Autonomic NS 3 Flashcards
Tyrosine hydroxylase
– Rate limiting step
- inhibited by catecholamines
DOPA decarboxylase
– Methyldopa
hypertension in pregnancy
Dopamine β-hydroxylase (DBH)
– Membrane bound
PNMT
- mainly located in adrenal medulla
- induced by adrenal cortex hormones
Noradrenaline (NA) release
this is facilitated by ca2+
α2 adrenoreceptors on the presynaptic terminal
– ↓Ca2+influx therefore ↓NArelease
norepinephrine transporter
NET
“repackaged” by vesicular monoamine transporter
VMAT
what is noradrenaline uptake and degradation affected by
indirectly acting sympathomimetic drugs
monamine oxidase (MOA) inhibitors
Uptake inhibitors
Drugs that affect catecholamine synthesis
methyldopa
Drugs that affect catecholamine release
- Indirectly acting sympathomimetics – e.g. amphetamines
- By acting on α2 adrenoreceptors – e.g. clonidine
Inhibitors of catecholamine uptake
NET inhibitors – e.g. cocaine, tricylic antidepressants
Inhibitors of catecholamine metabolic degradation
Monoamine oxidase inhibitors used in depression
What are the two main groups of adrenoreceptors
alpha 1 and 2
beta 1, 2 and 3
Adrenergic receptors are
metabotropic (G-protein coupled receptors)
