Regional sciatic nerve and muscle blood flow in conscious and anesthetized rats

The regulation of peripheral nerve blood flow is incompletely understood. Regional blood flow in the rat sciatic nerve (NBF) and hamstring muscle (MBF) was measured in both conscious and anesthetized normal rats and in rats that had undergone surgical exposure of one sciatic nerve just prior to measurement. The distribution of [14C]butanol following its bolus intravenous injection was used to determine the flows in a modification of the "indicator fractionation" technique. NBF in normal rats was similar in limb pairs and was unaffected by pentobarbital sodium anesthesia. The pooled value was 12.5 +/- 1.1 ml X min-1 X 100 g-1. NBF was unaffected by sham operation in the conscious rats but was doubled in operated limbs of anesthetized rats (P less than 0.001). MBF in conscious normal rats was five times that measured during anesthesia. As in NBF, sham operation significantly increased MBF only in anesthetized rats (P less than 0.01). [14C]butanol distribution is a sensitive indicator of NBF and MBF. Mere surgical exposure of the nerve significantly increases NBF and MBF in anesthetized, but not in conscious rats.