Age-dependent changes in the regulation mechanisms for intracellular calcium ions in ganglion cells of the mouse retina.
Eur J Neurosci
; 22(11): 2735-43, 2005 Dec.
Article
em En
| MEDLINE
| ID: mdl-16324107
ABSTRACT
The purpose of this study was to investigate the role of intracellular calcium buffering in retinal ganglion cells. We performed a quantitative analysis of calcium homeostasis in ganglion cells of early postnatal and adult mice by simultaneous patch-clamp recordings in sliced tissue and microfluorometric calcium measurements with Fura-2. Endogenous calcium homeostasis was quantified by using the 'added buffer' approach which uses amplitudes and decay time constants of calcium transients to give a standard for intracellular calcium buffering. The recovery phase of depolarization-induced calcium transients was well approximated by a mono-exponential function with a decay time constant that showed a linear dependence on dye concentration. Endogenous calcium binding ratios were found to be 575 (n = 18 cells) in early postnatal and 121 (n = 18 cells) in adult retinal ganglion cells. With respect to ganglion cell degeneration at early postnatal stages, our measurements suggest that neuroprotection of a majority of developing ganglion cells partially results from a specialized calcium homeostasis based on high buffering capacities. Furthermore, the dramatic decrease of the intracellular calcium buffering capacity during ganglion cell development may enhance their vulnerability to neurodegeneration.
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Base de dados:
MEDLINE
Assunto principal:
Células Ganglionares da Retina
/
Envelhecimento
/
Cálcio
Limite:
Animals
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article