Pharmacology for Anaesthesia and Intensive Care

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Section IIICardiovascular drugs

Phenylalanine hydroxylase (mainly in liver)

Tyrosine hydroxylase (rate limiting step)

Dopa decarboxylase

Granulated vesicles

Only within adrenal medulla

Dopamine -hydroxylase

Phenylethanolamine-N-methyltransferase (PNMT)

Actively concentrated in adrenergic

neurones and adrenal medulla

CH 2 — CH 2 — NH 2

HO

Cytoplasm

HO

HO

HO

HO

HO

HO

HO

HO

Phenylalanine

Tyrosine

Dihydroxyphenylalanine

(DOPA)

Dopamine

Noradrenaline

Adrenaline

CH 2 — C — NH 2

H

COOH

—

—

CH 2 — C — NH 2

H

COOH

—

—

CH 2 — C — NH 2

H

COOH

—

—

H

C— CH 2 — NH 2

OH

—

—

CH 3

C— CH 2 — N

OH

H H

—

—

— —

Figure 12.3.Catecholamine synthesis.