Proceedings of the High Blood Pressure Research Council of Australia - Modelling the neural control of intrarenal blood flow

1. The aim of the present study was to produce a mathematical model that de scribes the way dynamic changes in renal sympathetic nerve activity affect renal, cortical and medullary blood flow. 2. Cortical blood flow (CBF) and medullary blood flow (MBF) were measured u sing laser-Doppler flowmetry and (total) renal blood flow (RBF) was measure d by transit-time flowmetry in six pentobarbitone-anaesthetized rabbits. Th e renal nerves were stimulated with rectangular pulses of 2 msec width and constant voltage at frequencies of 0.5, 1, 1.5, 2 and 3 Hz. 3. An exponential function with two parameters was applied; steady state ga in and a dynamic constant for the blood flow reduction with stimulation. Th e steady state gain coefficients were similar for RBF and CBF, but signific antly less for MBF. The time taken to reach minimum flow was less for MBF t han for RBF and CBF. 4. The model parameters indicate that there is differential neural control of CBF and MBF.