Referenced in: none

Automatically associated channels: Kv4.1 , Slo1

Title: The permeation and activation properties of brain sodium channels change during development.

Authors: Cecilia Castillo, William B Thornhill, Jing Zhu, Esperanza Recio-Pinto

Journal, date & volume: Brain Res. Dev. Brain Res., 2003 Aug 12 , 144, 99-106

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/12888221

Abstract
BTX-modified sodium channels from 15-day embryonic (E15) rat forebrains were studied in planar lipid bilayers. Compared to postnatal sodium channels, E15 channels had a lower maximal single channel conductance, whereas their permeation pathway sensed a comparable surface charge density and had a similar apparent binding affinity for sodium ions. The steady-state activation curve of E15 channels was significantly more hyperpolarized and had a shallower slope than postnatal channels. The apparent BTX binding affinity was significantly lower for E15 channels than for postnatal channels. Finally, E15 channel alpha-subunits displayed a lower apparent molecular weight, and a lower sialylation level than postnatal sodium channel alpha-subunits. Together with previous studies, our data suggested that the observed functional differences between E15 and postnatal voltage-dependent sodium channels cannot be explained solely by the observed differences in channel sialylation, and hence they also appeared to reflect the presence of other channel structural differences.