BLOOD-FLOW AND AUTOREGULATION IN SOMATIC AND AUTONOMIC GANGLIA - COMPARISON WITH SCIATIC-NERVE

We studied blood pow rates along the sciatic nerve and in the superior cervical and L-5 dorsal root ganglia of mrs at rest and during reduct ions and increases in mean arterial pressure induced by partial exsang uination or blood transfusion. Blood flow was measured by the tissue d istribution of [C-14]iodoantipyrine and autoradiography. At rest, bloo d pow did not vary along the peripheral nerve, but was two to three ti mes greater in dorsal root and superior cervical ganglia. In periphera l nerve, blood flow increased with increases in blood pressure. In con trast, blood flow in dorsal root and sympathetic ganglia did not vary with changes in pressure. Thus, peripheral nerve cell bodies have grea ter blood flow than their axons; ganglion blood flow is autoregulated within the range of blood pressure tested. Nerve ganglia appear to be protected against ischaemic stress by autoregulation rather than by a blood flow 'safety margin', as in peripheral nerve.