GENERAL HISTOLOGY

Detailed explanation-1: -Dopamine synthesis begins with the amino acid phenylalanine, and proceeds sequentially through tyrosine, DOPA, and then dopamine. Tyrosine hydroxylase is the rate-limiting enzyme in this pathway. Another important enzyme is DOPA decarboxylase, which decarboxylates DOPA to form dopamine.

Detailed explanation-2: -Tyrosine is the precursor of the catecholamines, converted to dopamine via L-Dopa and the enzymes tyrosine hydroxylase (TH) and aromatic l-amino acid decarboxylase and to noradrenaline by dopamine -hydroxylase (Molinoff and Axelrod, 1971).

Detailed explanation-3: -Dopamine(DA), the most widely distributed in the nervous system and functionally important chemical signal, is synthesized in DA-ergic neurons from L-tyrosine by means of two enzymes, tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC).

Detailed explanation-4: -Norepinephrine is synthesized in neurons starting with the amino acid tyrosine, which is obtained from the diet and can also be synthesized from phenylalanine. Tyrosine is converted to dihydroxyphenylalanine (DOPA) by the enzyme tyrosine hydroxylase; DOPA in turn is converted to dopamine in the cytoplasm.

Detailed explanation-5: -Once L-Tyrosine is produced it then goes to the brain. It crosses over into the brain through something called the large neural amino acid transporter, which moves L-Tyrosine to the brain where it is then converted to dopamine.