At the Synaptic Level…
Alcohol affects the brain by altering the neurotransmission of Glutamate, GABA, and endogenous opioids.
![Structure of ethanol (alcohol).](http://sites.lafayette.edu/neur401-02-sp15/files/2015/05/ethanol.jpg)
Glutamate:
-Glutamate (Glu) is the primary excitatory NT in the CNS.
![Structure of glutamate.](http://sites.lafayette.edu/neur401-02-sp15/files/2015/05/Glutamate.jpg)
-Upon acute exposure, ethanol non-competitively inhibits glutamatergic neurotransmission through NMDA/AMPA receptors.
![EtOH&GluBetter](http://sites.lafayette.edu/neur401-02-sp15/files/2015/04/EtOHGluBetter-214x300.jpg)
-After chronic use, neurons upregulate Glu receptors to attempt to maintain normal receptor activity even in the presence of ethanol.
![Glu upreg](http://sites.lafayette.edu/neur401-02-sp15/files/2015/04/Glu-upreg-218x300.jpg)
GABA:
-GABA is the primary inhibitory NT in the CNS.
![Structure of GABA.](http://sites.lafayette.edu/neur401-02-sp15/files/2015/05/GABA.jpg)
-Upon acute exposure, ethanol indirectly enhances GABAergic neurotransmission through an unknown mechanism of action, although indirect binding to the GABA receptor and phosphorylation cascades have been suggested.
![EtOH&GABA](http://sites.lafayette.edu/neur401-02-sp15/files/2015/04/EtOHGABA-223x300.jpg)
Opioids:
-Ethanol increases the release of Beta-endorphin from the pituitary and hypothalamus
![Structure of Beta-endorphin.](http://sites.lafayette.edu/neur401-02-sp15/files/2015/05/Beta-endorphin-300x109.png)
-This endogenous opioid acts on the opioid mu-receptors of GABAergic neurons and directly inhibits GABAergic neurotransmission.
![Red circles represent GABA. Blue cirlce represents beta-endorphin.](http://sites.lafayette.edu/neur401-02-sp15/files/2015/05/GABA-Beta-234x300.jpg)