THE FUNCTIONAL-SIGNIFICANCE OF THE 10-HZ SYMPATHETIC RHYTHM - A HYPOTHESIS

This paper reviews work from our laboratory on the 10-Hz rhythm in sym pathetic nerve discharge of the cat and offers a hypothesis on its fun ctional significance. The rhythm is ubiquitous to the discharges of sy mpathetic nerves with different cardiovascular targets and arises from a system of coupled nonlinear brain stem oscillators, each of which h as a selective relationship with a different portion of the spinal sym pathetic outflow. The 10-Hz rhythmic discharges of sets of sympathetic nerves are differentially related and the pattern of relationships in one experiment can be the reverse of that in the next. We hypothesize that nonuniform and dynamic coupling of the central circuits controll ing different sympathetic nerves is the basis for the formulation of c omplex cardiovascular response patterns that include differential chan ges in regional blood flows.