Obesity depresses baroreflex control of renal sympathetic nerve activity and heart rate in Sprague Dawley rats: role of the renal innervation

2015 ◽  
Vol 214 (3) ◽  
pp. 390-401 ◽  
Author(s):  
S. A. Khan ◽  
M. Z. A. Sattar ◽  
N. A. Abdullah ◽  
H. A. Rathore ◽  
M. H. Abdulla ◽  
...  
Keyword(s):  
Heart Rate ◽  
Sympathetic Nerve Activity ◽  
Sprague Dawley ◽  
Nerve Activity ◽  
Baroreflex Control ◽  
Renal Sympathetic Nerve Activity ◽  
Sprague Dawley Rats ◽  
Renal Innervation ◽  
Renal Sympathetic

Glucocorticoids reduce responses to AMPA receptor activation and blockade in nucleus tractus solitarius

2003 ◽  
Vol 284 (5) ◽  
pp. H1751-H1761 ◽  
Author(s):  
Sylvan S. Shank ◽  
Deborah A. Scheuer
Keyword(s):  
Arterial Pressure ◽  
Ampa Receptors ◽  
Sympathetic Nerve Activity ◽  
Nucleus Tractus Solitarius ◽  
Receptor Activation ◽  
Sprague Dawley ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Sprague Dawley Rats ◽  
Renal Sympathetic

We tested the hypothesis that glucocorticoids attenuate changes in arterial pressure and renal sympathetic nerve activity (RSNA) in response to activation and blockade of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors within the nucleus of the solitary tract (NTS). Experiments were performed in Inactin-anesthetized male Sprague-Dawley rats treated for 7 ± 1 days with a subcutaneous corticosterone (Cort) pellet or in control rats. Baseline mean arterial pressure (MAP) was significantly higher in Cort-treated rats (109 ± 2 mmHg, n = 39) than in control rats (101 ± 1 mmHg, n = 48, P < 0.05). In control rats, microinjection of AMPA (0.03, 0.1, and 0.3 pmol/100 nl) into the NTS significantly decreased MAP at all doses and decreased RSNA at 0.1 and 0.3 pmol/100 nl. Responses to AMPA in Cort-treated rats were attenuated at all doses of AMPA ( P < 0.05). Responses to the AMPA-kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) were also significantly reduced in Cort-treated rats relative to control rats. Blockade of glucocorticoid type II receptors with mifepristone significantly enhanced responses to CNQX in both control and Cort rats. We conclude that glucocorticoids attenuate MAP and RSNA responses to activation and blockade of AMPA receptors in the NTS.

Baroreflex control of renal sympathetic nerve activity and heart rate in near-term fetal sheep

2011 ◽  
Vol 96 (8) ◽  
pp. 736-744 ◽  
Author(s):  
Lindsea C. Booth ◽  
Alistair J. Gunn ◽  
Simon C. Malpas ◽  
Carolyn J. Barrett ◽  
Joanne O. Davidson ◽  
...  
Keyword(s):  
Heart Rate ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Nerve Activity ◽  
Baroreflex Control ◽  
Fetal Sheep ◽  
Renal Sympathetic Nerve Activity ◽  
Renal Sympathetic Nerve ◽  
Near Term ◽  
Renal Sympathetic

Increase in sympathetic activity with age. I. Role of impairment of arterial baroreflexes

1991 ◽  
Vol 260 (4) ◽  
pp. H1113-H1120 ◽  
Author(s):  
G. Hajduczok ◽  
M. W. Chapleau ◽  
S. L. Johnson ◽  
F. M. Abboud
Keyword(s):  
Sympathetic Nerve Activity ◽  
Carotid Sinus ◽  
Conscious State ◽  
Bolus Administration ◽  
Arterial Baroreflex ◽  
Nerve Activity ◽  
Baroreflex Control ◽  
Renal Sympathetic Nerve Activity ◽  
Renal Sympathetic

The purpose of this study was to evaluate changes in arterial baroreflex function with aging. Mean arterial pressure (MAP) obtained in the awake state was 110 +/- 7 mmHg in the young animals (1 yr; n = 5) and 128 +/- 6 mmHg in the old beagles (11 yr; n = 11) (P less than 0.05). In response to bolus administration of varying doses of phenylephrine and nitroglycerin in the conscious state, the slope relating heart rate (HR) to MAP was attenuated significantly in the old animals compared with the young (-0.87 +/- 0.30 vs. -2.35 +/- 0.44 beats.min-1.mmHg-1; P less than 0.05). After atropine, the baroreflex control of HR was abolished in both groups. After anesthesia and sectioning of the aortic depressor nerves, and with isolated carotid sinus pressures (CSP) held at 50 mmHg, absolute renal sympathetic nerve activity (RSNA) was significantly greater in the old (368 +/- 40 Hz) vs. the young animals (41 +/- 9 Hz). In the old, the gains of baroreflex inhibition of MAP (0.78 +/- 0.09) and normalized RSNA (0.38 +/- 0.14%/mmHg) during increases in CSP were decreased significantly compared with the young (MAP, 1.16 +/- 0.17 mmHg, and RSNA, 0.72 +/- 0.06%/mmHg). In a subgroup of old normotensive animals (n = 5), the baroreflex gain of RSNA was still attenuated (0.43 +/- 0.11%/mmHg) compared with the young. The reflex reduction in absolute RSNA as a function of baseline RSNA was also impaired in old vs. young beagles.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucocorticoids modulate baroreflex control of renal sympathetic nerve activity

2001 ◽  
Vol 280 (5) ◽  
pp. R1440-R1449 ◽  
Author(s):  
Deborah A. Scheuer ◽  
Steven W. Mifflin
Keyword(s):  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Gain Coefficient ◽  
Sprague Dawley ◽  
Nerve Activity ◽  
Baroreflex Control ◽  
Renal Sympathetic Nerve Activity ◽  
Renal Sympathetic Nerve ◽  
Baroreflex Function ◽  
Renal Sympathetic

Experiments were performed to determine the effects of glucocorticoids on arterial baroreceptor reflex control of renal sympathetic nerve activity (RSNA). Intravenous infusions of phenylephrine and nitroprusside were used to produce graded changes in arterial pressure (AP) in Inactin-anesthetized male Sprague-Dawley rats. Baroreflex control of RSNA was determined during a baseline period and 2 and 3 h after administration of the glucocorticoid type II receptor antagonist Mifepristone (30 mg/kg sc) or vehicle (oil). Corticosterone (cort) treatment (100 mg cort pellet sc for 2–3 wk) increased baseline AP from 115 ± 2 to 128 ± 1 mmHg. Cort treatment also decreased the gain coefficient and increased the midpoint of the baroreflex curve. Treatment of cort rats with Mifepristone decreased AP within 2 h and increased the gain coefficient and decreased the midpoint of the baroreflex function curve back toward values measured in control rats. Mifepristone altered the baroreflex function curve even when AP was maintained at baseline levels. Therefore, these data demonstrate for the first time that glucocorticoids can modulate baroreflex control of RSNA by a mechanism that is, in part, independent of changes in AP.

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