CHAPTER 5: CATECHOLAMINES (YOUR
BRAIN ON DRUGS) QUESTIONS AND
CORRECT ANSWERS (100% CORRECT
ANSWERS)
m Dopamine (DA) - Correct answer.Neurotransmitter, related to NE and EPI, that belongs to a group
called catecholamines.
Norepinephrine (NE) - Correct answer.Neurotransmitter related to DA that belongs to a group called
catecholamines. It also functions as a hormone secreted by the chromaffin cells of the adrenal medulla.
Also known as noradrenaline.
Epinephrine (EPI) - Correct answer.Hormone related to NE that belongs to a group called
catecholamines. It is secreted by the chromaffin cells of the adrenal medulla, and it produces the "fight-
or-flight" response by regulating the diversion of energy and blood to muscles. Also known as
adrenaline.
Catecholamines - Correct answer.Group of neurotransmitters and hormones characterized by two
chemical similarities: a core structure of catechol and a nitrogen-containing amine. They belong to a
wider group of transmitters called monoamines or biogenic amines.
Monoamines - Correct answer.Transmitters that possess one amine group.
Biogenic Amine - Correct answer.A transmitter that is made by a living organism and contains at least
one amine group.
Adrenergic - Correct answer.Adjectival form of adrenaline, also called epinephrine (EPI). May be used
broadly to include both NE- and EPI-related features.
Noradrenergic - Correct answer.Adjectival form of noradrenaline (norepinephrine).
, Dopaminergic - Correct answer.Adjectival form of dopamine.
Tyrosine - Correct answer.Amino acid characterized by a phenol group. It is necessary for the synthesis
of the catecholamine neurotransmitters.
Tyrosine Hydroxylase (TH) - Correct answer.Enzyme that catalyzes the conversion of tyrosine to DOPA. It
is the first and rate-limiting step in catecholamine synthesis.
Aromatic Amino Acid Decarboxylase (AADC) - Correct answer.Enzyme that catalyzes the removal of a
carboxyl group from certain amino acids. It is responsible for the conversion of DOPA to DA in
catecholaminergic neurons and the conversion of 5-HTP to 5-HT in serotonergic neurons.
Dopamine β-Hydroxylase (DBH) - Correct answer.Enzyme that catalyzes the third step of NE synthesis in
neurons, the conversion of DA to NE.
Rate-Limiting Enzyme - Correct answer.Enzyme that catalyzes the slowest step in a biochemical pathway.
It determines the overall rate of product formation.
L-DOPA - Correct answer.Precursor necessary for the synthesis of DA. L-DOPA is formed by the addition
of a hydroxyl group to tyrosine by the enzyme TH. It is used to treat Parkinson's disease by increasing DA
formation.
α-Methyl-Para-Tyrosine (AMPT) - Correct answer.Drug that inhibits TH activity, thereby reducing
catecholamine synthesis.
Vesicular Monoamine Transporter (VMAT) - Correct answer.Vesicle membrane protein that transports
monoamines (i.e., catecholamines and 5-HT) into synaptic vesicles. Monoamine neurons express a
particular form of VMAT called VMAT2, whereas the epinephrine- and norepinephrine-secreting
chromaffin cells of the adrenal medulla express a different form called VMAT1.
Reserpine - Correct answer.Drug extracted from Rauwolfia serpentina (snake root) roots. It inhibits
vesicular monoamine uptake by VMAT, thereby reducing monoamine levels in the central and peripheral
nervous system.
BRAIN ON DRUGS) QUESTIONS AND
CORRECT ANSWERS (100% CORRECT
ANSWERS)
m Dopamine (DA) - Correct answer.Neurotransmitter, related to NE and EPI, that belongs to a group
called catecholamines.
Norepinephrine (NE) - Correct answer.Neurotransmitter related to DA that belongs to a group called
catecholamines. It also functions as a hormone secreted by the chromaffin cells of the adrenal medulla.
Also known as noradrenaline.
Epinephrine (EPI) - Correct answer.Hormone related to NE that belongs to a group called
catecholamines. It is secreted by the chromaffin cells of the adrenal medulla, and it produces the "fight-
or-flight" response by regulating the diversion of energy and blood to muscles. Also known as
adrenaline.
Catecholamines - Correct answer.Group of neurotransmitters and hormones characterized by two
chemical similarities: a core structure of catechol and a nitrogen-containing amine. They belong to a
wider group of transmitters called monoamines or biogenic amines.
Monoamines - Correct answer.Transmitters that possess one amine group.
Biogenic Amine - Correct answer.A transmitter that is made by a living organism and contains at least
one amine group.
Adrenergic - Correct answer.Adjectival form of adrenaline, also called epinephrine (EPI). May be used
broadly to include both NE- and EPI-related features.
Noradrenergic - Correct answer.Adjectival form of noradrenaline (norepinephrine).
, Dopaminergic - Correct answer.Adjectival form of dopamine.
Tyrosine - Correct answer.Amino acid characterized by a phenol group. It is necessary for the synthesis
of the catecholamine neurotransmitters.
Tyrosine Hydroxylase (TH) - Correct answer.Enzyme that catalyzes the conversion of tyrosine to DOPA. It
is the first and rate-limiting step in catecholamine synthesis.
Aromatic Amino Acid Decarboxylase (AADC) - Correct answer.Enzyme that catalyzes the removal of a
carboxyl group from certain amino acids. It is responsible for the conversion of DOPA to DA in
catecholaminergic neurons and the conversion of 5-HTP to 5-HT in serotonergic neurons.
Dopamine β-Hydroxylase (DBH) - Correct answer.Enzyme that catalyzes the third step of NE synthesis in
neurons, the conversion of DA to NE.
Rate-Limiting Enzyme - Correct answer.Enzyme that catalyzes the slowest step in a biochemical pathway.
It determines the overall rate of product formation.
L-DOPA - Correct answer.Precursor necessary for the synthesis of DA. L-DOPA is formed by the addition
of a hydroxyl group to tyrosine by the enzyme TH. It is used to treat Parkinson's disease by increasing DA
formation.
α-Methyl-Para-Tyrosine (AMPT) - Correct answer.Drug that inhibits TH activity, thereby reducing
catecholamine synthesis.
Vesicular Monoamine Transporter (VMAT) - Correct answer.Vesicle membrane protein that transports
monoamines (i.e., catecholamines and 5-HT) into synaptic vesicles. Monoamine neurons express a
particular form of VMAT called VMAT2, whereas the epinephrine- and norepinephrine-secreting
chromaffin cells of the adrenal medulla express a different form called VMAT1.
Reserpine - Correct answer.Drug extracted from Rauwolfia serpentina (snake root) roots. It inhibits
vesicular monoamine uptake by VMAT, thereby reducing monoamine levels in the central and peripheral
nervous system.
