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FZJ-2018-01891

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Simultane Messungen des lichtinduzierten Ionenstroms in Abhängigkeit von der Membranspannung und der intrazellulären Calciumionen-Konzentrationsänderungen nach Injektion von Arsenazo III : Messungen am Ventralnerv-Photorezeptor von Limulus Polyphemus

Ivens, I. (Corresponding author)FZJ*

1982
Kernforschungsanlage Jülich, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/17693

Report No.: Juel-1794

Abstract: 1. Methods: The light induced membrane current of the ventral photoreceptor cell of Limulus polyphemus was studied using the voltage clamp technique. During the experiments transmission changes of the calcium sensitive dye Arsenazo III, which had been injected into the cells, was recorded at 645 nm. 2. Results: The level of free calcium ions in a ventral photoreceptor cell increases in response to light (Brown & Blinks, 1974; Brown et al., 1977). After injection of Arsenazo III a decrease of the cell transmission at 645 nm (s. Fig. 7) can be seen in response to light both in the unclamped cell and when the membrane is held under voltage clamp. This transmission change is caused by the light induced increase in intracellular free calcium (Brown et al., 1977; Maaz & Stieve, 1980; Nagy & Stieve, 1982). The voltage clamp experiments show that the light induced transmission changes depend on the membrane voltage of the photoreceptor cello I. The height of the Arsenazo signal* decreases with increasing clamp voltage (s. Fig. 11a). In salines with reduced extracellular calcium (250 $\mu$mol/l) this effect is more pronounced. In salines with increased extracellular calcium concentration there is almost no change of the Arsenazo signal with the clamp voltage. This indicates that there is a light induced influx of calcium ions from extracellular space through the cell membrane into the cytoplasma. However the data do not exclude the possibility that part of the calcium ions responsible for the Arsenazo signal is released from intracellular calcium stores (Walz, 1979; Carafoli, 1981). *Arsenazo signal means the light induced transmission decrease with its 'maximum' ca. 200 ms after a short light flash. The 'maximum' is followed by a slower increase of transmission back to the value before the light flash. [...]

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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