Norepinephrine Flashcards
What is the synthesis of norepinephrine?
L-tyrosine —–>
TH
L-dopa————————–>
DOPA decarboxylase
dopamine———-> norepinephrine
DBH
What are the major metabolic end-products from catecholamine breakdown?
VMA (vanillylmandelic acid) and MHPG
How can the levels of MHPG in the CSF or VMA be assessed by the catabolism of catecholamines?
through the urine
True or false: breakdown of NE can only occur at the synapse
False, can occur both at the synapse or the presynaptic cell
Fill in the blank: After the release, NE is recycled into the cell by ________
NE transporter
True or false: NE is catabolized by MOA and COMT or recycled through VMAT
true
What receptor does norepinephrine bind to and activate?
Adrenergic receptors (and the metabotropic-> g-protein coupled receptors)
What is the adrenergic receptor responsible for and what does it function as?
Responsible for both CNS effects and peripheral
Functions as post-synaptic receptor and as presynaptic autoreceptor
Agonists and antagonists are adrenergic receptors of what systems?
Sympathomimetic and sympatholytic, respectively
What is a1 and a2 coupled to and what is phenylephrine?
A1- coupled to Gqa, modulate
A2- coupled to Gia, inhibit
Phenylephrine is a selective agonist (a1/2- which modulates and inhibits)
True or false: alpha-adrenergic receptors are responsible for vasoconstriction and are found in the brainstem (vasomotor centre) and are known as autoreceptors
true
What can agonist at a2 receptor do?
Lower blood pressure- CNS acting
What is clonidine prescribed to treat and what do the side effects include?
To treat hypertension and includes sedation and drowsiness
True or false: a-adrenergic receptors are also effective treatment for ASD by increasing NE in the PFC at postsynaptic a2a receptor
False, effective for ADHD
B1,b2,b3 are coupled to and what is isoprenaline?
B1 coupled to Gsa
B2 mostly coupled…
B3 coupled…
Iso is a selective agonist (B1/2/3)
True or false: B-adrenergic is responsible for vasodilation
true
What do agonist b-adrenergic receptors do?
Relax bronchial muscles