Autoregulation and non-homeostatic behaviour of renal blood flow in conscious dogs.
1. Spontaneously occurring haemodynamic variations within 4 h affecting renal blood flow (RBF) were compared with externally induced short changes of renal artery pressure (RAP) in conscious resting dogs. 2. In all animals in which RAP was servo-controlled (n = 6), perfect autoregulation of RBF was...
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| Main Authors: | , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
01 March 1993
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| In: |
The journal of physiology
Year: 1993, Volume: 462, Issue: 1, Pages: 261-273 |
| ISSN: | 1469-7793 |
| DOI: | 10.1113/jphysiol.1993.sp019554 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1113/jphysiol.1993.sp019554 Verlag, lizenzpflichtig, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1113/jphysiol.1993.sp019554 
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| Author Notes: | P. B. Persson, H. Ehmke, H. R. Kirchheim, B. Janssen, J. E. Baumann, A. Just, B. Nafz |
| Summary: | 1. Spontaneously occurring haemodynamic variations within 4 h affecting renal blood flow (RBF) were compared with externally induced short changes of renal artery pressure (RAP) in conscious resting dogs. 2. In all animals in which RAP was servo-controlled (n = 6), perfect autoregulation of RBF was observed. 3. In all 4 h recordings of spontaneous renal blood flow (n = 9), certain combinations of blood pressure and blood flow occurred remarkably frequently as indicated by three-dimensional frequency distributions. 4. Cluster analysis demonstrated significant differences between these areas of accumulation (P < 0.001). The average number of 'set points' per 4 h session was 3.1 +/- 0.3. 5. The shift from one set point to another is probably mediated by multiple control systems impinging on renal haemodynamics as suggested by 1/f fluctuations. 6. In seven dogs, an additional renal venous catheter allowed measurements of the arterial-venous (A-V) oxygen partial pressure (PO2) difference as an indicator of the renal metabolic demand. An inverse relationship between A-V PO2 difference and RBF (Y = X(-0.034) + 40.9, r = -0.9, P < 0.001) was found, indicating that the metabolic demands vary little (if at all) between the different set points. 7. The presented data suggest a modified view of renal homeostasis. There exist distinct combinations between RBF and RAP, which are very stable. Autoregulation merely buffers the fluctuations around these set points. |
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| Item Description: | Gesehen am 04.12.2024 |
| Physical Description: | Online Resource |
| ISSN: | 1469-7793 |
| DOI: | 10.1113/jphysiol.1993.sp019554 |