BIFURCATION-ANALYSIS OF NEPHRON PRESSURE AND FLOW REGULATION

One- and two-dimensional continuation techniques are applied to study the bifurcation structure of a model of renal flow and pressure contro l. Integrating the main physiological mechanisms by which the individu al 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 s ystem to perform self-sustained oscillations if the feedback gain beco mes sufficiently strong, and how a further increase of this parameter produces a folded structure of overlapping period-doubling cascades. S imilar phenomena arise in response to increasing blood pressure. The n umerical analyses are supported by existing experimental results on an esthetized rats. (C) 1996 American Institute of Physics.