The A-like potassium current of a leech neuron increases with age in cell culture |
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Authors: | Tribut F Calabrese B Pellegrino M |
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Institution: | (1) Dipartimento di Fisiologia e Biochimica `G. Moruzzi', Universitá di Pisa, Via S. Zeno 31, I-56127 Pisa Italy e-mail: marpell@dfb.unipi.it, Tel.: +39-0-50-553517/00-554074, Fax: +39-0-50-552183, IT |
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Abstract: | Single leech neurons isolated and maintained in culture sprout and form electrical and chemical synapses, as they do in vivo,
retaining most of the electrical properties of the intact membrane. However, some cells, such as Retzius, Anterior Pagoda
(AP) cells and motoneurons, exhibit consistent changes of biophysical characteristics, which mimic those induced by axotomy
in vivo and are reversed after reconnection. To improve our understanding of the mechanisms involved in these alterations
and of their physiological significance, we investigated the early changes in outward currents developed by cultured AP neurons,
using the patch-clamp technique in the whole-cell recording configuration. Different currents were isolated and a differential
sensitivity to the time spent in culture and to internal calcium was observed. Three potassium currents were dissected: an
A-like current, a delayed rectifier and a third unidentified component. The A-like potassium current was significantly increased
with neuronal age in cell culture and was a function of the internal Ca2+ concentration, whereas the two other potassium currents remained unchanged. Intracellular recordings performed from axotomized
neurons of cultured ganglia revealed clear-cut alterations in spike adaptation, which might be due to changes of the A-like
current.
Accepted: 24 September 1998 |
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Keywords: | Leech Potassium currents Patch-clamp Axotomy Regeneration |
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