Contrasting open-loop dynamic characteristics of sympathetic and vagal systems during baroreflex-mediated heart rate control in rats.
Am J Physiol Regul Integr Comp Physiol
; 317(6): R879-R890, 2019 12 01.
Article
en En
| MEDLINE
| ID: mdl-31618062
ABSTRACT
Although heart rate (HR) is governed by the sympathetic and parasympathetic nervous systems, a head-to-head comparison of the open-loop dynamic characteristics of the total arc from a baroreceptor pressure input to the HR response has yet to be performed. We estimated the transfer function from carotid sinus pressure input to the HR response (HCSPâHR) before and after bilateral vagotomy (n = 7) as well as before and after the administration of a ß-blocker propranolol (n = 8) in anesthetized male Wistar-Kyoto rats. The carotid sinus pressure was perturbed according to a Gaussian white noise signal so that the input power spectra were relatively flat between 0.01 and 1 Hz. The gain plot of HCSPâHR was V-shaped. Vagotomy reduced the dynamic gain at 1 Hz (0.0598 ± 0.0065 to 0.0025 ± 0.0004 beats·min-1·mmHg-1, P < 0.001) but not at 0.01 or 0.1 Hz. ß-Blockade reduced the dynamic gain at 0.01 Hz (0.247 ± 0.069 to 0.077 ± 0.017 beats·min-1·mmHg-1, P = 0.020) but not at 0.1 or 1 Hz. We also estimated the efferent limb transfer function from electrical vagal efferent stimulation to the HR response (HVNâHR) under ß-blockade conditions. We associated the model parameters of HVNâHR with the mean HR and the standard deviation of HR so that HVNâHR could be estimated based only on the HR data. We finally estimated the neural arc transfer function from a pressure input to efferent vagal nerve activity by dividing HCSPâHR by HVNâHR. The mathematically determined vagal neural arc showed derivative characteristics with its phase near zero radians at the lowest frequency.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Sistema Nervioso Simpático
/
Nervio Vago
/
Frecuencia Cardíaca
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Am J Physiol Regul Integr Comp Physiol
Asunto de la revista:
FISIOLOGIA
Año:
2019
Tipo del documento:
Article
País de afiliación:
Japón