Abstract
Resveratrol is a natural phytoalexin synthesized by plants, including grapes. It displays a wide range of neuroprotective benefits associated with anti-aging. Recent studies have shown that resveratrol regulates dopaminergic transmission and behavioral effects of drugs of abuse. The goal of the present study is to investigate whether and how resveratrol alters basal inhibitory synaptic transmission and cocaine-induced inhibitory synaptic plasticity in dopamine neurons of the ventral tegmental area (VTA). We report that resveratrol elevated cAMP levels by itself and further potentiated a forskolin-induced increase in cAMP levels in midbrain slices, consistent with reported effects of inhibition of phosphodiesterases (PDEs). Resveratrol potentiated GABA(A) and GABA(B)-mediated inhibitory postsynaptic currents (IPSCs) in VTA dopamine neurons, and these effects were mediated by a protein kinase A (PKA)-dependent enhancement of presynaptic GABA release. In addition, we found that resveratrol blocked endocannabinoid-mediated long-term synaptic depression in VTA dopamine neurons. Resveratrol pretreatments attenuated cocaine-induced conditioned place preference and blocked the cocaine-induced reduction of GABAergic inhibition in VTA dopamine neurons. Together, these results provide evidence that resveratrol modulates basal inhibitory synaptic transmission, cocaine-induced synaptic plasticity, and drug-cue associative learning.