Modulation of acetylcholine receptor channel by a polar component isolated from toxic Ostreopsis lenticularis extracts
Escalona De Motta, G.; Mercado, J.A.; Tosteson, T.R.; González, I.; Lasalde, J.A.
Bulletin de la Societe de Pathologie Exotique 85(5 Part 2): 489-493
1992
ISSN/ISBN: 0037-9085 PMID: 1285088 Document Number: 395753
Methanol extracts obtained from O. lenticularis clones are toxic to mice and inhibit acetylcholine-induced contractions in frog skeletal muscle. Chromatographic fractionation of extracts produced two major fractions with different retention times. Single channel recordings in myocyte membrane patches exposed to more polar fraction showed the appearance of acetylcholine-activated channels whose mean current amplitude was nearly half that of the controls. Channel open times under control and experimental conditions were similar. Thus, this dinoflagellate fraction reduces the ionic conductance of nicotinic receptor channels without altering their lifetime.