以α-chloralose麻醉家兔，置於冰盒上使腦溫下降至29℃，然後回升至原有溫度。用銀線雙極電極置於頂葉新皮質記錄腦波，同時也記錄體溫、腦溫(前下視丘區)、呼吸運動、呼吸體積、血液pH、PCO2、PO2。採用人工手技法分析各情況下所記錄的腦波。結果： 1.隨著體溫(腦溫)之下降，4~7 c/s的慢波急劇增加，而相對的8 c/s以上之腦波急劇滅少。心搏、呼吸運動、總通氣量在低溫時均減少，動脈血中PCO2增加，PO2、pH減少；這些變化隨腦溫之回升皆可回復到原狀況。2.過度通氣使血中PCO2減少，pH及PO2增加，使得腦波變成全般性的慢波。3.切斷兩側迷走神經時，呼吸頻率減少，潮氣量增加，但單位時間內之總通氣量不變， pH稍變，腦波亦變化不大。綜合以上事實腦波頻率土之改變與血液pH有密接關係，低體溫所引起腦波頻率之變化，即係呼吸作用引起pH之變化所致。 Rabbits anesthesized with α-chrolalose were examined. The body temperature was lowered down to approximately 29℃ from normal condition by placing the rabbit on the ice box,then their temperature Was restored to normal level again. The EEG pattern was recorded from parietal neocortex with a pairs of silver electrode. The anal temperature, brain (anterior hypothalamus) temperature, frequency of respiratory movement, tidal volume of respiration and the blood characters of pH, PCO2 and PO2 were observed and recorded in each animal simultaneously.
The following results were obtaied:
1)during the course of decreasing of the body temperature, by using the hand-operated analyzing method, the EEG pattern indicated by percentage of fast wave (14-30 c/s) was fouond decreased and modulate EEG (4-7 c/s) increased.
2)under the hyperventilation, blood PCO2 was decreased, pH and PO2 increased. Thus the brain activity could be temporarily reduced, and eventually because of respiratory alkalosis, brain activity tended to go into low state and EEG pattern became flat.
3)by cutting bilateral vagal nerve, respiratory frequency was decreased and tidal volume increased, but total ventilation showed no change. the changes in EEG pattern did not show any significant difference.
All of these changings in EEG pattern were reversible to normal level. Form above observation, we suggest that the EEG pattern was influenced by the variation of the blood pH. These changes can be produced by the body temperature decrease or increase.