Analysis of nonstationarity in renal autoregulation mechanisms using time-varying transfer and coherence functions
| Autor: | Niels-Henrik Holstein-Rathlou, William A. Cupples, Leon C. Moore, Ki H. Chon, Yuru Zhong |
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| Rok vydání: | 2008 |
| Předmět: |
Male
medicine.medical_specialty Hypertension Renal Physiology Kidney Glomerulus Statistical difference Hemodynamics Myogenic mechanism Blood Pressure Models Biological Rats sprague dawley Renal Circulation Rats Sprague-Dawley Rats Inbred SHR Physiology (medical) Internal medicine medicine Hemodynamics and Cardiorenal Integration Animals Homeostasis Autoregulation Tubuloglomerular feedback Mathematics Feedback Physiological Coherence (statistics) Rats Kidney Tubules Endocrinology Cardiology Kidney tubules |
| Zdroj: | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 295:R821-R828 |
| ISSN: | 1522-1490 0363-6119 |
| Popis: | The extent to which renal blood flow dynamics vary in time and whether such variation contributes substantively to dynamic complexity have emerged as important questions. Data from Sprague-Dawley rats (SDR) and spontaneously hypertensive rats (SHR) were analyzed by time-varying transfer functions (TVTF) and time-varying coherence functions (TVCF). Both TVTF and TVCF allow quantification of nonstationarity in the frequency ranges associated with the autoregulatory mechanisms. TVTF analysis shows that autoregulatory gain in SDR and SHR varies in time and that SHR exhibit significantly more nonstationarity than SDR. TVTF gain in the frequency range associated with the myogenic mechanism was significantly higher in SDR than in SHR, but no statistical difference was found with tubuloglomerular (TGF) gain. Furthermore, TVCF analysis revealed that the coherence in both strains is significantly nonstationary and that low-frequency coherence was negatively correlated with autoregulatory gain. TVCF in the frequency range from 0.1 to 0.3 Hz was significantly higher in SDR (7 out of 7, >0.5) than in SHR (5 out of 6 |
| Databáze: | OpenAIRE |
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