抄録
This study investigated the relation between the mechanisms controlling heart rate and respiratory movement in carp. An electrocardiogram (ECG) and electromyogram (EMG) of the lower jaw for detection of the respiratory movements (mouth and opercular movements) were recorded simultaneously by the radiotelemetry system (DSI, USA). Adult carp were reared in individual tanks under a 12h/12h light-dark cycle, and the water temperature was kept at 25°C. In carp, both the heart rate (HR) and respiratory rate (RR) were irregular compared to the HR and RR in mammals. The HR was usually within a range of about 40 to 120 /min and the HR was greater or less than the RR. In some cases, both were equal, and both parameters were almost synchronized. When 2 or 3 respiratory movements grouped and were followed by pauses of respiratory movement, the R-R intervals of the ECG during the grouping respiratory movements were shorter than those during the pauses. The carp were stressed by tapping on the tank wall or by switching off the room light. These stresses transiently decreased both the HR and RR. After intraperitoneal administration of atropine sulfate (1mg/kg), the HR increased and became regular, and stress responses of the HR disappeared. These results suggest that the mechanisms controlling the heart rate and respiratory movement were closely related. And the vagal nerve plays a major role in controlling the HR mechanism in carp. [Jpn J Physiol 54 Suppl:S206 (2004)]
