Neurons and Neurotransmitters
The functional unit of the brain is the neuron, explains an article in "Alcohol Health and Research World." Neurons are responsible for controlling thoughts, movement, emotions and the functions of vital organs. Neurons do not work in isolation, however. Throughout the brain, each neuron is connected with other neurons via small spaces called synapses. Sometimes, hundreds or thousands of different neurons can be connected to the same synapse. Neurons communicate across synapses through the use of chemical messengers, which are called neurotransmitters. When a neurotransmitter is released into a synapse by a neuron, it can bind to special proteins (called receptors) on the other neurons that participate in the synapse. Depending on the kind of neurotransmitter and the type of receptor, this binding can either excite or inhibit the actions of the other neurons.
Immediate Effects
Alcohol has many effects on neurotransmitter levels. Alcohol binds to receptors for many different neurotransmitters, including serotonin, acetylcholine, GABA and glutamate, according to the Canadian Institutes of Health Research. Alcohol inhibits brain activity, leading to decreased levels of excitatory neurotransmitters and increased levels of inhibitory signals.
Chronic Effects
Although the short-term effects of alcohol consumption are to lower brain activity, over time the brain adapts to the chemical changes of alcohol. The brain naturally adjusts its receptor levels and neurotransmitter output so that normal neurotransmitter levels are maintained with alcohol consumption (also known as tolerance). When the patient stops drinking alcohol, the inhibition (for which the brain had already compensated) is then taken away, leading to a surge in excitatory neurotransmitter levels. This phenomenon is responsible for the symptoms of alcohol withdrawal.
