Diazepam-sensitive GABA(A) receptors in the NTS participate in cardiovascular control.
Brain Res
; 773(1-2): 53-60, 1997 Oct 31.
Article
en En
| MEDLINE
| ID: mdl-9409704
ABSTRACT
The present study employed neuropharmacological and receptor binding protocols to determine if diazepam-sensitive (DS) gamma-aminobutyric acid-A (GABA(A)) receptors in the nucleus tractus solitarius (NTS) participate in autonomic regulation of cardiovascular function. The first set of protocols was designed to determine if GABA(A) receptors in the NTS were functionally modulated by the benzodiazepine agonist, diazepam. Mean arterial pressure and heart rate responses to microinjection of GABAergic substances into the NTS were examined in urethane-anesthetized rats. Microinjection of the GABA(A) agonist isoguvacine into the NTS increased mean arterial pressure and heart rate, and these effects were blocked by the GABA(A) receptor antagonist, bicuculline. Preadministration of diazepam into the NTS potentiated the pressor actions of isoguvacine and had variable effects on heart rate changes. Flumazenil, a benzodiazepine antagonist, blocked the diazepam-induced potentiation of the pressor response to isoguvacine. The second protocol employed receptor autoradiography to examine the presence of DS and diazepam-insensitive (DI) GABA(A) receptors in the NTS. Autoradiography confirmed that DS GABA(A) receptors were present in the NTS; however, no measurable levels of DI GABA(A) receptors were detected. We conclude that GABA(A)-mediated integration of central autonomic control in the NTS is mediated solely by DS GABA(A) receptors.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Presión Sanguínea
/
Encéfalo
/
Núcleo Solitario
/
Receptores de GABA-A
/
Diazepam
/
Frecuencia Cardíaca
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
Brain Res
Año:
1997
Tipo del documento:
Article
País de afiliación:
Estados Unidos