Optical recording of light-evoked calcium signals in the functionally intact retina

Optical recording of light-evoked calcium signals in the functionally intact retina

Winfried Denk* and
Peter B. Detwiler†

Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974

Edited by John E. Dowling, Harvard University, Cambridge, MA, and approved April 5, 1999 (received for review December 23, 1998)

Abstract

Using two-photon excitation of fluorescent indicator dyes, we measured calcium concentration transients in retinal ganglion and amacrine cells without destroying the light sensitivity of the retina by maximally activating or bleaching the photoreceptors. This allowed an immediate assessment of the cellular morphology and study of the calcium signals evoked by visual stimuli. Calcium dynamics in individual dendritic processes could be examined for extensive periods without deterioration and with little apparent phototoxicity at excitation wavelengths of from 930 to 990 nm. Light-evoked increases in calcium were resolved in ganglion- and amacrine-cell neurites, making it possible to use optical recording to study the relationship between calcium signaling and retinal function.

Footnotes

↵ * To whom reprint requests should be addressed at: Biological Computation Research Department, Room 1C463, Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, NJ 07974. e-mail: denk{at}bell-labs.com.
↵ † Present address: Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195.
This paper was submitted directly (Track II) to the Proceedings Office.
ABBREVIATIONS:

[Ca2+]i,

intracellular calcium concentration;

LED,

light-emitting diode;

n.a.,

numerical aperture