脳定常電位（SP）の測定—動物脳のSPの大きさの測定と脳死判定への応用

STUDY OF STATIONARY POTENTIAL (SP), 2ND REPORT: ITS VALUES IN VARIOUS ANIMALS AND ITS APPLICATION FOR ESTIMATION OF BRAIN DEATH

　1）脳に陽性の一定の電位（脳定常電位，StationaryPotential略してSP）が存在することを，いろいろの手法で証明した。そのSPの大きさは，ラッテで7.6±2.4mV．ウサギ9.8±2.4mV，ネコ10.2±1.8mV，イヌ10.9±2.2mVと推定した。

　2）ヒトのSPは臨床的観察から約20mVと推定した。

　3）SPの測定で，脳死の判定・脳の予後の推測がある程度可能なことを，その理論的根拠と共に示した。すなわち，SPは普通は恒常的に陽性であるが，neuronの傷害きたすような状況下（例えばanoxiaとか低血糖）では，その程度に応じて降下し，脳死ではSPが0あるいはやや（−）ということにより推定できる。

We have been studying since 1961 the electrical phenomena concerning "Stationary Potential (SP)", which is to be compared to "water level" of the brain. We reported in former articles that bymeasuring the SP on the scalp, intracranial organic diseases could be diagnosed.

We studied with new experimental procedures (1) to verify the SP (2) to measure the voltage of the SP (3) to apply it for the judgement of brain death.

Ninety eight animals (Forty dogs, thirty cats, twelve rats, five rabbits, one maccaca monky and nine non-mammalian vertebrates) were used for this experiments.

The principle of the measurement of the SP values is shown in Fig. 1. The indifferent elect-rode was attached in animals usually on the tongue, in case of human being, on the tip of the nose. Several methods of measurement were used in each species of animals and the value of SP were illus-srated in Fig. 4, 5 and 6. In case of man, themagnitude of the SP was estimated about plus 20 mV (either on the scalp or on the cortex) from clinical observations.

The SP is to be corelated to the neuronal mem-brane potential and/or metabolic function of the brain, so it might be the reflexion of integral activity of the neurons. In case of brain death, the SP (that is estimated from the potential be-tween the vertex to the nose) generally decreased to zero, and in case of anoxia, hypoglycemia or other neuronal damage it decreased in certain ex-tent according to the degree of damage.

The above-mentioned experiments and obser-vations indicate that by measureing the SP on the scalp, one could estimate the brain death, or the grade of cerebral damage.