Only a few neurons in the central nervous system use epinephrine. These are located together with noradre-nergic cells in the medulla oblongata, solitary tract nucleus, and medial longitudinal fascicle.

As we have seen, the synthesis of epinephrine is carried out in four enzymatic steps, the first two being common to dopamine, NE, and epinephrine, the first three being common to NE, and epinephrine, and the last needed only for the synthesis of epinephrine. Why are NE and epinephrine not made in dopaminergic neurons? The particular neurotrans-mitter produced is determined by the absence of the next enzyme. Thus, no products past dopamine are produced in dopaminergic neurons because dopa-mine b-hydroxylase is absent. Similarly, epinephrine is not produced in neurons that lack the methyl-transferase.

d. Serotonin (5-HT), an Indoleamine The essential amino acid L-tryptophan is oxidized to 5-hydroxy-tryptophan (5-HTP) by tryptophan hydroxylase, an enzyme homologous to tyrosine hydroxylase. The amino acid decarboxylase that operates in the cate-cholamine pathway also decarboxylates 5-HTP to serotonin.

Conquering Fear In The 21th Century

Conquering Fear In The 21th Century

The Ultimate Guide To Overcoming Fear And Getting Breakthroughs. Fear is without doubt among the strongest and most influential emotional responses we have, and it may act as both a protective and destructive force depending upon the situation.

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