Effects of fluctuations on electrical properties of gap-junction connected cells in the turtle retina.
Electrical properties of gap-junction connected cells (input voltage and length constant) are shown to depend strongly on fluctuations in membrane and contact conductances. This opens new possibilities and incorporates a further difficulty to the analysis of electrophysiological data, since four, instead of two, parameters (the average values and the magnitude of fluctuations of the two conductances) have to be used in fitting the experimental data. The discussion is illustrated by investigating the effects of dopamine on signal spreading in horizontal cells of turtle retina, assuming a linear cell arrangement. It is shown that while a standard fitting with the average values of the two conductances leads to the conclusion that both are equally affected by dopamine, including fluctuations allows fitting the data by varying just the average contact conductance plus the magnitude of fluctuations.
Louis
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E
Departamento de Física Aplicada and Unidad Asociada of the Consejo Superior de Investigaciones Científicas, Universidad de Alicante, Apartado 99, E-03080, Alicante, Spain. enrique@fisic1.ua.es
Degli Esposti Boschi
C
C
Ortega
G
G
Andreu
E
E
Fernández
E
E
Sánchez-Andrés
J V
JV
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000502:physiology; D004553:Electric Conductivity; D017629:Gap Junctions / Q000502:physiology*; D012160:Retina / Q000502:physiology*; D014426:Turtles
D004298:Dopamine