Page 22 - pharma 1 theoretical updated MNU_Neat

Clinical pharmacy 2024/2025 Level 3 Pharm D Pharmacology 1 (PO 502)

1. Epinephrine

1) Phenylalanine ➔ Ph. Alanine hydroxylase ➔ Tyrosine
Synthesis of epinephrine 3) Dopa ➔ Dopa decarboxylase ➔ Dopamine
2) Tyrosine ➔ Tyrosine hydroxylase ➔ Dopa

4) Dopamine ➔ Dopamine β Hydroxylase ➔ Norepinephrine
NE ➔ Phenyl Ethanolamine N-Methyltransferase ➔ Epinephrine

If enzyme  ➔ no Tyrosine & PKU →Mental retard
 methyl tyrosine,  Me NE, ME dopamine ➔ all are false neurotransmitter

→  NE → B. P
➢ Bound E in granules with ATP and protein.
Stored in 3 forms ➢ Free E in granules not bound or loosely bound to ATP and released by

nerve stimulation.
➢ Cytoplasmic (non-vesicular) free E within the cytoplasm→ released by
indirect sympatho-mimetics.

1. Neuronal uptake “Amino pump” (uptake I) → actively transports
E into the neuronal cytoplasm.
Reuptake:
2. Granular uptake → actively transports cytoplasmic E into the
Fates of Epinephrine 3. Non-neuronal uptake (uptake II) → E is taken into muscle and
storage vesicles.

gland prior to destruction.

1) Catechol-O-methyl transferase (COMT): distributed in liver,
catabolism:
kidney, intestine but, not found in nerve endings.
Enzymatic
2) Monoamine oxidase (MAO): distributed in the brain, liver, kidney
and in the mitochondria of adrenergic neurons.
MAO-A → peripheral tissues, metabolizes all monoamines, &
MAO-B → brain and does not metabolize E or NE.

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