title: Effects of ammodytin L on miniature and endplate potentials in neuromuscular junction of frog m. cutaneus pectoris.
abstract: Neurotoxic effects of ammodytin L (AtnL), a potent phospholipase A2homologue, was studied in frog neuromuscular preparation m. cutaneus pectoris by measuring the influence of the toxin on the amplitude and the frequency of miniature and endplate potentials (MEPPs, EPPs). AtnL, in 100 nM concentration, significantly increases spontaneous quantal acetylcholine release from the motor nerve endings, observed as the increase in MEPPs frequency. At 100 nM or higher concentration the toxin decreases EPPs amplitude and the membrane potential (MP) simultaneously. No significant effect of AtnL on EPPs was observed at any concentration bellow 100 nM. Our results indicate that in frog AtnL shows the typical myotoxic effects, but it also exerts presynaptic effects.
authors.affiliation: Veterinary Faculty,, Ljubljana, Slovenia.
authors.forename: Robert
authors.initials: R
authors.lastname: Frangež
authors.affiliation: Medical Faculty, University of Ljubljana, Slovenia, Slovenia.
authors.forename: Igor
authors.initials: I
authors.lastname: Križaj
authors.affiliation: Medical Faculty, University of Ljubljana, Slovenia, Slovenia.
authors.forename: Franc
authors.initials: F
authors.lastname: Gubenšek
authors.affiliation: Institute "Jožef Stefan", Ljubljana, Slovenia, Slovenia.
authors.forename: Dušan
authors.initials: D
authors.lastname: Šuput
keywords: Key words phospholipase A2; ammodytin L; electrophysiology; frog; m. cutaneus pectoris; neuromuscular preparation