家兎脊髄血流量の測定—胸髄中心灰白質血流量と炭酸ガス反応性

MEASUREMENT OF SPINAL CORD BLOOD FLOW IN RABBITS : CENTRAL GRAY MATTER FLOW AND CO2 REACTIVITY

I．はじめに

　脊髄の血流量を定量的に測定する試みは，1955年Landauら^15）によるRIを使用した測定報告以後，種々の方法による報告^{2〜15,17〜19,21）}がみられるが，定量的に同一個体で繰返し測定することは，なかなか困難であつた。

　1964年Auklandら^1）により報告された水素クリアランス法は，白金電極を臓器に刺入し，水素のクリアランスカーブより血流量を測定する方法で，臓器に対し傷害を与えるという欠点はあるにせよ，脊髄のような，深部に位置した小さな，又，血管構築も複雑な臓器においては，非常な有用な方法である。

Spinal cord blood flow (SCBF) was measured in 20 rabbits anesthetized with sodium pentobarbital. The platinum electrodes (0.3 mm in diameter) were inserted into the central gray matter of the thoracic spinal cord (Th8-10). In all animals, blood pressure and pAO₂ remained constantly in the normal range. The pACO₂ was changed by ven-tilation. Blood gases were checked both before and after each spinal cord blood flow measurement.

The results are as follows.

1. Seventy-three percent of the clearances re-corded from the gray matter were monoexponential and in the white matter almost all were mono-exponential.

2. The mean values of gray matter SCBF of all animals was 38.3±1.85ml/100g/min (SE) at normo-capnea and the white matter was 19.5±1.33ml/ 100g/min.

3. An almost linear relationship exists between the pACO₂ and SCBF. The values were 0.62 ml/ 100g/min/torr in the gray matter and 0.38 ml/100g/ min/torr in the white matter.