Catecholamines (Norepinephrine, Epinephrine)

Dr. Morton explains catecholamines, their synthesis, storage, release, receptor binding, and degradation. Catecholamines like dopamine, norepinephrine, and epinephrine are synthesized in a specific order, stored in vesicles, and released into synapses. The video also covers adrenergic receptors and the removal of catecholamines through reuptake, diffusion, and degradation.

What is the basic structure of catecholamines?

• A benzene ring with three hydroxyl groups

• A linear chain of carbon atoms

• A benzene ring with two hydroxyl groups and a side chain amine

• A ring structure with a single hydroxyl group

Which enzyme converts tyrosine into DOPA?

• Tyrosine hydroxylase

• Dopamine beta-hydroxylase

• Phenylethanolamine N-methyltransferase

• DOPA decarboxylase

In which part of the body is epinephrine primarily synthesized?

• Adrenal medulla

• Substantia nigra

• Cerebral cortex

• Thyroid gland

What role do SNARE proteins play in catecholamine release?

• They transport catecholamines into vesicles

• They synthesize catecholamines

• They degrade catecholamines

• They mediate the fusion of vesicles with the membrane

What is the Greek-derived name for the hormone produced by the adrenal gland?

• Noradrenaline

• Norepinephrine

• Adrenaline

• Epinephrine

Which adrenergic receptor type is not mentioned in the video?

• Beta-2

• Alpha-1

• Alpha-2

• Beta-3

What is the primary method of norepinephrine removal from the synaptic cleft?

• Diffusion into the bloodstream

• Reuptake into the adrenergic nerve ending

• Degradation by MAO

• Conversion into dopamine

Which enzyme is responsible for degrading circulating catecholamines?

• Catechol-O-methyltransferase

• Dopamine beta-hydroxylase

• Tyrosine hydroxylase

• DOPA decarboxylase

What percentage of norepinephrine is typically reuptaken into the nerve ending?

• 80% to 100%

• 50% to 80%

• 10% to 30%

• 30% to 50%

How long does epinephrine from the adrenal gland remain active in the bloodstream?

• Several hours

• One to several minutes

• Indefinitely

• A few seconds