Document Detail

Frequency response characteristics of cerebral blood flow autoregulation in rats.
MedLine Citation:
PMID:  16963612     Owner:  NLM     Status:  MEDLINE    
Transfer function analysis of blood pressure and cerebral blood flow in humans demonstrated that cerebrovascular autoregulation operates most effectively for slow fluctuations in perfusion pressure, not exceeding a frequency of approximately 0.15 Hz. No information on the dynamic properties of cerebrovascular autoregulation is available in rats. Therefore, we tested the hypothesis that cerebrovascular autoregulation in rats is also most effective for slow fluctuations in perfusion pressure below 0.15 Hz. Normotensive Wistar-Kyoto rats (n = 10) were instrumented with catheters in the left common carotid artery and jugular vein and flow probes around the right internal carotid artery. During isoflurane anesthesia, fluctuations in cerebral perfusion pressure were elicited by periodically occluding the abdominal aorta at eight frequencies ranging from 0.008 Hz to 0.5 Hz. The protocol was repeated during inhibition of myogenic vascular function (nifedipine, 0.25 mg/kg body wt iv). Increases in cerebral perfusion pressure elicited initial increases in cerebrovascular conductance and decreases in resistance. At low occlusion frequencies (<0.1 Hz), these initial responses were followed by decreases in conductance and increases in resistance that were abolished by nifedipine. At occlusion frequencies of 0.1 Hz and above, the gains of the transfer functions between pressure and blood flow and between pressure and resistance were equally high in the control and nifedipine trial. At occlusion frequencies below 0.1 Hz, the gains of the transfer functions decreased twice as much under control conditions than during nifedipine application. We conclude that dynamic autoregulation of cerebral blood flow is restricted to very low frequencies (<0.1 Hz) in rats.
Brittany Kolb; Diane L Rotella; Harald M Stauss
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-09-08
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  292     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2007 Jan 
Date Detail:
Created Date:  2007-01-10     Completed Date:  2007-02-20     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H432-8     Citation Subset:  IM    
Dept. of Integrative Physiology, Univ. of Iowa, 410 Field House, Iowa City, IA 52242, USA.
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MeSH Terms
Biological Clocks / physiology*
Blood Flow Velocity / physiology*
Blood Pressure / physiology*
Brain / blood supply*,  physiology*
Cerebrovascular Circulation / physiology*
Computer Simulation
Feedback / physiology
Hemostasis / physiology*
Models, Cardiovascular
Rats, Inbred WKY

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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