Related Experiment Video
Updated: Aug 18, 2026

Functional Characterization of Individual Pre- and Postsynaptic Partners In the Drosophila Larval Central Nervous System Using CaMPARI
Published on: June 16, 2026
Endocannabinoid signaling depends on the spatial pattern of synapse activation
Païkan Marcaggi1, David Attwell
1Department of Physiology, University College London, Gower Street, London, WC1E 6BT, UK. P.Marcaggi@ucl.ac.uk
Abstract:
The brain's endocannabinoid retrograde messenger system decreases presynaptic transmitter release, but its physiological function is uncertain. We show that endocannabinoid signaling is absent when spatially dispersed synapses are activated on rodent cerebellar Purkinje cells but that it reduces presynaptic glutamate release when nearby synapses are active. This switching of signaling according to the spatial pattern of activity is controlled by postsynaptic type I metabotropic glutamate receptors, which are activated disproportionately when glutamate spillover between synapses produces synaptic crosstalk. When spatially distributed synapses are activated, endocannabinoid inhibition of transmitter release can be rescued by inhibiting glutamate uptake to increase glutamate spillover. Endocannabinoid signaling initiated by type I metabotropic glutamate receptors is a homeostatic mechanism that detects synaptic crosstalk and downregulates glutamate release in order to promote synaptic independence.
More Related Videos
09:34Applications of Spatio-temporal Mapping and Particle Analysis Techniques to Quantify Intracellular Ca2+ Signaling In Situ
Published on: January 7, 2019
12:06Transmission Electron Microscopy as the Visualization Technique for Analysis of Circadian Synaptic Plasticity in the Mouse Barrel Cortex
Published on: August 19, 2025
Related Concept Videos
Synaptic Signaling
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...
Synaptic Signaling
Interactions Between Signaling Pathways
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
Intracellular Signaling Cascades
Overview of Cell Signaling
Cells respond to many types of information, often through receptor proteins positioned on the membrane. For example, skin cells respond to and transmit touch...
Amplifying Signals via Second Messengers