ウナギ心電図の水中電極による導出
1971 年 37 巻 2 号 p. 94-97
詳細
1971 年 37 巻 2 号 p. 94-97
In the eel, Anguilla japonica, which has a heart with a strong electromotive force, the ECGs were found to be recordable by electrodes placed in the water apart from fish's body. An apparatus so devised that an “underwater electrode” was attached to either end of a plastic cylinder was submerged on the bottom of an aquarium. When the fish slipped into the cylinder, ECGs were easily recorded, being superimposed upon slow undulation of the base line caused by the respiratory movement of the fish. QRS complex of the ECG was marked, while P and T waves were identified with difficulty. The amplitude of QRS complex was about 0.5 mV.
This method enabled us to observe the heart rate of the eel under least dis-turbed state. Ordinary heart rate was not quite regular. Very slight stimulation was enough to bring about cardiac inhibition, which was also accompanied by a considerable reduction in the amplitude of the QRS. After rough treatment, such as deep anaesthesia or exposure to air, the heart rate showed remarkable compensa-tory increase, reaching a value a few times higher than the normal level. In the American eel, A. rostrata, QRS was about 0.02 mV. This indicates that the electro-motive force of the heart in this species is much smaller than in A. japonica.
