Brain Chemistry

Serotonin (5-hydroxytryptamine) is an amino acid style neurotransmitter.  Serotonin binds with serotonin receptors. Serotonin binding is linked to mood and sleeping patterns.


The overall effect of this mood transmitter is to promote relaxation and sleepiness.

Serotonin is a calmative transmitter that counters the effects of catecholamines and dopamine.


Serotonin production is concentrated within the neurons of the Raphe nuclei of the brain. Serotonin produces its effect via  second messenger activity that follows initial binding.


Serotonin’s overall effect is inhibition.


Serotonin is formed from the precursor amino acid tryptophan. Tryptophan must cross the blood-brain barrier using what is called the large neutral amino acid transporter. This carrier also transports tyrosine where it is used in the synthesis of catecholamines (epinephrine). Use of this carrier after eating is responsible for the sleepiness that follows eating.



Catecholamines  are also neurotransmitters.  The effect of catecholamines in the brain is stimulatory. Unlike serotonin, catecholamines bind to receptors outside the brain. Here, they are the neurotransmitter of choice for autonomic control.

Inside the brain, catecholamines overall effect is stimulation.

Catecholamines like epinephrine (adrenaline) are synthesized from the amino acid tyrosine while serotonin is derived from the amino acid tryptophan.

Tryptophan and tyrosine both compete for the receptor site on the ‘neutral amino transporter’ to gain entry to the brain. The effect that ultimately develops (relaxation vs activity) is determined by which precursor (tryptophan or tyrosine) has a higher concentration around the carrier’s receptor.

These concentrations are linked to insulin and its ability to remove tryptophan competitors (tyrosine is a competitor) from the blood. Increased tryptophan is the blood, increases the likelihood that the transporter will pair up with tryptophan, leading to higher serotonin levels and the stimulation of serotonin receptors to produce relaxation. That is why certain meals cause sleepiness.

Tryptophan is the most limited amino acid in food. There are  certain foods that contain higher amounts and include dairy and soy products, whole grains and beans as well as meat and fish.


Increasing the level of serotonin is one of the two ways that psychopharmacological drugs work. They are known as SSRI (serotonin-specific re-uptake inhibitors), which block the serotonin pump from ending serotonin activity.

Lack of tryptophan stores in the brain may be responsible for the blackouts suffered during alcohol binges.

Tryptophan and supplements to increase GABA concentrations  are innovative ideas to help alcoholics quit drinking.

Lysergic acid diethylamide (LSD)

Alkaloid compounds can affect the activity of serotonin due to their structural similarity and binding with serotonin receptors.  Lysergic acid diethylamide (LSD), a derivative of morning glory seeds, has been used for centuries in carrying out sacred rituals or casting out evil demons. The mechanism of morning glory seeds and LSD’s hallucinatory action is thought to be the result of an interaction between serotonin receptors and the synapses involved in the visual cortex. The visual perceptions not received through the eyes, such as those experienced while dreaming, appear to originate by serotonin stimulation. LSD binding with serotonin receptors accounts for the hallucinatory state that occurs with LSD


Drugs also operate by binding or interfering with membrane bound receptors. Botanical compounds bind with these receptors to produce their effects.

Most plants contain a library of these compounds, each one capable of binding with a different receptor. The  effect of these bindings is the result of this combination and not solely the result of the predominate compound.

Natural medicine is based on plants.  Whole plants produce conflicting and opposing effects.  This phenomena is best  described as adaptogenic.  These plant compounds are a group of medically effective substances that heightened one’s resistance to stress.

Adaptogenic substances produced different effects depending upon the person it was administered to.

Adaptogens are substances that promote a non-specific increase in resistance against a variety of stressful conditions.


Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the brain. GABA is synthesized in the brain from the amino acid glutamate.  GABA prevents overactivity. Lack of GABA results in anxiety and overactivity.

The GABA receptor is composed of five different subunits of proteins (alpha, beta, gamma, delta, epsilon and pi). The substructure of these subunits determines the sensitivity to various addictive compounds. Each subunit has its own receptor site and is specific for the ligans it accepts

The subunits are assembled to form a membrane pore through which chloride ions flow when the receptor is bound.

GABA receptors bind to drugs like alcohol, benzodiazepines (valium) and barbiturates as well as steroids.

GABA receptor stimulation causes relaxation.  Activities such as movement, memory, reasoning, and respiration are controlled in areas, high in GABA receptors.

More in this category: « Molecular Addiction