One-and two-dimensional continuation techniques are applied to study the bifurcation structure of a model of renal flow and pressure control. Integrating the main physiological mechanisms by which the individual nephron regulates the incoming blood flow, the model describes the interaction between the tubuloglomerular feedback and the response of the afferent arteriole. It is shown how a Hopf bifurcation leads the system to perform self-sustained oscillations if the feedback gain becomes sufficiently strong, and how a further increase of this parameter produces a folded structure of overlapping period-doubling cascades. Similar phenomena arise in response to increasing blood pressure. The numerical analyses are supported by existing experimental results on anesthetized rats. © 1996 American Institute of Physics. ͓S1054-1500͑96͒02503-7͔The function of the kidneys plays an essential role for the regulation of the blood pressure and hence for the development of cardiovascular diseases. At the same time, the kidneys dispose of a variety of mechanisms to protect their own function against variations in the blood pressure. Experiments on rats have shown that these mechanisms can lead to self-sustained oscillations, period doublings and chaos. Based on a detailed physiological knowledge we have developed a model that can reproduce these findings. A two-parameter bifurcation analysis of the model shows a so-called crossroad structure of overlying period-doubling bifurcations previously observed for one-and two-dimensional mappings.

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