Document Detail

Triton detergents and the frog neuromuscular end-plate: an electrophysiological and ultrastructural study.
MedLine Citation:
PMID:  308765     Owner:  NLM     Status:  MEDLINE    
The effects of the nonionic detergents Triton X-45 and Triton X-100 were studied in the frog muscle end-plate, by intracellular recordings of spontaneous miniature end-plate potentials (m.e.p.p.'s) and the potential changes produced by iontophoretic application of acetylcholine (ACh-potentials). In addition, the ultrastructural changes produced by Triton X-100 were studied by transmission electron microscopic and freeze-fracture techniques. It was found that Triton X-45 and Triton X-100 caused a rapidly developing reduction of the amplitude of the m.e.p.p.'s. The response to iontophoretic application of acetylcholine was reduced by Triton X-100. Following return to normal Ringer solution the ACh-potentials recovered, although not completely. The dissociation constant calculated from the rate constants for onset and offset of the reaction (Kp=k2/k1) was 5--50 micron depending on the type of stoichiometric reaction presumed to occur between Triton X-100 and the cholinergic receptor. The ultrastructural changes observed indicate that the nerve terminal plasma membrane and mitochondria are affected by Triton X-100. Leakage of Ca2+ from the latter may therefore be the cause of the increase in m.e.p.p. frequency. It is concluded that the influence on the amplitude of the m.e.p.p.'s and the ACh-potentials can be attributed to a direct effect of the detergent upon the acetylcholine receptor protein.
B Rydqvist
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Acta physiologica Scandinavica     Volume:  104     ISSN:  0001-6772     ISO Abbreviation:  Acta Physiol. Scand.     Publication Date:  1978 Sep 
Date Detail:
Created Date:  1978-11-29     Completed Date:  1978-11-29     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0370362     Medline TA:  Acta Physiol Scand     Country:  SWEDEN    
Other Details:
Languages:  eng     Pagination:  82-100     Citation Subset:  IM    
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MeSH Terms
Acetylcholine / physiology
Freeze Fracturing
Membrane Potentials / drug effects
Microscopy, Electron
Motor Endplate / drug effects*,  ultrastructure
Muscles / innervation,  ultrastructure
Neuromuscular Junction / drug effects*
Polyethylene Glycols / pharmacology*
Rana temporaria
Synaptic Membranes / ultrastructure
Synaptic Vesicles / ultrastructure
Reg. No./Substance:
0/Polyethylene Glycols; 51-84-3/Acetylcholine

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