Document Detail


Effects of the lonophore A23187 on the blood platelets II. Influence on ultrastructure.
MedLine Citation:
PMID:  4447125     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A23187, an ionophore which selectively transports calcium across cell membranes into cytoplasm or releases the divalent cation from intracellular storage sites, was shown in previous studies to stimulate platelet aggregation and the release reaction. The nature of its influence on platelet function suggested that an increase in cytoplasmic calcium ion concentration might be a critical factor linking stimulation to secretion through the platelet contractile mechanism. The present investigation has examined the effects of A23187 in platelet ultrastructure and aggregation after incubation with various concentrations of the drug. Scanning and transmission electron microscopy revealed changes in the form and internal organization of platelets following exposure to A23187 that were identical to those which develop in the cells after exposure to potent agents such as collagen and thrombin. High concentrations of ionophore caused destruction of the platelets on prolonged incubation, while the effects of low concentrations on structure and aggregation reversed completely. Recovered platelets were as sensitive to other aggregating agents as control cells. The findings support the concept that platelets are a form of muscle cell and the internal transformation stimulated by A23187 and other aggregating agents is a manifestation of contractile activity. Inactivation of A23187 by plasma followed by recovery of unaltered appearance indicates that platelets have an active mechanism for reducing the level of cytoplasmic calcium.
Authors:
J M Gerrard; J G White; G H Rao
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The American journal of pathology     Volume:  77     ISSN:  0002-9440     ISO Abbreviation:  Am. J. Pathol.     Publication Date:  1974 Nov 
Date Detail:
Created Date:  1975-04-17     Completed Date:  1975-04-17     Revised Date:  2010-06-22    
Medline Journal Info:
Nlm Unique ID:  0370502     Medline TA:  Am J Pathol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  151-66     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Adenosine Diphosphate / pharmacology
Anti-Bacterial Agents / adverse effects,  pharmacology*
Blood Platelets / drug effects*,  metabolism,  secretion,  ultrastructure
Calcium / metabolism*,  physiology
Carboxylic Acids / antagonists & inhibitors,  pharmacology
Collagen / pharmacology
Cytoplasm / metabolism
Cytoplasmic Granules / ultrastructure
Dimethyl Sulfoxide / pharmacology
Epinephrine / pharmacology
Glycogen / metabolism
Humans
Microscopy, Electron
Microscopy, Electron, Scanning
Microtubules / ultrastructure
Mitochondria / ultrastructure
Muscles / cytology
Organoids / ultrastructure
Platelet Aggregation / drug effects
Thrombin / pharmacology
Chemical
Reg. No./Substance:
0/Anti-Bacterial Agents; 0/Carboxylic Acids; 51-43-4/Epinephrine; 58-64-0/Adenosine Diphosphate; 67-68-5/Dimethyl Sulfoxide; 7440-70-2/Calcium; 9005-79-2/Glycogen; 9007-34-5/Collagen; EC 3.4.21.5/Thrombin
Comments/Corrections

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