was a multiple regression analysis, in which as an independent random variable were the age and height of the mother, the sex of the newborn, the serial number of delivery, and as a dependent variable - the birth body weight. Results. Established was a significant correlation between birth body weight and body length (β=0.163; p=0.000), maternal age (β=0.137; p=0.001), month (season) of birth (β=-0.2012; p=0.003) and sex (β=-0.1009; p=0.003) of the child. Noted was a correlation of the respiration rate with the body weight at birth both during the semester period (r=-0.2; p=0.05) and during the examination period (r=0.26; p=0.03). Conclusion. During the examination period the correlation between birth weight and the values of functional parameters (respiratory rate, tidal volume, arterial blood pressure) of the students increases, therefore, birth body weight among the surveyed students was a predictor of the functional state of the respiratory system, cardio-vascular and autonomic nervous systems.

scholarly journals Ameliorative effect of apelin-13 against renal complications in L-NAME-induced preeclampsia in rats

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11110
Author(s):  
Reham Z. Hamza ◽  
Abdel Aziz A. Diab ◽  
Mansour H. Zahra ◽  
Ali K. Asalah ◽  
Mai S. Attia ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Histopathological Examination ◽  
Female Rats ◽  
Serum Urea ◽  
Pregnant Rats ◽  
Arterial Blood ◽  
Total Urine

Pre-eclampsia (PE) accompanying acute liver and kidney injury has remained a master cause of both fetal and maternal mortality and morbidity. Vasoactive mediators, oxidative stress and inflammatory imbalanceshave an important role in PE pathogenesis. Apelin is an adipokine that improves endothelial dysfunction; has anti-inflammatory and antioxidant effects; moreover, its level reduced during PE. This study aimed to explore the effects of apelin-13 administration on preeclampsia-associated renal dysfunction and proteinuria. Thirty-three pregnant female rats were divided into three groups; group: 1 (normal pregnant rats), group: 2 (preeclamptic rats); where rats were injected subcutaneously with 75 mg L-NAME/ kg body weight/day beginning from 9th to 20th day of pregnancy andgroup 3 (apelin-13 treated preeclamptic rats); In which L-NAME-induced preeclamptic rats were subcutaneously injected with 6 × 10−8 mol apelin-13/kg body weight/twice daily starting from 6th to 20th day of pregnancy. In all groups, mean arterial blood pressure, total urine protein, serum urea, creatinine, nitric oxide (NO), endothelin-1 (ET-1), interleukin–6 (IL-6) and malondialdhyde (MDA) were measured. Histopathological examination of kidney tissues was also done. preeclamptic rats showed significantly increased mean arterial blood pressure, total urine proteins, serum urea, creatinine, ET-1, IL-6, and MDA, but revealed a significantly decreased serum NO level. On the other hand, apelin treatment significantly improved these parameters together with amelioration of kidney histoarchitecture in the treated group. In conclusion, apelin may be a potentially curative candidate for prohibiting kidney damage and have a therapeutic benefit in PE rat models.

Corticosterone: narrow range required for normal body and thymus weight and ACTH

1985 ◽  
Vol 249 (5) ◽  
pp. R527-R532 ◽  
Author(s):  
S. F. Akana ◽  
C. S. Cascio ◽  
J. Shinsako ◽  
M. F. Dallman
Keyword(s):  
Body Weight ◽  
Negative Feedback ◽  
Narrow Range ◽  
Body Weight Gain ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Acth Secretion ◽  
Negative Feedback Regulation ◽  
Thymus Weight ◽  
Adrenalectomized Rats

ACTH secretion appears to be under fairly tight negative feedback control by corticosteroids secreted from the adrenal cortex. In these studies we determined the circulating levels of a constant corticosterone signal that best restored body weight gain, thymus weight and ACTH levels to normal in bilaterally adrenalectomized rats given saline to drink. Young male rats were treated at the time of adrenalectomy with subcutaneously implanted pellets of wax or various ratios of corticosterone-cholesterol. Sham-adrenalectomized rats and adrenalectomized rats given corticosterone in the drinking fluid served as comparison groups. Rats were killed 3, 7, or 14 days after adrenalectomy. There was no difference in levels of plasma corticosterone in the morning and in the evening in pellet-implanted rats in contrast to the diurnal variation in the reference groups. Circulating corticosterone levels that best restored body weight, thymus weight, and resting and stress-induced ACTH levels to normal ranged between 4.5 and 7.4 micrograms/dl. Plasma corticosterone levels of 8-11 micrograms/dl were excessive and levels of 2-4 micrograms/dl were not adequate. We conclude that there is a very narrow range of plasma corticosterone compatible with normal growth rate, thymus mass and ACTH secretion. These results reveal the necessity for strict negative feedback regulation of ACTH secretion by corticosteroids.

scholarly journals High-Normal Arterial Blood Pressure in Children With Excess Body Weight

2016 ◽  
Vol 26 (4) ◽  
Author(s):  
Malgorzata Kolpa ◽  
Agnieszka Jankowicz-Szymanska ◽  
Beata Jurkiewicz
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Arterial Blood Pressure ◽  
Excess Body Weight ◽  
Arterial Blood
Sign in / Sign up

Export Citation Format

Share Document