Theoretical simulation of the calcium action potential in squid giant synapse: Repetitive stimulation

1993 ◽  
Vol 19 (1) ◽  
pp. 71-84
Author(s):  
Arunava Adhikari ◽  
Kamales Bhaumik
Keyword(s):  
Action Potential ◽  
Repetitive Stimulation ◽  
Theoretical Simulation ◽  
Squid Giant Synapse ◽  
Giant Synapse ◽  
Calcium Action Potential

The effect of repetitive stimulation on the passive electrical properties of the presynaptic terminal of the squid giant synapse

1979 ◽  
Vol 206 (1164) ◽  
pp. 293-306 ◽  
Keyword(s):  
Electrical Properties ◽  
Transmitter Release ◽  
Sea Water ◽  
Presynaptic Terminal ◽  
Repetitive Stimulation ◽  
Constant Current ◽  
Current Pulses ◽  
Squid Giant Synapse ◽  
Giant Synapse ◽  
Passive Electrical Properties

The resting electrical properties of the presynaptic terminal of the squid giant synapse have been determined by using constant current pulses. After short periods of repetitive stimulation, the terminal resistance, time constant and capacitance are found to be increased. These changes are absent in terminals bathed in artificial sea water containing no calcium, and sea water containing 5 mM cobalt. It seems likely that these changes are associated with transmitter release.

Action potential propagation through embryonic dorsal root ganglion cells in culture. II. Decrease of conduction reliability during repetitive stimulation

1994 ◽  
Vol 72 (2) ◽  
pp. 634-643 ◽  
Author(s):  
C. Luscher ◽  
J. Streit ◽  
P. Lipp ◽  
H. R. Luscher
Keyword(s):  
Dorsal Root Ganglion ◽  
Action Potential ◽  
Intracellular Calcium ◽  
Dorsal Root ◽  
Channel Blocker ◽  
Extracellular Calcium ◽  
Repetitive Stimulation ◽  
Calcium Currents ◽  
Double Pulse ◽  
Extracellular Potassium

1. The reliability of the propagation of action potentials (AP) through dorsal root ganglion (DRG) cells in embryonic slice cultures was investigated during repetitive stimulation at 1–20 Hz. Membrane potentials of DRG cells were recorded intracellularly while the axons were stimulated by an extracellular electrode. 2. In analogy to the double-pulse experiments reported previously, either one or two types of propagation failures were recorded during repetitive stimulation, depending on the cell morphology. In contrast to the double-pulse experiments, the failures appeared at longer interpulse intervals and usually only after several tens of stimuli with reliable propagation. 3. In the period with reliable propagation before the failures, a decrease in the conduction velocity and in the amplitude of the afterhyperpolarization (AHP), an increase in the total membrane conductance, and the disappearance of the action potential “shoulder” were observed. 4. The reliability of conduction during repetitive stimulation was improved by lowering the extracellular calcium concentration or by replacing the extracellular calcium by strontium. The reliability of conduction decreased by the application of cadmium, a calcium channel blocker, 4-amino pyridine, a fast potassium channel blocker, or apamin or muscarine, the blockers of calcium-dependent potassium channels. The reliability of conduction was not effected by blocking the sodium potassium pump with ouabain or by replacing extracellular sodium with lithium. 5. In the period with reliable propagation cadmium, apamin, and muscarine reduced the amplitude of the AHP. The shoulder of the action potential was more pronounced and not sensitive to repetitive stimulation when extracellular calcium was replaced by strontium. It disappeared when cadmium was applied. 6. In DRG somata changes of the intracellular Ca2+ concentration were monitored by measuring the fluorescence of the Ca2+ indicator Fluo-3 with a laser-scanning confocal microscope. During repetitive stimulation, an accumulation of intracellular calcium occurred that recovered very slowly (tens of seconds) after the AP trains. 7. Computer model simulations performed in analogy to the experimental protocols produced conduction failures during repetitive stimulation only when the calcium currents during the APs were reduced. 8. From these findings it is concluded that conduction failures during repetitive stimulation are dependent on an accumulation of intracellular calcium leading to an inactivation of calcium currents, combined with small contributions of an accumulation of extracellular potassium and a summation of slow potassium conductances.

scholarly journals Postsynaptic activation at the squid giant synapse by photolytic release of L-glutamate from a ‘caged’ L-glutamate.

1993 ◽  
Vol 465 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J E Corrie ◽  
A DeSantis ◽  
Y Katayama ◽  
K Khodakhah ◽  
J B Messenger ◽  
...  
Keyword(s):  
Squid Giant Synapse ◽  
Giant Synapse

scholarly journals Enhanced synaptic transmission at the squid giant synapse by artificial seawater based on physically modified saline

2014 ◽  
Vol 6 ◽  
Author(s):  
Soonwook Choi ◽  
Eunah Yu ◽  
Guilherme Rabello ◽  
Suelen Merlo ◽  
Ajmal Zemmar ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Artificial Seawater ◽  
Squid Giant Synapse ◽  
Giant Synapse
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