Activity-induced large amplitude postsynaptic mPSPs at soma-soma synapses between Lymnaea neurons

Spontaneous transmitter release has been observed at various synapses that permit analysis at a sufficient resolution as a miniature postsynaptic potential (mPSP). However, the precise mechanisms that regulate spontaneous transmitter release have not yet been fully defined. Activity and ligand‐media...

Full description

Saved in:
Bibliographic Details
Published in:Synapse (New York, N.Y.) N.Y.), 2009-02, Vol.63 (2), p.117-125
Main Authors: Dunn, T.W., McCamphill, P.K., Syed, N.I.
Format: Article
Language:English
Subjects:
acetylcholine
Action Potentials - drug effects
Action Potentials - physiology
Animals
calcium
Lymnaea
Miniature Postsynaptic Potentials - drug effects
Miniature Postsynaptic Potentials - physiology
minis
Neurons - drug effects
Neurons - physiology
Patch-Clamp Techniques
ryanodine
Ryanodine - pharmacology
Synapses - drug effects
Synapses - physiology
synaptic transmission
Synaptic Transmission - physiology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Spontaneous transmitter release has been observed at various synapses that permit analysis at a sufficient resolution as a miniature postsynaptic potential (mPSP). However, the precise mechanisms that regulate spontaneous transmitter release have not yet been fully defined. Activity and ligand‐mediated modulation of large amplitude, spontaneous events significantly enhances postsynaptic excitation in the absence of action potential activity suggesting a more complicated role for this mode of transmitter release, and thus warrants further analysis. Here, we used Lymnaea soma–soma synaptic connections to demonstrate that a transient increase in both the frequency and amplitude of spontaneous events (mPSPs) occurs following a short burst of action potentials in the presynaptic cell. These events were of presynaptic origin and the increase in mPSP amplitude could also be achieved with a stimulatory concentration of ryanodine. Ryanodine also occluded the activity‐induced increase in mPSP amplitude implicating calcium release from these channels in the production of large amplitude spontaneous transmitter release events. This suggests that presynaptic activity triggers ryanodine receptor‐mediated large amplitude minis, indicating that although these events are action potential‐independent, they are nevertheless responsive to the prior activity of the synapse. Synapse 63:117–125, 2009. ©2008 Wiley‐Liss, Inc.
ISSN:0887-4476
1098-2396
DOI:10.1002/syn.20589