TY - JOUR
T1 - Single-channel properties of the reconstituted voltage-regulated Na channel isolated from the electroplax of Electrophorus electricus.
AU - Rosenberg, R. L.
AU - Tomiko, S. A.
AU - Agnew, W. S.
PY - 1984
Y1 - 1984
N2 - The tetrodotoxin-binding protein purified from electroplax of Electrophorus electricus has been reincorporated into multilamellar vesicles that were used for patch recording. When excised patches of these reconstituted membranes were voltage clamped in the absence of neurotoxins, voltage-dependent single-channel currents were recorded. These displayed properties qualitatively and quantitatively similar to those reported for Na channels from nerve and muscle cells, including uniform single-channel conductances of the appropriate magnitude (approximately equal to 11 pS in 95 mM Na+), mean open times of approximately equal to 1.9 msec, and 7-fold selectively for Na+ over K+. Currents averaged from many depolarizations showed initial voltage-dependent activation and subsequent inactivation. In the presence of batrachotoxin, channels were observed with markedly different properties, including conductances of 20-25 pS (95 mM Na+), mean open times of approximately equal to 28 msec, and no indication of inactivation. Collectively, these findings indicate that the tetrodotoxin-binding protein of electroplax is a voltage-regulated sodium channel.
AB - The tetrodotoxin-binding protein purified from electroplax of Electrophorus electricus has been reincorporated into multilamellar vesicles that were used for patch recording. When excised patches of these reconstituted membranes were voltage clamped in the absence of neurotoxins, voltage-dependent single-channel currents were recorded. These displayed properties qualitatively and quantitatively similar to those reported for Na channels from nerve and muscle cells, including uniform single-channel conductances of the appropriate magnitude (approximately equal to 11 pS in 95 mM Na+), mean open times of approximately equal to 1.9 msec, and 7-fold selectively for Na+ over K+. Currents averaged from many depolarizations showed initial voltage-dependent activation and subsequent inactivation. In the presence of batrachotoxin, channels were observed with markedly different properties, including conductances of 20-25 pS (95 mM Na+), mean open times of approximately equal to 28 msec, and no indication of inactivation. Collectively, these findings indicate that the tetrodotoxin-binding protein of electroplax is a voltage-regulated sodium channel.
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U2 - 10.1073/pnas.81.17.5594
DO - 10.1073/pnas.81.17.5594
M3 - Article
C2 - 6089214
AN - SCOPUS:0021491209
SN - 0027-8424
VL - 81
SP - 5594
EP - 5598
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 17
ER -