| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Physiology and Pharmacology and The Hypertension Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1083; and Max Delbruck Center for Molecular Medicine, 01115 Berlin-Buch, Germany
We previously
demonstrated that mRen-2 transgenic [Tg(+)] rats are
sensitive to chronic high NaCl intake, showing increased arterial
pressure and vasopressin (VP) secretion. In this study, we determined
the effect of a chronic osmotic challenge, 4 days of drinking 2% NaCl,
on direct arterial blood pressure, heart rate, fluid-electrolyte
balance, circadian rhythm of mean arterial pressure (MAP), and changes
in plasma VP and catecholamines. Under baseline conditions, male Tg(+)
rats showed a significant shift in the peak in circadian MAP into the
light portion of the day-night cycle. Substitution of 2% NaCl for
drinking water caused a rapid increase in MAP, 20 ± 5 mmHg in Tg(+)
rats within 6 h. Whereas the amplitude of circadian MAP fluctuations
increased in salt-loaded Tg(+) rats, there was no significant change in
the circadian timing of peak MAP with salt loading. Tg(+) rats showed
exaggerated osmotic-induced increases in plasma VP, norepinephrine
(NE), and epinephrine (Epi) compared with Tg(
) rats. Plasma NE
and Epi were increased two- and fourfold, respectively, in the
hypertensive rats with no significant change in the Tg() rats.
Intravenous administration of a VP antagonist did not alter arterial
pressure in either Tg(+) or Tg() rats. Tg(+) and Tg()
rats showed a positive sodium balance with no significant difference
observed between the groups. Tg(+) rats showed a significant increase
in salt consumption, plasma sodium, osmolality, and hematocrit,
accompanied by a negative water balance. We conclude that Tg(+) rats
are sensitive to acute and chronic osmotic stimuli in terms of blood
pressure, fluid-electrolyte balance, and plasma VP and catecholamines.
Whereas elevated plasma VP does not contribute to the hypertensive
response, increased sympathetic drive may mediate the salt-induced
blood pressure changes in this model.
hypertension; renin; vasopressin; catecholamines; osmotic challenge
This article has been cited by other articles:
|
|
 |
|
  N. Li, L. Chen, F. Yi, M. Xia, and P.-L. Li Salt-Sensitive Hypertension Induced by Decoy of Transcription Factor Hypoxia-Inducible Factor-1{alpha} in the Renal Medulla Circ. Res., May 9, 2008; 102(9): 1101 - 1108. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. C. Chappell, L. M. Yamaleyeva, and B. M. Westwood Estrogen and salt sensitivity in the female mRen(2).Lewis rat Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2006; 291(5): R1557 - R1563. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. C. Blendea, D. Jacobs, C. S. Stump, S. I. McFarlane, C. Ogrin, G. Bahtyiar, S. Stas, P. Kumar, Q. Sha, C. M. Ferrario, et al. Abrogation of oxidative stress improves insulin sensitivity in the Ren-2 rat model of tissue angiotensin II overexpression Am J Physiol Endocrinol Metab, February 1, 2005; 288(2): E353 - E359. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. Fang, S. H. Carlson, N. Peng, and J. M. Wyss Circadian rhythm of plasma sodium is disrupted in spontaneously hypertensive rats fed a high-NaCl diet Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2000; 278(6): R1490 - R1495. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Li, S. H. Sur, R. E. Mistlberger, and M. Morris Circadian blood pressure and heart rate rhythms in mice Am J Physiol Regulatory Integrative Comp Physiol, February 1, 1999; 276(2): R500 - R504. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
