Binding of Lambert-Eaton myasthenic syndrome IgG to synaptosomal proteins does not correlate with an inhibition of calcium uptake.

Abstract

The immunochemical and functional properties of IgG fractions from patients with Lambert-Eaton myasthenic syndrome (LEMS) were examined in chick and rat synaptosomes. LEMS IgG immunoprecipitated 125I-omega conotoxin GVIA (125I-omega CgTx) labeled N-type calcium channels solubilized from both tissues, and reacted with a 65 kDa protein band in immunoblots of rat synaptosomes. Depolarization-induced 45Ca2+ influx into chick synaptosomes was partially inhibited by omega CgTx, whereas influx into rat synaptosomes was insensitive to omega CgTx. No effect of LEMS sera or IgG on 45Ca2+ uptake was apparent in either preparation.

• Authors: N Martin-Moutot, B Lang, J Newsom-Davis, M Seagar
• Journal: Neuroscience letters (Neurosci Lett) Vol. 187 Issue 2 Pg. 115-8 (Mar 03 1995) ISSN: 0304-3940 [Print] Ireland
• PMID: 7783957 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Calcium Channel Blockers
• Calcium Channels
• Immunoglobulin G
• Nerve Tissue Proteins
• Peptides
• omega-Conotoxin GVIA
• Calcium

Topics

• Animals
• Blotting, Western
• Calcium (metabolism)
• Calcium Channel Blockers (pharmacology)
• Calcium Channels (metabolism)
• Chickens
• Humans
• Immunoglobulin G (metabolism)
• Lambert-Eaton Myasthenic Syndrome (blood)
• Nerve Tissue Proteins (metabolism)
• Peptides (pharmacology)
• Precipitin Tests
• Rats
• Synaptosomes (metabolism)
• omega-Conotoxin GVIA