Cooling-evoked hemodynamic perturbations facilitate sympathetic activity with subsequent myogenic vascular oscillations via alpha2-adrenergic receptors.
Physiol Res
; 66(3): 449-457, 2017 07 18.
Article
em En
| MEDLINE
| ID: mdl-28248541
ABSTRACT
This study extends our previous work by examining the effects of alpha2-adrenoceptors under cold stimulation involving the increase of myogenic vascular oscillations as increases of very-low-frequency and low-frequency of the blood pressure variability. Forty-eight adult male Sprague-Dawley rats were randomly divided into four groups vehicle; yohimbine; hexamethonium+yohimbine; guanethidine+yohimbine. Systolic blood pressure, heart rate, power spectral analysis of spontaneous blood pressure and heart rate variability and spectral coherence at very-low-frequency (0.02 to 0.2 Hz), low-frequency (0.2 to 0.6 Hz), and high-frequency (0.6 to 3.0 Hz) regions were monitored using telemetry. Key findings are as follows 1) Cooling-induced pressor response was attenuated by yohimbine and further attenuated by hexamethonium+yohimbine and guanethidine+yohimbine, 2) Cooling-induced tachycardia response of yohimbine was attenuated by hexamethonium+yohimbine and guanethidine+yohimbine, 3) Different patterns of power spectrum reaction and coherence value compared hexamethonium+yohimbine and guanethidine+yohimbine to yohimbine alone under cold stimulation. The results suggest that sympathetic activation of the postsynaptic alpha2-adrenoceptors causes vasoconstriction and heightening myogenic vascular oscillations, in turn, may increase blood flow to prevent tissue damage under stressful cooling challenge.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vasoconstrição
/
Pressão Sanguínea
/
Temperatura Baixa
/
Receptores Adrenérgicos alfa 2
/
Frequência Cardíaca
/
Hemodinâmica
Limite:
Animals
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article