Evidence for light-induced release of Ca2+ from intracellular stores in bee photoreceptors.
In the drone retina light elicits an increase in the extracellular Ca2+ concentration ([Ca]o). After withdrawal of extracellular Ca2+ and addition of 1 mM EGTA (ethyleneglycol-bis (beta-aminoethyl ether) N,N,N',N'-tetraacetic acid) a short light flash still caused an increase in [Ca]o as measured with Ca2(+)-sensitive microelectrodes. This increase vanished after a few flashes. When [Ca]o was reduced to 10(-5) M Ca2+ (no EGTA) the rise in Cao disappeared after several light flashes. Subsequent stimulation with a dim steady light produced a decrease in [Ca]o and caused a recovery of the increase in [Ca]o elicited by a test flash. The results show that bee photoreceptors have a light-depletable intracellular Ca2+ store which can be reloaded by dim continuous lights.
Ziegler
A
A
Institut für Zoologie, Universität Regensburg, F.R.G.
Walz
B
B
D000818:Animals; D001516:Bees / Q000378:metabolism / Q000502:physiology*; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D066298:In Vitro Techniques; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000378:metabolism / Q000502:physiology*
D002118:Calcium