PT  - JOURNAL ARTICLE
AU  - MR Wood
AU  - J DeBin
AU  - GR Strichartz
AU  - KH Pfenninger
TI  - Plasmalemmal insertion and modification of sodium channels at the nerve growth cone
AID  - 10.1523/JNEUROSCI.12-08-02948.1992
DP  - 1992 Aug 01
TA  - The Journal of Neuroscience
PG  - 2948--2959
VI  - 12
IP  - 8
4099  - http://www.jneurosci.org/content/12/8/2948.short
4100  - http://www.jneurosci.org/content/12/8/2948.full
SO  - J. Neurosci.1992 Aug 01; 12
AB  - We have characterized voltage-dependent sodium channels in growth cones (GCPs) isolated from fetal rat brain using saxitoxin and TTX binding as well as recordings from channels reconstituted into lipid bilayer membranes. Both high- and low-affinity binding sites are present in GCP membranes. However, the two binding sites are segregated largely or completely, with the high-affinity binding sites in the plasmalemma, and the low-affinity sites in an internal membrane compartment. Plasmalemmal insertion of these internal sites can be triggered by high- potassium depolarization and depends on a metalloendoprotease-requiring mechanism. These observations indicate that a precursor-product relationship exists between the internal and external sodium channels of the growth cone, and therefore suggest that channel externalization causes conversion of low-affinity to high-affinity saxitoxin receptors. This conversion may represent a step of channel capacitation.