In the Squilla heart ganglion, the pacemaker is located in the rostral group of cells. After spontaneous firing ceased, the electrophysiological properties of these cells were examined with intracellular electrodes. Cells respond to electrical stimuli with all-or-none action potentials. Direct stimulation by strong currents decreases the size of action potentials. Comparison with action potentials caused by axonal stimulation and analysis of time relations indicate that with stronger currents the soma membrane is directly stimulated whereas with weaker currents the impulse first arises in the axon and then invades the soma. Spikes evoked in a neuron spread into all other neurons. Adjacent cells are interconnected by electrotonic connections. Histologically axons are tied with the side-junction. B spikes of adjacent cells are blocked simultaneously by hyperpolarization or by repetitive stimulation. Experiments show that under such circumstances the B spike is not directly elicited from the A spike but is evoked by invasion of an impulse or electrotonic potential from adjacent cells. On rostral stimulation a small prepotential precedes the main spike. It is interpreted as an action potential from dendrites.
Article|
March 01 1967
Electrical Properties of the Pacemaker Neurons in the Heart Ganglion of a Stomatopod, Squilla oratoria
Akira Watanabe,
Akira Watanabe
From the Department of Physiology, Tokyo Medical and Dental University, Yushima, Bunkyo-Ku, Tokyo, Japan.
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Shosaku Obara,
Shosaku Obara
From the Department of Physiology, Tokyo Medical and Dental University, Yushima, Bunkyo-Ku, Tokyo, Japan.
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Toyohiro Akiyama,
Toyohiro Akiyama
From the Department of Physiology, Tokyo Medical and Dental University, Yushima, Bunkyo-Ku, Tokyo, Japan.
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Katsuto Yumoto
Katsuto Yumoto
From the Department of Physiology, Tokyo Medical and Dental University, Yushima, Bunkyo-Ku, Tokyo, Japan.
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Akira Watanabe
From the Department of Physiology, Tokyo Medical and Dental University, Yushima, Bunkyo-Ku, Tokyo, Japan.
Shosaku Obara
From the Department of Physiology, Tokyo Medical and Dental University, Yushima, Bunkyo-Ku, Tokyo, Japan.
Toyohiro Akiyama
From the Department of Physiology, Tokyo Medical and Dental University, Yushima, Bunkyo-Ku, Tokyo, Japan.
Katsuto Yumoto
From the Department of Physiology, Tokyo Medical and Dental University, Yushima, Bunkyo-Ku, Tokyo, Japan.
Dr. Obara's present address is the Laboratory of Neurophysiology, Department of Neurology, College of Physicians and Surgeons, Columbia University, New York
Received:
March 30 1966
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright © 1965 by The Rockefeller Institute Press
1967
J Gen Physiol (1967) 50 (4): 813–838.
Article history
Received:
March 30 1966
Citation
Akira Watanabe, Shosaku Obara, Toyohiro Akiyama, Katsuto Yumoto; Electrical Properties of the Pacemaker Neurons in the Heart Ganglion of a Stomatopod, Squilla oratoria . J Gen Physiol 1 March 1967; 50 (4): 813–838. doi: https://doi.org/10.1085/jgp.50.4.813
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