抄録
Regional spinal cord blood flow (rSCBF) in gray matter and its response to CO2 inhalation were estimated in awake rats at three spinal levels by the hydrogen clearance method and 14C-antipyrine autoradiography. Regional blood flow levels obtained by two methods were well correlated. The gray matter rSCBF values of T-11, T-13 and L-2 levels measured by the hydrogen clearance method were 35.9±3.2, 45.0±3.5 and 46.0±5.2 ml/min/100 g, respectively, and those measured by 14C-antipyrine autoradiography were between 42.2 and 51.3 ml/min/ 100 g. The rSCBF values in the thoracic gray matter were somewhat lower than those in the lumbar enlargement. The differences of rSCBF values with respect to the spinal levels were small in the white matter (20.7-22.9 ml/min/ 100 g). By CO2 gas inhalation the rSCBF increased linearly in proportion to PaCO2 increase as long as PaCO2 was below 80-90 mmHg. The effect of CO2 inhalation on rSCBF was expressed as “percent increase over basal flow against PaCO2 increase” [ΔrSCBF/ΔPaCO2/rSCBF(PaCO2=35 mmHg)×100], and the values of T-11, T-13 and L-2 levels were 6.9±0.9, 4.9±1.1 and 7.0±0.4 %/mmHg, respectively.
