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. 1977 Feb;74(2):623–627. doi: 10.1073/pnas.74.2.623

Free calcium increases explosively in activating medaka eggs.

E B Ridgway, J C Gilkey, L F Jaffe
PMCID: PMC392344  PMID: 322135

Abstract

We have used the calcium-specific light-emitting protein aequorin to follow changes in free calcium concentration during fertilization and cleavage of eggs from medaka, a fresh-water fish. Aequorin-injected medaka eggs show a very low resting glow before they are fertilized, indicating a low calcium concentration in the resting state. Upon activation by sperm, the calcium-mediated light emission increases to a level some 10,000 times the resting level with a 1 to 2 sec time constant for an e-fold increase, and then slowly retruns to the resting level. Upon activation by the ionophore A23187, the early rise in luminescence is much slower, but once a threshold has been reached the subsequent rise becomes as rapid as the normal sperm-induced response. We infer that the explosive rise in calcium involves calcium-stimulated calcium release, and that a sperm normally triggers this rise by somehow inducing a more modest and localized rise in calcium.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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