The interplay between inflammatory cytokines and the endocannabinoid system in the regulation of synaptic transmission

• IL-1β regulates the synaptic effects of CB1 receptors.
• CB1 receptors regulate TNF-mediated potentiation of excitatory synaptic transmission.
• TRPV1 channels have a permissive role in the synaptic effects of IL-1β.
• Interplay between ECS and inflammatory cytokines controls behavior.
• ECS regulates neurodegenerative processes in multiple sclerosis.

Excessive glutamate-mediated synaptic transmission and secondary excitotoxicity have been proposed as key determinants of neurodegeneration in many neurological diseases.Soluble mediators of inflammation have recently gained attention owing to their ability to enhance glutamate transmission and affect synaptic sensitivity to neurotransmitters. In the complex crosstalk between soluble immunoactive molecules and synapses, the endocannabinoid system (ECS) plays a central role, exerting an indirect neuroprotective action by inhibiting cytokine-dependent synaptic alterations, and a direct neuroprotective effect by limiting glutamate transmission and excitotoxic damage. On the other hand, the endocannabinoid (eCB)-mediated control of synaptic transmission is altered by proinflammatory cytokines with consequent effects in central nervous system (CNS) disorders.In this review, we summarize the interactions, at the pre- and postsynaptic level, between major inflammatory cytokines and the ECS. In addition, the behavioral and clinical consequences of the modulation of synaptic transmission during neuroinflammation are discussed.This article is part of a Special Issue entitled ‘Neuroimmunology and Synaptic Function’.