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ID 37943
file
creator
Yakehiro, Masuhide
subject
Sodium channel
Polyamine
Frog ventricular cells
Block
NDC
Medical sciences
abstract
The mechanism underlying the Na channel blocking action of guanidyl-side armed cyclam (G-cyclam) was studied using conventional patch-clamp methods. G-cyclam applied to the cytoplasmic surface of the membrane reduced the amplitude of single Na channel currents without inducing a flickering block. This effect was enhanced by depolarization and was fully reversible upon washout of the drug. The relationship between the concentration of G-cyclam and the reduction of unitary current could be expressed mathematically assuming one-to-one stoichiometry. During maximal suppression of the single channel current by G-cyclam approximately 40% of the current remained. Low concentration of G-cyclam (3×10-4M) prolonged, while higher concentration (3×10-3M) shortened the mean open time suggesting the involvement of two processes in the Na channel blocking action of this agent. It appears that low concentration of G-cyclam induce rapid and frequent transition between open and less conductive state resulting in a reduced current, and higher concentration make the channel nonconductive with slower single channel kinetics.
description
This work was supported in part by a Grant-in-Aid from the Ministry of Education, Science and Culture of Japan and a grant from the Tsuchiya Foundation.
journal title
Hiroshima Journal of Medical Sciences
volume
Volume 41
issue
Issue 3
start page
49
end page
55
date of issued
1992-09
publisher
Hiroshima University Medical Press
issn
0018-2052
ncid
pubmed id
language
eng
nii type
Departmental Bulletin Paper
HU type
Departmental Bulletin Papers
DCMI type
text
format
application/pdf
text version
publisher
department
Graduate School of Biomedical Science
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