Modulators of catecholamine biosynthesis Flashcards
What are the 2 drugs that modulate catecholamine biosynthesis?
methyl-tyrosine (decr catechol.)
L-Dopa (incr catechol)
What is a similar drug to these, but it doesn’t modulate catecholamine synthesis?
methyl-Dopa
Instead it works by making a false NT that binds at Presynaptic A2 to decr catechol.
What is methyl-tyrosine?
tyrosine hydroxylase inhibitor
one of the modulators of catecholamine biosynthesis
What is the mechanism of action of methyl-tyrosine?
Inhibits tyrosine hydroxylase, decreases production of L-Dopa and thus catecholamines
What condition is treated with methyl-tyrosine?
Pheochromocytoma
What is a potential side effect of methyl-tyrosine?
Hypotension
What is L-Dopa?
A dopamine precursor
one of the modulators of catecholamine biosynthesis
What is the effect of L-Dopa on dopamine production?
Increases amount of L-Dopa available for production of dopamine and catecholamines
What condition is L-Dopa used to treat?
Parkinsonism
Does L-Dopa pass the blood-brain barrier?
Yes
What are some side effects of L-Dopa?
- Dyskinesias
- Nausea
- Orthostatic hypotension
- Psychiatric effects
What is the catecholamine biosynthesis products, down the line?
- Phenylalanine
- tyrosine
- L-dopa
- Dopamine
- norepi
- epi
What is the enzyme order for catechol biosynth?
- phenylalanine hydroxylase
- tyrosine hydroxylase
- L-aromatic amino acid decarboxylase
- dopamine b-hydroxylase
- phenylethanolamine N-methyltransferase (PNMT)
tyrosine hydroxylase is what methyl-tyrosine inhibits
Where does dopamine become NE?
Inside synaptic vesicle
Where does NE become Epi?
chromaffin cell
Where does phenylalanine -> tyrosine -> L-Dopa -> Dopamine?
in axon terminal
