Activity-dependent calcium transients in central nervous system myelinated axons revealed by the calcium indicator Fura-2.
Optical measurements from rat optic nerve, loaded with the new Ca2+ indicator Fura-2, provide the first evidence for the presence of activity-dependent fast intracellular [Ca2+] transients in mammalian central nervous system (CNS) myelinated axons. The results suggest that voltage-dependent Ca2+ channels are present in some of the myelinated axons. Optical measurements from axons stained with anterogradely transported voltage-sensitive dye suggest the presence of Ca2+-dependent potassium conductances in these axons. This report also demonstrates that Fura-2 can readily detect changes in [Ca2+] inside cells as a result of electrical activity, and establishes its suitability for measurements of intracellular Ca2+ transients in the millisecond time domain.
Lev-Ram
V
V
Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.
Grinvald
A
A
D000818:Animals; D001369:Axons / Q000502:physiology*; D001572:Benzofurans; D002118:Calcium / Q000502:physiology*; D005456:Fluorescent Dyes; D016257:Fura-2; D066298:In Vitro Techniques; D008564:Membrane Potentials; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D009431:Neural Conduction; D009900:Optic Nerve / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D001572:Benzofurans; D005456:Fluorescent Dyes; D002118:Calcium; D016257:Fura-2