TY - JOUR
T1 - The permeation and activation properties of brain sodium channels change during development
AU - Castillo, Cecilia
AU - Thornhill, William B.
AU - Zhu, Jing
AU - Recio-Pinto, Esperanza
N1 - Funding Information:
This work was partially supported by the Vollmer Research Fund of the Centro de Estudios Cientı́ficos de Caracas (CEC-Caracas), and the Fundación Pro Ciencia by CONICIT (Venezuela) grants S1-95000727 (CC) and NIH grants NS29633 (WBT) and GM50686 (ERP). Special thanks to Dr John Daly who provided the BTX used during this work.
PY - 2003/8/12
Y1 - 2003/8/12
N2 - 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 α-subunits displayed a lower apparent molecular weight, and a lower sialylation level than postnatal sodium channel α-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.
AB - 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 α-subunits displayed a lower apparent molecular weight, and a lower sialylation level than postnatal sodium channel α-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.
KW - Channel function during development
KW - Glycosylation
KW - Rat forebrain
KW - Sialylation
KW - Voltage-dependent sodium channel
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U2 - 10.1016/S0165-3806(03)00164-0
DO - 10.1016/S0165-3806(03)00164-0
M3 - Article
C2 - 12888221
AN - SCOPUS:0042347560
SN - 0165-3806
VL - 144
SP - 99
EP - 106
JO - Developmental Brain Research
JF - Developmental Brain Research
IS - 1
ER -