WALZ, B and ZIMMERMANN, B and SEIDL, S (1994) INTRACELLULAR CA2+ CONCENTRATION AND LATENCY OF LIGHT-INDUCED CA2+ CHANGES IN PHOTORECEPTORS OF THE HONEYBEE DRONE. JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY, 174 (4). pp. 421-431. ISSN 0340-7594, 1432-1351
Full text not available from this repository.Abstract
We have measured Cai at rest and upon light stimulation in the photoreceptors of the honeybee drone microfluorometrically with the fluorescent Ca2+ indicator dyes fura-2, fluo-3 and Ca-green 5N. In darkness, Ca, was similar to 90 nM after 5 min of dark adaptation. A saturating light step caused Ca-i to rise in the bulk cytoplasm to similar to 750 nM within 1 s. Our measurements with the low affinity dye Ca-green 5N showed that bright 1-s light flashes cause a rapid increase in Ca-i, which was graded with stimulus intensity. Ca-green 5N fluorescence reached a peak in about 200 ms, and then decayed to a slightly lower sustained plateau. The fluorescence signal peaked, when the receptor potential was repolarizing from its peak to the plateau. This observation is in agreement with the proposal that the peak-to-plateau transition of the receptor potential is caused by the rise in Ca-i. From our Fluo-3 measurements it appears that the latency of the Ca2+ increase is by 3-4 ms longer than the latency of the receptor potential elicited by bright 100-ms light flashes. This result provides no support for the proposal that Ca2+ mediates the opening of those membrane channels responsible for the upstroke of the receptor potential.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | LIMULUS VENTRAL PHOTORECEPTORS; APIS-MELLIFERA-MALE; ENDOPLASMIC-RETICULUM; CALCIUM RELEASE; INOSITOL 1,4,5-TRISPHOSPHATE; DROSOPHILA PHOTORECEPTORS; EXTRACELLULAR CALCIUM; COMPOUND EYE; BEE DRONE; RETINA; PHOTOTRANSDUCTION; PHOTORECEPTOR; CYTOPLASMIC CALCIUM; MICROFLUOROMETRY; BEE |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:40 |
| URI: | https://pred.uni-regensburg.de/id/eprint/53361 |
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