within 24 hours, while the cocaine-mediated inhibition needs more time to be fully established. Ethanol also blocks LTP(GABA), an effect that is reversed by naloxone, a mu-opioid receptor (MOR) antagonist (Guan and Ye, 2010), suggesting that ethanol may exert its block via the opioid system. To understand the consequences of LTP(GABA) inhibition on mesolimbic DA circuitry it will be important to determine the precise connectivity of GABAergic neurons and which specific inputs are being modulated. VTA DA neurons receive inhibitory input from medium spiny neurons of the NAc, the rostromedial tegmental nucleus (RMTg) as well as from interneurons within the VTA, which themselves receive projections form the NAc.
