|
|
||||||||
Department of Pharmacology, The University of Missouri, Kansas City, Missouri 64108
We tested the hypothesis that
glucocorticoids attenuate changes in arterial pressure and renal
sympathetic nerve activity (RSNA) in response to activation and
blockade of
-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.
hypertension; corticosterone; baroreceptor reflex; glutamate
This article has been cited by other articles:
![]() |
P. J. Mueller and E. M. Hasser Putative role of the NTS in alterations in neural control of the circulation following exercise training in rats Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2006; 290(2): R383 - R392. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. A. Scheuer, A. G. Bechtold, S. S. Shank, and S. F. Akana Glucocorticoids act in the dorsal hindbrain to increase arterial pressure Am J Physiol Heart Circ Physiol, January 1, 2004; 286(1): H458 - H467. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |