AJP - Renal Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
 QUICK SEARCH:   [advanced]


     


Am J Physiol Renal Physiol (May 6, 2009). doi:10.1152/ajprenal.00114.2009
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
297/1/F155    most recent
00114.2009v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Siu, K. L
Right arrow Articles by Chon, K. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Siu, K. L
Right arrow Articles by Chon, K. H.
Submitted on February 26, 2009
Revised on April 18, 2009
Accepted on May 3, 2009

Detection of low frequency oscillations in renal blood flow

Kin L Siu, Biin Sung, William A Cupples1, Leon Moore2, and Ki H. Chon3*

1 University of Victoria
2 SUNY Stony Brook
3 SUNY - Stony Brook

* To whom correspondence should be addressed. E-mail: ki.chon{at}sunysb.edu.

Detection of the low frequency (LF; ~0.01 Hz) component of renal blood flow, which is theorized to reflect the action of a third renal autoregulatory mechanism, has been difficult due to its slow dynamics. In this work, we used three different experimental approaches to detect the presence of the LF component of renal autoregulation using normotensive and spontaneously hypertensive rats (SHR), both anesthetized and unanesthetized. The first experimental approach utilized a blood pressure forcing in the form of a chirp, an oscillating perturbation with linearly increasing frequency, to elicit responses from the LF autoregulatory component in anesthetized normotensive rats. The second experimental approach involved collection and analysis of spontaneous blood flow fluctuation data from anesthetized normotensive rats and SHR to search for evidence of the LF component in the form of either amplitude or frequency modulation of the myogenic and tubuloglomerular feedback mechanisms. The third experiment used telemetric recordings of arterial pressure and renal blood flow from normotensive rats and SHR for the same purpose. Our transfer function analysis of chirp signal data yielded a resonant peak centered at 0.01 Hz that is greater than 0 dB, with the transfer function gain attenuated to lower than 0 dB at lower frequencies, which is a hallmark of autoregulation. Analysis of the data from the second experiments detected the presence of ~0.01 Hz oscillations only with isoflurane albeit the strength was weaker when compared to telemetry recordings. With the third experimental approach, the strength of the LF component was significantly weaker in the SHR. In summary, our detection via the AM approach of interactions between the LF component and both TGF and MYO, with the LF component having an identical frequency to that of the resonant gain peak, provides evidence that 0.01 Hz oscillations may represent the third autoregulatory mechanism.







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 1977 by the American Physiological Society.