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Characteristics of efferent discharge activity in cardiac vagal nerve of the rabbit

Zhang Pingcai, Chang Yingtbai

Department of Physiology, Beijing Second Medical College. Beijing, China

Abstract

Three types of discharge pattern were recorded from the cardiac vagal efferent nerve of the rabbit immobilized with flaxedil. 1 .Rhythmic discharges synchronized with the efferent impulses of the phrenic nerve. Two phases were distinguished during each discharge period: the first phase was roughly simultaneous with the phrenic efferent flow, and the second one developed during the later period of the phrenic efferent discharges or immediately after the end of the phrenic discharge. 2. Continuous discharges. 3. Occasional discharges with high amplitude and frequency. The phrenic efferent discharges were obviously depressed whenever the burst appeared. An increase in the activity of the cardiac branch of the vagus could be induced by release of the occluded common carotid arteries. An enhanced discharge in the cardiac vagus and a decreased heart rate could be induced by asphysia and intravenous injection of adrenaline. On the other hand, the vagal discharges could be depressed and the heart rate increased by inflation of the lungs, hyperventilation and amyl nitrite inhalation.

Key words: Cardiac vagus efferent;Discharges;Heart rate

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Citing This Article：

Zhang Pingcai, Chang Yingtbai. Characteristics of efferent discharge activity in cardiac vagal nerve of the rabbit. Acta Physiol Sin 1985; 37 (1): (in Chinese with English abstract).