Publication Date:
1985-07-12
Description:
A specific label for voltage-dependent calcium channels is essential for the isolation and purification of the membrane protein that constitutes the calcium channel and for a better understanding of its function. A fraction of Crotalus atrox that increases voltage-dependent calcium currents in single, dispersed guinea pig ventricular cells was isolated. In the doses used, neither sodium nor potassium currents were changed. The fraction was active in the absence of detectable phospholipase or protease activity, and the active component, designated atrotoxin, produced its effect rapidly and reversibly. The effect was produced by extracellular but not intracellular application of the agent. The increase in Ca2+ current was blocked by the Ca2+ channel blockers cobalt and nitrendipine. The active fraction completely blocked specific [3H]nitrendipine binding to guinea pig ventricular membrane preparations. The inhibition of nitrendipine binding by atrotoxin was apparently via an allosteric mechanism. Thus atrotoxin was shown to bind to the Ca2+ channel and to act as a specific Ca2+ channel agonist.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hamilton, S L -- Yatani, A -- Hawkes, M J -- Redding, K -- Brown, A M -- 1R01 HL3293S/HL/NHLBI NIH HHS/ -- 1R01-HL33662-01/HL/NHLBI NIH HHS/ -- 5R01-HL25145-05/HL/NHLBI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1985 Jul 12;229(4709):182-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3160111" target="_blank"〉PubMed〈/a〉
Keywords:
Action Potentials/drug effects
;
Animals
;
Calcium/*metabolism
;
Cell Membrane/metabolism
;
Crotalid Venoms/*pharmacology
;
Dose-Response Relationship, Drug
;
Guinea Pigs
;
In Vitro Techniques
;
Molecular Weight
;
Myocardium/*metabolism
;
Nifedipine/analogs & derivatives/metabolism
;
Nitrendipine
;
Potassium/metabolism
;
Rats
;
Sodium/metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
