Voltage activated currents were studied in whole-cell patch-clamped rat neocortical neurons growing in culture and treated with tunicamycin (TU), an inhibitor of protein N-glycosylation. The size of the Na + current decreased progressively in the presence of TU (1-2 μM). This decrease was faster in growing 5-14 day-old neurons (to ca. 40% of control after 24 hours of treatment) than in fully grown 20-40-day-old neurons (to ca. 40% of control after 68 hours of treatment). The fast transient K + current (A-current) was abolished, and the delayed rectifier K + current was markedly reduced by a 24 hour treatment with TU (1-2 μM) in growing neurons. In contrast, in fully grown neurons these currents were unaffected by the same TU treatment. The size of the Ca 2+ current was significantly reduced following a 24 hour treatment with TU (1-2 μM) in neurons at early stages of differentiation, but remained stable in 20-40-day-old neurons. It is concluded that protein glycosylation, presumably of the channel proteins themselves, is important for the functional expression of voltage-activated channels in embryonic cortical neurons during the early stages of cell growth in culture; the channels become less dependent on glycosylation in mature neurons.
|Number of pages||9|
|Journal||Proceedings of the Royal Society B: Biological Sciences|
|Publication status||Published - 1990|
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Agricultural and Biological Sciences (miscellaneous)