Aromatic L-amino acid decarboxylase inhibitors

Aromatic L-amino acid decarboxylase (AADC) inhibitors are a class of drugs that inhibit the enzyme aromatic L-amino acid decarboxylase, also known as DOPA decarboxylase. This enzyme is crucial in the biosynthesis of neurotransmitters, specifically in the conversion of L-DOPA to dopamine, and 5-hydroxytryptophan (5-HTP) to serotonin. By inhibiting this enzyme, AADC inhibitors can affect the levels of these neurotransmitters in the brain and other parts of the body, making them useful in the treatment of various neurological and psychiatric disorders.

Mechanism of Action

AADC inhibitors work by binding to the AADC enzyme, preventing it from converting L-DOPA into dopamine and 5-HTP into serotonin. This action can be beneficial in conditions where there is an overproduction of these neurotransmitters or when a reduction in their synthesis can lead to therapeutic effects. The inhibition of AADC also means that more L-DOPA and 5-HTP are available for conversion in the central nervous system, which can be particularly useful in the treatment of Parkinson's disease and certain mood disorders.

Clinical Uses

AADC inhibitors have found use in several clinical settings:

• In combination with L-DOPA in the treatment of Parkinson's disease, to increase the availability of L-DOPA in the brain and enhance its effectiveness.
• In the management of certain mood disorders, where modulation of serotonin levels can be beneficial.
• As part of the treatment strategy for some patients with dystonia and other movement disorders, where alterations in neurotransmitter levels can help manage symptoms.

Examples of AADC Inhibitors

Some well-known AADC inhibitors include:

• Carbidopa: Often used in combination with L-DOPA in the management of Parkinson's disease.
• Benserazide: Another drug used in conjunction with L-DOPA for Parkinson's disease, available in some countries outside the United States.

Side Effects

The use of AADC inhibitors can lead to various side effects, primarily due to the altered levels of neurotransmitters. These can include:

• Nausea and vomiting
• Orthostatic hypotension
• Headaches
• Dizziness
• Insomnia or sleep disturbances

Future Directions

Research into AADC inhibitors continues, with the aim of improving their efficacy, reducing side effects, and exploring their use in other neurological and psychiatric disorders. Advances in pharmacology and drug design may lead to the development of new AADC inhibitors with better therapeutic profiles.

See Also

• Neurotransmitter
• Parkinson's disease
• Dopamine
• Serotonin