Ethanol can perturb excitatory balance by altering astrocyte calcium signaling and the clearance of neurotransmitters. Ethanol modulates receptor-mediated responses in a pathway specific manner, and may directly increase Ca2+ signaling in a subset of astrocytes. Ethanol also suppresses adenosine-uptake via the astrocytic equilibrative nucleoside transporter 1 (ENT1), leading to increased levels of adenosine and activation of purinergic receptors (A1AR, A2AR, P2XR) resulting in indirect modulation of glutamate and GABA clearence. MR=muscarinic receptor, 5-HTR=serotonin receptor. See text for further details.