Regional spinal cord blood flow during local cooling.

We used the tissue distribution of [14C]butanol to quantitate regional blood flow in the spinal cord (RSCBF) of pentobarbital-anesthetized, normothermic rats in which segmental local cooling pentobarbital-anesthetized, normothermic rats in which segmental local cooling of the spinal cord (to 25-28 degrees C) at vertebral levels C4-C6 (n = 6) or T13-L1 (n = 6) was induced. Thirty minutes later, blood flow measurements were made at seven levels of the spinal cord and in the sciatic nerve trunks and biceps femoris muscles. Sham-cooled rats served as controls (n = 12). In control rats, RSCBF varied between 41.5 +/- 2.4 and 65.1 +/- 3.2 ml.min-1.100 g-1. Local cooling of the C4-C6 cord segment reduced RSCBF by 32%, from 65.1 +/- 3.2 to 44.4 +/- 3.5 ml.min-1.100 g-1 (P less than 0.01). Tissue vascular resistance (R) in the cooled C4-C6 segment was elevated versus control. There were no other changes in RSCBF at the other cord levels or in the cauda equina. Similarly, local cooling of the T13-L1 segment resulted in a 40% fall in RSCBF in that segment, from 57.1 +/- 2.4 to 34.1 +/- 4.3 ml.min-1.100 g-1 (P less than 0.001). R in the cooled T13-L1 segment was elevated versus control. RSCBF was reduced by 30% in the adjacent proximal T12 segment (P less than 0.001) and by 21% in the adjacent distal L2-L3 segment (P less than 0.05). R was increased in both of these adjacent segments. RSCBF was not altered elsewhere in the cord.(ABSTRACT TRUNCATED AT 250 WORDS)