Intranuclear Ca2+ transients during neurite regeneration of an adult mammalian neuron.

AUTOR(ES)

Birch, B D

RESUMO

Depolarization-induced increases in cytoplasmic and intranuclear Ca2+ were visualized in adult mammalian dorsal root ganglion (DRG) neurons during different stages of neurite extension by using confocal laser scanning microscopy and the long-wavelength Ca2+ indicator dye fluo 3-AM (acetoxymethyl ester of fluo 3). In neurons beginning to extend neurites, depolarization led to pronounced increases in nuclear and nucleolar Ca2+ levels severalfold greater than corresponding increases in the cytoplasm. The nucleolar Ca2+ signal often exceeded that of the nucleus, indicating regional heterogeneity of the nucleus. The subcellular calcium transients were dependent on extracellular Ca2+ and the level of depolarization, indicating the importance of transmembrane Ca2+ fluxes in triggering the nuclear events. After neurite extension, the nuclear Ca2+ signals were attenuated and never exceeded cytoplasmic levels. These results indicate that activity-dependent modulation of intranuclear Ca2+ levels is greater in DRG neurons during early neurite extension. Given the importance of Ca2+ in gene expression, the results may be relevant to Ca(2+)-dependent nuclear events responsible for axonal regeneration.

Documentos Relacionados

• Transient low-threshold Ca2+ current triggers burst firing through an afterdepolarizing potential in an adult mammalian neuron.
• Presynaptic inhibition in Aplysia involves a decrease in the Ca2+ current of the presynaptic neuron.
• Enhancement by muscarinic agonists of a high voltage-activated Ca2+ current via phosphorylation in a snail neuron.
• Transformation of local Ca2+ spikes to global Ca2+ transients: the combinatorial roles of multiple Ca2+ releasing messengers
• Low-Affinity Ca2+ Indicators Compared in Measurements of Skeletal Muscle Ca2+ Transients