What Are Neurotransmitters?

Normal function of the brain is dependent upon the ability of nerves to either excite or inhibit one another. Neurotransmitters are chemical messengers that are released during a nerve impulse to either excite or inhibit nerve function.

Excitatory- in this state neurotransmitters promote the initiation of nerve impulses.

Inhibitory- in this state neurotransmitters inhibit the initiation of nerve impulses

There are many neurotransmitters in the body, all of which work together to regulate motor coordination, behavior, temperature, pain mechanisms, blood flow and many other biochemical and physiological properties. Dopamine is a commonly known neurotransmitter associated with Parkinson’s disease. Dopamine, norepinephrine (noradrenalin) and epinephrine (adrenalin) are a group of neurotransmitters called “catecholamines”. Serotonin is another commonly known neurotransmitter often associated with depression. Neurotransmitters associated with pediatric neurotransmitter diseases include the catecholamines, serotonin, and the inhibitory neurotransmitter gamma-aminobuytric (GABA).

The pathways leading to the metabolism (production), synthesis (building up of), and catabolism (break down) of neurotransmitters are extremely complicated systems. The following are the pathways for the neurotransmitters Dopamine and GABA;

GABA Pathway

When there is a disruption within the neurotransmitter system, it can cause abnormalities with many of the brains essential functions.  In pediatric neurotransmitter diseases children are born with genetic defects that affect the neurotransmitter pathways and the use of the related neurotransmitter. The specific pediatric neurotransmitter disease is determined by where the defect in the pathway occurs. For example in Aromatic L Amino Acid Decarboxylase  (AADC) Deficiency the AADC enzyme is affected  in the dopamine pathway and children cannnot effectively utilize the neurotransmitter dopamine.  Another example is in the GABA related disease Succinic Semialdehyde Dehydrogenase (SSADH)  Deficiency. In this pediatric neurotransmitter disease the enzyme SSADH is affected and children have an accumulation of the inhibitory neurotransmitter GABA.