静脈内に投与したATPのヒト脳血流量に対する作用

EFFECT OF INTRAVENOUS ADENOSINE-5% TRIPHOSPHATE (ATP) ON CEREBRAL BLOOD FLOW IN AWAKE MAN

I．はじめに

　adenosine-5’-triphosphate，disodium sait （以下ATP）の脳血流量（CBF）に対する作用に関して，動物種の違い・薬物の投与方法・血流量の測定方法などの差によつて，異なつた結果が報告されており，いまだ一定の見解が得られていない。

　CBFに最も大きな影響を与えている生理的因子は動脈血の炭酸ガス分圧（PaCO₂）であり，CBFの研究にあたつては，PaCO₂を常に考慮に入れなければならない。ある薬物の投与によつてPaCO₂が変化した場合には，PaCO₂によるCBFへの影響を補正した上でなければ，薬物自体のCBFに対する作用に言及することはできない。一般の治療薬の効果を確かめるためには，動脈内投与よりは，静脈内投与の作用を知る必要がある。クリアランス法によつて得られた血流は，物質交換にあずかる有効血流量を，より正確に表わすものと考えられる。以上の理由から，われわれは，対照時・7％CO₂吸入中・ATPの持続的静脈内注入中に，¹³³Xe ciearance methodを用いてCBFを測定したので報告する。

Seven patients had angiography as a part of theirroutine clinical examination. Except for local an-esthesia for intracarotid catheterization, neitherpremedication nor general anesthesia was applied. Inno patient was any persistent neurological deficits orabnormalities of the cerebral vessele evident, otherthan mild arteriosclerosis. Cerebral blood flow(CBF) was measured by an intracarotid ¹³³Xe clear-ance method on five stages at intervals of 15-20minutes. The stages were composed of control(untreated), 7%CO₂ inhalation, ATP infusion,control (regained), and ATP infusion. Arterialblood was sampled from the catheter immediatelybefore each ¹³³Xe injection and analyzed for PaCO₂.ATP concentration was measured with an "ATPUV-Test" (Boehringer Manheim GmbH) in wholearterial blood obtained before and 3-7min after theconstant intravenous infusion of ATP (0.3-30.0μmo-les/min; mean value 6.5), when CBF was measured.Two patients had some discomfort during ATP in-fusion. One complained of nausea, and the otherhad a sensation of heat in the body. Control CBFwas in the range of 35.9-52.6ml/100g/min, whichwas compatible with our previous report¹⁾. DuringATP infusion, ATP concentration of arterial bloodincreased on 5 occasions (with maximum increaseof 470nmoles/ml), remained unchanged on 3 occa-sions and decreased on 3 occasions (maximum de-crease of 70nmoles/ml). Correlation between CBFand PaCO₂ of these patients was paralleled thatseen in normal cases¹⁾, despite changes in arterialATP concentrations. Intravenous ATP in as highdoses as 30μmoles/min had little effect on thecerebral vessels in awake man with normal CBF.