title: Fractal behavior of spontaneous neurotransmitter release: from single-synapse to whole-cell recordings.
abstract: Spontaneous release of neurotransmitter vesicles at brain chemical synapses has been deeply investigated in the last decades at several levels. First and second order statistics have been widely adopted as a tool for assessing, inter-alia, dependence of spontaneous release on the concentration of ionic species in the intra- or extra-cellular environment. Furthermore, several studies demonstrated that spontaneous release exhibits fractal, and generally non purely random, behavior. Most experimental work on this topic exploits population whole-cell patch-clamp recordings in order to acquire post-synaptic currents elicited by neurotransmitter release into the synaptic cleft. Since several synapses merge on the dendritic arbor of a single neuronal cell, whole-cell recordings of miniature excitatory post-synaptic currents (mEPSCs) implies the temporal superimposition of releasing events from all active synapses on the arbor. This limitation can be overcome by exploiting the loose-patch clamp technique on single synapses, thus acquiring spontaneous release events from individual synapses. Here, we present results obtained by applying well-established methods for the quantification of fractal behavior in the series of mEPSCs acquired through the use of both whole-cell and single-synapse loose-patch recording techniques on hippocampal neurons and synapses. Our long-term aim is to get a better understanding of the release process and of the mechanisms of neuronal integration when the information is coming from several simultaneously active synaptic sites.
authors.affiliation: Dipartimento di Bioingegneria, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milano, Italy. jacopo.lamanna@mail.polimi.it
authors.forename: Jacopo
authors.initials: J
authors.lastname: Lamanna
authors.forename: Federico
authors.initials: F
authors.lastname: Esposti
authors.forename: Antonio
authors.initials: A
authors.lastname: Malgaroli
authors.forename: Maria G
authors.initials: MG
authors.lastname: Signorini
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D017709:Fractals; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D051381:Rats; D013569:Synapses / Q000378:metabolism*
chemical_list: D018377:Neurotransmitter Agents