scholarly journals β-Scorpion toxin effects suggest electrostatic interactions in domain II of voltage-dependent sodium channels

2005 ◽  
Vol 568 (1) ◽  
pp. 13-30 ◽  
Author(s):  
Massimo Mantegazza ◽  
Sandrine Cestèle
Keyword(s):  
Sodium Channels ◽  
Electrostatic Interactions ◽  
Scorpion Toxin ◽  
Voltage Dependent

4-aminopyridine derivatives: A family of novel modulators of voltage-dependent sodium channels

1998 ◽  
Vol 44 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Lei Tang ◽  
Francis P. Huger ◽  
Joseph T. Klein ◽  
Larry Davis ◽  
Lawrence L. Martin ◽  
...  
Keyword(s):  
Sodium Channels ◽  
Voltage Dependent

Up-regulation of functional voltage-dependent sodium channels by cyclic AMP-dependent protein kinase in adrenal medulla

1996 ◽  
Vol 709 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Tomoaki Yuhi ◽  
Akihiko Wada ◽  
Ryuichi Yamamoto ◽  
Toshihiko Yanagita ◽  
Hiromi Niina ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Sodium Channels ◽  
Adrenal Medulla ◽  
Dependent Protein Kinase ◽  
Voltage Dependent ◽  
Dependent Protein

scholarly journals An excitatory scorpion toxin with a distinctive feature: an additional α helix at the C terminus and its implications for interaction with insect sodium channels

Structure ◽  
1998 ◽  
Vol 6 (9) ◽  
pp. 1095-1103 ◽  
Author(s):  
Deena A Oren ◽  
Oren Froy ◽  
Efrat Amit ◽  
Nurit Kleinberger-Doron ◽  
Michael Gurevitz ◽  
...  
Keyword(s):  
Sodium Channels ◽  
Distinctive Feature ◽  
Scorpion Toxin ◽  
C Terminus ◽  
Α Helix

scholarly journals α-Scorpion Toxin Impairs a Conformational Change that Leads to Fast Inactivation of Muscle Sodium Channels

2008 ◽  
Vol 132 (2) ◽  
pp. 251-263 ◽  
Author(s):  
Fabiana V. Campos ◽  
Baron Chanda ◽  
Paulo S.L. Beirão ◽  
Francisco Bezanilla
Keyword(s):  
Sodium Channels ◽  
Slow Component ◽  
Scorpion Toxin ◽  
Fast Inactivation ◽  
Gating Current ◽  
Voltage Sensors ◽  
Current Decay ◽  
Fluorescence Measurements ◽  
Gating Charge ◽  
Domain Iii

α-Scorpion toxins bind in a voltage-dependent way to site 3 of the sodium channels, which is partially formed by the loop connecting S3 and S4 segments of domain IV, slowing down fast inactivation. We have used Ts3, an α-scorpion toxin from the Brazilian scorpion Tityus serrulatus, to analyze the effects of this family of toxins on the muscle sodium channels expressed in Xenopus oocytes. In the presence of Ts3 the total gating charge was reduced by 30% compared with control conditions. Ts3 accelerated the gating current kinetics, decreasing the contribution of the slow component to the ON gating current decay, indicating that S4-DIV was specifically inhibited by the toxin. In addition, Ts3 accelerated and decreased the fraction of charge in the slow component of the OFF gating current decay, which reflects an acceleration in the recovery from the fast inactivation. Site-specific fluorescence measurements indicate that Ts3 binding to the voltage-gated sodium channel eliminates one of the components of the fluorescent signal from S4-DIV. We also measured the fluorescent signals produced by the movement of the first three voltage sensors to test whether the bound Ts3 affects the movement of the other voltage sensors. While the fluorescence–voltage (F-V) relationship of domain II was only slightly affected and the F-V of domain III remained unaffected in the presence of Ts3, the toxin significantly shifted the F-V of domain I to more positive potentials, which agrees with previous studies showing a strong coupling between domains I and IV. These results are consistent with the proposed model, in which Ts3 specifically impairs the fraction of the movement of the S4-DIV that allows fast inactivation to occur at normal rates.

scholarly journals Allosteric stimulation of voltage-dependent sodium channels by brevetoxin in cultured bovine adrenal medullary cells

1992 ◽  
Vol 58 ◽  
pp. 268
Author(s):  
Akihiko Wada ◽  
Yasuhito Uezono ◽  
Tomoaki Yuhi ◽  
Hideyuki Kobayashi ◽  
Nobuyuki Yanagihara ◽  
...  
Keyword(s):  
Sodium Channels ◽  
Adrenal Medullary Cells ◽  
Voltage Dependent ◽  
Stimulation Of ◽  
Medullary Cells
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