Functional reconstitution of the purified sodium channel protein from rat sarcolemma.
Publication/Presentation Date
6-1-1982
Abstract
The purified saxitoxin (STX) binding component of the rat sarcolemmal sodium channel (SBC) has been reconstituted into phospholipid vesicles. The reconstituted SBC displays the pharmacological properties and the ability to control sodium fluxes expected of a functional sodium channel. Batrachotoxin (BTX) increases 22Na+ influx into reconstituted SBC vesicles by greater than 100% over control at early time points. The BTX-stimulated 22Na+ influx is specifically and quantitatively blocked by STX. Veratridine and aconitine also stimulate Na+-flux--although less effectively than BTX--in the order: BTX greater than veratridine greater than aconitine. The logarithmic dose--response curves for BTX and veratridine are sigmoidal with a K0.5 of 1.5 microM and 35 microM, respectively. Vesicles containing the reconstituted SBC demonstrate 3H-labeled STX binding to a single class of high affinity sites witha Kd of 5--7 nM at 0 degrees C; the thermal stability of the STX receptor is markedly enhanced by reconstitution. Our results confirm that the purified STX binding component from rat sarcolemma constitutes the sodium channel itself and contains at least those components sufficient for channel activation, transmembrane ion movement, and inhibition by STX.
Volume
79
Issue
11
First Page
3651
Last Page
3655
ISSN
0027-8424
Published In/Presented At
Weigele, J. B., & Barchi, R. L. (1982). Functional reconstitution of the purified sodium channel protein from rat sarcolemma. Proceedings of the National Academy of Sciences of the United States of America, 79(11), 3651–3655. https://doi.org/10.1073/pnas.79.11.3651
Disciplines
Diagnosis | Medicine and Health Sciences | Other Analytical, Diagnostic and Therapeutic Techniques and Equipment | Radiology
PubMedID
6285356
Department(s)
Department of Radiology and Diagnostic Medical Imaging
Document Type
Article