Tonic excitatory input to the rostral ventrolateral medulla in dahl salt-sensitive rats

Citation
S. Ito et al., Tonic excitatory input to the rostral ventrolateral medulla in dahl salt-sensitive rats, HYPERTENSIO, 37(2), 2001, pp. 687-691
Citations number
15
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Journal title
HYPERTENSION
ISSN journal
0194-911X → ACNP
Volume
37
Issue
2
Year of publication
2001
Part
2
Supplement
S
Pages
687 - 691
Database
ISI
SICI code
0194-911X(200102)37:2<687:TEITTR>2.0.ZU;2-W
Abstract
The goal of the present study was to test the hypothesis that the balance o f tonic excitation and inhibition of vasomotor neurons in the rostral ventr olateral medulla (RVLM) driven by excitatory amino acid (EAA)-mediated inpu ts to the RVLM is shifted toward excitation in Dahl salt-sensitive (DS) rat s compared with Dahl salt-resistant (DR) rats. Glutamate and the EAA antago nist kynurenic acid were microinjected into the RVLM of chloralose-anesthet ized 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 differ ence was greatly exaggerated by high dietary salt intake. Bilateral injecti on of kynurenic acid (2.7 nmol) into the RVLM decreased mean arterial press ure by 16 +/-2 mm HE in DS rats fed a diet containing 0.3% NaCl, and this e ffect was significantly larger in DS rats fed the high-salt diet (40 +/-2 m m Hg). In contrast, injections of kynurenic acid into the RVLM did not sign ificantly decrease arterial pressure in DR rats fed either diet. In DR rats , the presser response elicited by the injection of glutamate into the RVLM was potentiated in rats fed the high-salt diet. The glutamate-evoked press er 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 s uggest that tonically active EAA inputs to the RVLM may contribute to salt- sensitive hypertension in the Dahl model.