The human body uses chemical messengers in the form of neurotransmitters to pass signals between and within our nervous system. Various neurotransmitters jump across the synaptic space between our nerves and other cells (muscles, sensory organs, glands...) in a controlled manner.
The concert of production, transport, release, binding, breakdown and reuptake of various neurotransmitters controls everything from our breathing and heart rate, appetite and digestion, all voluntary and involuntary movements, our reflexes and all five senses.
Neurotransmitter signaling is basically responsible for every corner of our personality: thought patterns, moods, emotions, desires, and the clarity (or distortion) of perceptions. Neurotransmitters also underlie the storage and recollection of all our memories, our dreams, and even allow us to perceive and record our imaginations.
Every day we bootstrap a human personality within the confines of a fantastic human body. Our moods, our personalities, our perceptions and our consciousness are all mediated by the production, passage and binding of fluctuating levels of a variety of neurotransmitters. These tiny molecules are formed and managed by genes, enzymes, hormones, macro-nutrients (protein, fat, carbohydrates), vitamins, minerals, and the body's many interactions with our physical and chemical environment. No part of life as we know it, as animals would be possible without them.
We can exert profound control over our mental-emotional states by modulating our neurotransmitters. For better or worse, we are already well on our way to doing this.
There are at least 50 other neurotransmitters, and we are still discovering more. Here are the primary neurotransmitters:
Dopamine Norepinephrine Adrenaline Serotonin Melatonin Histamine
L-theanine γ-aminobutyric acid (GABA) glutamate aspartate glycine D-serine
Acetylcholine adenosine endorphins anandamide nitric oxide
Here's a real-life example. Caffeine is a competitive inhibitor of the inhibitory neurotransmitter adenosine. When the caffeine we ingest crosses the blood-brain barrier, it competes with adenosine for sites in the postsynaptic adenosine receptors. When caffeine occupies the limited adenosine receptors, it blocks the normal inhibitory effects of adenosine, resulting in greater stimulation of the central nervous system. Only then do we experience the potentially powerful stimulatory effects of caffeine on this single neurotransmitter.
The use of antidepressants and other psychotropic medications (which affect neurotransmitters) has skyrocketed in the last decade. In a recent study, the U.S. Centers for Disease Control and Prevention (CDC) examined 2.4 billion drugs prescribed during doctor and hospital visits in 2005. Of these, antidepressants accounted for 118 million, the most of any drug category. Blood pressure medications were the second most prescribed, with 113 million.
The top 3 systems related to neurotransmitters are:
- Cholinergic system (acetylcholine)
- Serotonergic system (serotonin)
- Dopaminergic system (dopamine)