Evaluation of cellular mechanisms for modulation of calcium transients using a mathematical model of fura-2 Ca2+ imaging in Aplysia sensory neurons.
A theoretical model of [Ca++]i diffusion, buffering, and extrusion was developed for Aplysia sensory neurons, and integrated with the measured optical transfer function of our fura-2 microscopic recording system, in order to fully simulate fura-2 video or photomultiplier tube measurements of [Ca++]i. This allowed an analysis of the spatial and temporal distortions introduced during each step of fura-2 measurements of [Ca++]i in cells. In addition, the model was used to evaluate the plausibility of several possible mechanisms for modulating [Ca++]i transients evoked by action potentials. The results of the model support prior experimental work (Blumenfeld, Spira, Kandel, and Siegelbaum, 1990. Neuron. 5: 487-499), suggesting that 5-HT and FMRFamide modulate action potential-induced [Ca++]i transients in Aplysia sensory neurons through changes in Ca++ influx, and not through changes in [Ca++]i homeostasis or release from internal stores.
Blumenfeld
H
H
Center for Neurobiology and Behavior, Howard Hughes Medical Institute, Columbia University, New York, New York 10032.
Zablow
L
L
Sabatini
B
B
D000200:Action Potentials; D000818:Animals; D001048:Aplysia; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003198:Computer Simulation; D016257:Fura-2; D007700:Kinetics; D008433:Mathematics; D008962:Models, Theoretical; D009475:Neurons, Afferent / Q000502:physiology*; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D002118:Calcium; D016257:Fura-2