Relationship between light sensitivity and intracellular free Ca concentration in Limulus ventral photoreceptors. A quantitative study using Ca-selective microelectrodes.

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Relationship between light sensitivity and intracellular free Ca concentration in Limulus ventral photoreceptors. A quantitative study using Ca-selective microelectrodes

The possible role of Ca ions in mediating the drop in sensitivity associated with light adaptation in Limulus ventral photoreceptors was assessed by simultaneously measuring the sensitivity to light and the intracellular free Ca concentration (Cai); the latter was measured by using Ca-selective microelectrodes. In dark-adapted photoreceptors, the mean resting Cai was 3.5 +/- 2.5 microM SD (n = ...

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Light-induced changes of sensitivity in Limulus ventral photoreceptors

The responses of Limulus ventral photoreceptors to brief test flashes and to longer adapting lights were measured under voltage clamp conditions. When the cell was dark adapted, there was a range of energy of the test flashes over which the peak amplitude of the responses (light-induced currents) was directly proportional to the flash energy. This was also true when test flashes were superposed...

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Light-activated channels in limulus ventral photoreceptors.

We have investigated the light-dependent conductance of the ventral photoreceptor of Limulus by using the patchclamp technique. Our results show that ionic channels open in response to the sensory stimulus in these cells. To prepare the photoreceptors for patch-clamp recording, the glial cells and connective tissue that surround the photoreceptor were removed by teasing them away using a suctio...

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Light-induced oxygen consumption in Limulus ventral photoreceptors does not result from a rise in the intracellular sodium concentration

Illumination of Limulus ventral photoreceptors leads to an increase in the intracellular concentration of sodium, [Na+]i, and to an increase in the consumption of O2 (delta QO2). After a 1-s light flash, it takes approximately 480 s for [Na+]i to return to within 10% of its preillumination level, whereas delta QO2 takes approximately 90 s. Thus, the delta QO2 is complete long before [Na+]i has ...

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ژورنال

عنوان ژورنال: Journal of General Physiology

سال: 1985

ISSN: 0022-1295,1540-7748

DOI: 10.1085/jgp.85.6.805