Neurogenic modulation of periodic hemodynamics in rabbit skeletal muscle

We characterized the effect of various forms of neural blockade and vasopressin infusion on regular slow-wave flux oscillation (RSWFO). RSWFO, measured with laser-Doppler flowmetry (LDF), was induced by local reduction of arterial pressure in the gastrocnemius muscle of 30 New Zealand White rabbits. At normal median femoral arterial mean pressure, LDF only showed irregular variations. With an intact innervation, RSWFO was maximal at a median femoral mean pressure of 30 mmHg (range 25-53), the median frequency was 1.7 cycles/min (range 1.0-3.0), and the maximum amplitude was 50% (range 19-119). Application of lidocaine to the sciatic nerve, or cutting of this nerve, when arterial pressure was reduced, resulted in disappearance of slow waves in all cases. Intravenous application of guanethidine resulted in a significant reduction of the flux oscillation amplitude from 47 to 10% (P < 0.001). In an additional nine animals with sciatic denervation and local blood pressure reduction, RSWFO could be induced by intravenous vasopressin infusion. These results offer a new pathophysiological concept of periodic hemodynamics as a locally controlled and, with intact innervation, a neurally modulated mechanism for blood flow redistribution in cases of reduced blood pressure and flow.