This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ito, S. Articles by Sved, A. F. Search for Related Content PubMed PubMed Citation Articles by Ito, S. Articles by Sved, A. F. Related Collections Other hypertension Hypertension - basic studies Autonomic, reflex, and neurohumoral control of circulation

(Hypertension. 2001;37:687.)
© 2001 American Heart Association, Inc.

Scientific Contributions

Tonic Excitatory Input to the Rostral Ventrolateral Medulla in Dahl Salt-Sensitive Rats

Satoru Ito; Kazutoshi Komatsu; Kazuyoshi Tsukamoto; Alan F. Sved

From the Second Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan, and the Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pa (A.F.S.).

Correspondence to Dr Alan F. Sved, 446 Crawford Hall, University of Pittsburgh, Pittsburgh, PA 15260. E-mail: sved{at}pitt.edu

The goal of the present study was to test the hypothesis that the balance of tonic excitation and inhibition of vasomotor neurons in the rostral ventrolateral medulla (RVLM) driven by excitatory amino acid (EAA)–mediated inputs to the RVLM is shifted toward excitation in Dahl salt-sensitive (DS) rats compared with Dahl salt-resistant (DR) rats. Glutamate and the EAA antagonist kynurenic acid were microinjected into the RVLM of chloralose-anesthetized DS and DR rats maintained on diets containing either 0.3% NaCl or 8.0% NaCl. DS rats had a higher arterial pressure than DR rats, and this difference was greatly exaggerated by high dietary salt intake. Bilateral injection of kynurenic acid (2.7 nmol) into the RVLM decreased mean arterial pressure by 16±2 mm Hg in DS rats fed a diet containing 0.3% NaCl, and this effect was significantly larger in DS rats fed the high-salt diet (40±2 mm Hg). In contrast, injections of kynurenic acid into the RVLM did not significantly decrease arterial pressure in DR rats fed either diet. In DR rats, the pressor response elicited by the injection of glutamate into the RVLM was potentiated in rats fed the high-salt diet. The glutamate-evoked pressor response was greater in DS rats compared with DR rats, and the response in DS rats was not influenced by the salt content of the diet. These data suggest that tonically active EAA inputs to the RVLM may contribute to salt-sensitive hypertension in the Dahl model.

Key Words: brain stem • glutamic acid • kynurenic acid • hypertension

This article has been cited by other articles:

				M. E. Bardgett, J. J. McCarthy, and S. D. Stocker Glutamatergic Receptor Activation in the Rostral Ventrolateral Medulla Mediates the Sympathoexcitatory Response to Hyperinsulinemia Hypertension, February 1, 2010; 55(2): 284 - 290. [Abstract] [Full Text] [PDF]

				J. M. Adams, M. E. Bardgett, and S. D. Stocker Ventral Lamina Terminalis Mediates Enhanced Cardiovascular Responses of Rostral Ventrolateral Medulla Neurons During Increased Dietary Salt Hypertension, August 1, 2009; 54(2): 308 - 314. [Abstract] [Full Text] [PDF]

				W.-Z. Wang, L. Gao, H.-J. Wang, I. H. Zucker, and W. Wang Tonic Glutamatergic Input in the Rostral Ventrolateral Medulla Is Increased in Rats With Chronic Heart Failure Hypertension, February 1, 2009; 53(2): 370 - 374. [Abstract] [Full Text] [PDF]

				A. F. Sved Tonic glutamatergic drive of RVLM vasomotor neurons? Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2004; 287(6): R1301 - R1303. [Full Text] [PDF]

				J. Horiuchi, S. Killinger, and R. A. L. Dampney Contribution to sympathetic vasomotor tone of tonic glutamatergic inputs to neurons in the RVLM Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2004; 287(6): R1335 - R1343. [Abstract] [Full Text] [PDF]

				V. L. Brooks, K. L. Freeman, and T. L. O'Donaughy Acute and chronic increases in osmolality increase excitatory amino acid drive of the rostral ventrolateral medulla in rats Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2004; 287(6): R1359 - R1368. [Abstract] [Full Text] [PDF]

				V. L. Brooks, K. L. Freeman, and K. A. Clow Excitatory amino acids in rostral ventrolateral medulla support blood pressure during water deprivation in rats Am J Physiol Heart Circ Physiol, May 1, 2004; 286(5): H1642 - H1648. [Abstract] [Full Text] [PDF]

				S. Ito, M. Hiratsuka, K. Komatsu, K. Tsukamoto, K. Kanmatsuse, and A. F. Sved Ventrolateral Medulla AT1 Receptors Support Arterial Pressure in Dahl Salt-Sensitive Rats Hypertension, March 1, 2003; 41(3): 744 - 750. [Abstract] [Full Text] [PDF]