Endocannabinoid-dependent long-term depression of GABAergic synaptic transmission in the neocortex
-
1
European Brain Research Institute (EBRI), Department of Signal Processing, Italy
-
2
Neurocentre Magendie, INSERM, France
Endocannabinoids (ECs) are endogenous lipids that retrogradely regulate presynaptic release of neurotransmitter. Moreover, we have shown that autocrine actions of ECs result in a persistent depression of excitability (slow self-inhibition, or SSI) in several neocortical neurons, including ~30% of layer 2/3 pyramidal neurons (PNs). Here we show that these pre- and postsynaptic EC-mediated actions coexist and interact in neocortical PNs. Indeed, SSI-inducing repeated depolarizations elicited a persistent reduction of GABAergic transmission in all SSI+, but in much smaller percentage of SSI- PNs. This form of depolarization-induced long-term depression of inhibition (d-LTDi) was terminated by late applications of AM-251, suggesting a persistent activation of presynaptic CB1 receptors. d-LTDi differs from other forms of EC-mediated GABAergic synaptic plasticity, in which CB1Rs were necessary for the induction but not expression of long-term changes of synaptic inhibition. Moreover, d-LTDi in layer 2/3 PNs was induced by postsynaptic depolarizations alone, thus excluding heterosynaptic plasticity. Thus, ECs can differentially regulate the activity of neocortical PNs upon depolarizations: a decrease of PN activity through autocrine SSI, and a retrograde disinhibition of the same neurons. Such dualistic effects could play important roles in the modulation of neocortical excitatory networks.
Conference:
EMBO workshop: Gaba Signalling and Brain Networks , Amsterdam, Netherlands, 30 Jun - 2 Jul, 2010.
Presentation Type:
Poster Presentation
Topic:
Posters
Citation:
Bacci
A,
Cannich
A,
Marinelli
S,
Marsicano
G and
Pacioni
S
(2010). Endocannabinoid-dependent long-term depression of GABAergic synaptic transmission in the neocortex.
Conference Abstract:
EMBO workshop: Gaba Signalling and Brain Networks .
doi: 10.3389/conf.fnins.2010.15.00002
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
22 Jun 2010;
Published Online:
22 Jun 2010.
*
Correspondence:
A. Bacci, European Brain Research Institute (EBRI), Department of Signal Processing, Rome, Italy, alberto.bacci@icm-institute.org