|Title:||Simulation of the synaptic exocytosis of bipolar cells in the electrically stimulated mammalian retina||Other Titles:||Simulation der Neurotransmitterausschüttung von Bipolarzellen der elektrisch stimulierten Retina||Language:||English||Authors:||Bassereh Moosaabadi, Hassan||Qualification level:||Doctoral||Advisor:||Rattay, Frank||Issue Date:||2019||Number of Pages:||148||Qualification level:||Doctoral||Abstract:||
The output of the retinal bipolar neurons has two components, i.e., transient and sustained neurotransmitter releases, which is not common at chemical synapses. This uniqueness originates from an extra protein structure called 'ribbon'. Transient outputs take place exactly after a large enough stimulus, while sustained outputs occur at any state with a different rate. We presented two models to simulate both releases from a terminal of a rat rod bipolar cell, but the approach can be applied for any type of bipolar cells. One of the models is based on transmembrane voltage of terminals and the other is based on intracellular calcium concentration of terminals, each of which is explained by two time dependent equations. Intracellular calcium concentration method bring a 0.43 ms signal delay observable in xperiments, while the other model has no delay. By comparing responses of spiking and non-spiking bipolar cells stimulated intracellularly, it was proposed that a spike causes the release of all of the available vesicles rapidly (transient releases), while the non-spiking cell release no vesicle at the same stimulus amplitude. Effect of extracellular stimulation generated by a single microelectrode, on transient release almost suggested no difference between responses of active and passive cells in short pulses because terminal membrane of the cells in both cases senses the same potentials originating from the microelectrode. However, spiking-bipolar cells release more transient vesicles in pulses with long duration since spike has enough time to reach to the terminal leading to release of more transient vesicles. Effect of periodic stimulation on ribbon recovery when the cell is stimulated both intraor extracellularly also suggested that for 5 Hz stimulations, only three transient vesicles are released from a single ribbon per stimulus.
|Keywords:||ribbon synapse; retina; bipolar cell; stimulation; simulation||URI:||https://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-126035
|Library ID:||AC15391421||Organisation:||E101 - Institut für Analysis und Scientific Computing||Publication Type:||Thesis
|Appears in Collections:||Thesis|
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checked on May 27, 2021
checked on May 27, 2021
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