Endocannabinoid signaling and synaptic plasticity in the brain.

Repetitive firing neuron or activation of synaptic transmission plays an important role in the modulation of synaptic efficacy, such as long-term potentiation (LTP) and long-term depression (LTD). These activity-dependent changes in synaptic efficacy are thought to be critical to learning and memory; however, the underlying mechanisms remain to be defined. Endogenous cannabinoids (eCBs) are diffusible modulators that are released from depolarized postsynaptic neurons and act on presynaptic terminals. Persistent release of eCBs can lead to long-term modulation of synaptic plasticity in the brain. Given a broad distribution of eCB receptors in the brain, the eCB signaling system could contribute to use-dependent modification of brain functions.