Autonomic control of the diurnal variation in arterial blood pressure and heart rate in spontaneously hypertensive and Wistar–Kyoto rats
作者:
Peter Friberg,
Birgitha Karlsson,
Margareta Nordlander,
期刊:
Journal of Hypertension
(OVID Available online 1989)
卷期:
Volume 7,
issue 10
页码: 799-807
ISSN:0263-6352
年代: 1989
出版商: OVID
关键词: Spontaneously hypertensive rats;blood pressure variability;heart rate variability;diurnal rhythm;autonomic control
数据来源: OVID
摘要:
The relative influences of sympathetic and parasympathetic neural modulation on mean arterial pressure (MAP) and heart rate (HR), and their respective variabilities, were studied in young spontaneously hypertensive rats (SHR) and Wistar–Kyoto rats (WKY). An on-line computerized system was used for continuous intra-arterial measurements of MAP and HR in unrestrained rats. In addition, the autonomic nervous control of MAP and HR was studied in ageing SHR and WKY. Both WKY and SHR showed diurnal rhythms with regard to MAP and HR. The MAP variability was higher in SHR than in WKY during both daytime (inactive) and night-time (active), and did not change in response to either β1-adrenoceptor- or cholinergic blockade. Structural vascular changes, with a resultant increase in reactivity, may explain the elevated MAP variability in SHR. HR variability was clearly reduced in SHR; this was not influenced by vagal blockade, whereas HR variability was significantly reduced in WKY. This pattern is suggested to be due to a reduced tonic vagal discharge in SHR, as part of a persistent, mild defence reaction. The initial reduction in vagal activity will in turn eliminate vagally mediated tachycardias. Furthermore, administration of β1-blockade to SHR of different ages caused a greater fall in MAP and HR than in WKY, indicating an increased dependence upon the sympathetic nervous system in SHR with age.
点击下载:
PDF
(734KB)
返 回