Central vagal activation by alpha(2) -adrenergic stimulation is impaired in spontaneously hypertensive rats.
Acta Physiol (Oxf)
; 206(1): 72-9, 2012 Sep.
Article
em En
| MEDLINE
| ID: mdl-22463699
ABSTRACT
AIM:
To elucidate the abnormality of vagal control in spontaneously hypertensive rats (SHR) by measuring left ventricular myocardial interstitial acetylcholine (ACh) release in response to α(2) -adrenergic stimulation as an index of in vivo vagal nerve activity.METHODS:
A cardiac microdialysis technique was applied to the rat left ventricle in vivo, and the effect of α(2) -adrenergic stimulation by medetomidine or electrical vagal nerve stimulation on myocardial interstitial ACh levels was examined in normotensive Wistar-Kyoto rats (WKY) and SHR under anaesthetized conditions.RESULTS:
Intravenous medetomidine (0.1 mg kg(-1) ) significantly increased the ACh levels in WKY (from 2.4 ± 0.6 to 4.2 ± 1.3 nmol L(-1) , P < 0.05, n = 7) but not in SHR (from 2.5 ± 0.7 to 2.7 ± 0.7 nmol L(-1) , n = 7). In contrast, electrical vagal nerve stimulation increased the ACh levels in both WKY (from 1.0 ± 0.4 to 2.9 ± 0.9 nmol L(-1) , P < 0.001, n = 6) and SHR (from 0.9 ± 0.2 to 2.2 ± 0.4 nmol L(-1) , P < 0.001, n = 6). Intravenous administration of medetomidine (0.1 mg kg(-1) ) did not affect the vagal nerve stimulation-induced ACh release in either WKY or SHR.CONCLUSION:
Medetomidine-induced central vagal activation was impaired in SHR, whereas peripheral vagal control of ACh release was preserved. In addition to abnormal sympathetic control, vagal control by the central nervous system may be impaired in SHR.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Nervo Vago
/
Receptores Adrenérgicos alfa 2
/
Medetomidina
Limite:
Animals
Idioma:
En
Revista:
Acta Physiol (Oxf)
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Japão