Most neurotransmitters are classified in one of two types – inhibitory and excitatory. Inhibitory neurotransmitters slow down the flow of information by calming and reducing the activity of neurons; they help to bring balance to the body. Excitatory neurotransmitters generally increase the flow of information. It is the balance between the inhibitory and excitatory neurotransmitters that has the greatest effect on your body functions. This post will deal with inhibitory neurotransmitters; we will discuss excitatory neurotransmitters in a future post.
There are several inhibitory neurotransmitters in the body, but the two that are thought to have the greatest and widest reaching effects are serotonin and GABA (gamma amino butyric acid).
Most people know of serotonin in relation to mood and a class of drugs known as selective serotonin reuptake inhibitors (SSRIs) – including Paxil, Prozac, Zoloft, Celexa, Lexapro and Luvox. However, most people do not know that most of the serotonin in the body is produced and found in the intestine (approximately 90%) and the remainder is mostly found in the brain and central nervous system. Serotonin helps to regulate appetite, sleep, memory, learning, temperature, mood, behavior, muscle contraction, cardiovascular function and hormone balance.
GABA is an inhibitory neurotransmitter that helps with reducing anxiety, calming the mind and releasing tension. Some anti-anxiety medications like benzodiazepines (i.e., Xanax, Klonopin, Valium, Lorazepam) and barbiturates (i.e., phenobarbital, Fioricet), as well as many sleep medications (i.e., Ambien, Lunesta) work primarily by increasing the amount of GABA released in a neuron.
Both serotonin and GABA work in conjunction with a specific excitatory neurotransmitter (or group of excitatory neurotransmitters); in this way, they can balance one another to make sure only important signals are sent. Serotonin works in conjunction with a group of excitatory neurotransmitters called the catecholamines; these include dopamine, norepinephrine and epinephrine. GABA works in conjunction with glutamate. The balance between these respective sets of inhibitory and excitatory neurotransmitters is imperative for proper neurotransmitter function.
