20 octobre 2012

Biological role of L-DOPA

L-tyrosine by the enzyme tyrosine hydroxylase (TH). It is also the precursor for the monoamine or catecholamine neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). Dopamine is formed by the decarboxylation of L-DOPA. L-DOPA can be directly metabolized by catechol-O-methyl transferase (COMT) to 3-O-methyldopa (3-OMD), and then further to vanillactic acid (VLA). This metabolic pathway is non-existent in the healthy body, but becomes important after peripheral L-DOPA administration in patients with... [Lire la suite]
Posté par tnfalpha à 15:31 - Commentaires [0] - Permalien [#]

20 octobre 2012

Therapeutic use of L-DOPA

L-DOPA crosses the protective blood–brain barrier, whereas dopamine itself cannot. Thus, L-DOPA is used to increase dopamine concentrations in the treatment of Parkinson's disease and dopamine-responsive dystonia. This treatment was originally developed by George Cotzias and his coworkers. Once L-DOPA has entered the central nervous system, it is converted into dopamine by the enzyme aromatic L-amino acid decarboxylase, also known as DOPA decarboxylase (DDC). Pyridoxal phosphate (vitamin B6) is a required cofactor in this reaction,... [Lire la suite]
Posté par tnfalpha à 15:31 - Commentaires [0] - Permalien [#]
20 octobre 2012

L-DOPA

L-DOPA (L-3,4-dihydroxyphenylalanine) is a chemical that is made and used as part of the normal biology of some animals and plants. Some animals including humans make it via biosynthesis from the amino acid L-tyrosine. L-DOPA is the precursor to the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline) collectively known as catecholamines. L-DOPA can be manufactured and in its pure form is sold as a psychoactive drug with the INN levodopa; trade names include Sinemet, Parcopa, Atamet, Stalevo,... [Lire la suite]
Posté par tnfalpha à 15:29 - Commentaires [0] - Permalien [#]