Test 2: Catecholamines Flashcards
T or F: Small molecule neurotransmitters are proteinaceous
false
T or F: Large molecule neurotransmitters are proteinaceous
true
Which molecule transmitters are synthesized by enzymes with amino acids as precursors?
small molecule
Which molecules transmitters are synthesized from larger precursor proteins and gene products?
large molecule
Which synaptic vesicles package small classical transmitters?
small synaptic vesicles
Which synaptic vesicles package small classical transmitters and co-transmitters that are often neuropeptides?
large synaptic vesicles
Which two ions does neurotransmitter release depend on?
Na and Ca
Receptor in which transmitter receptor is an ion channel, and transmitter binding opens channel
ionotropic
Receptor in which the receptor is not an ion channel but is bound by second messenger pathways to one; transmitter binding opens channel
metabotropic
Dopamine and Norepinephrine are ____
catecholamines
__ and __ share a core structure (catechol group) and a nitrogen containing group (amine) part of a larger group called monoamines or biogenic amines
DA and NE
catecholamine synthesis starts with the amino acid ___
tyrosine
What determines the rate synthesis?
rate limiting step
The rate limiting step in the synthesis of catecholamine is the conversion of __ to __ by ___
tyrosine, DOPA, tyrosine hydroxylase
Tyrosine is converted to DOPA by __
tyrosine hydroxylase
High DA/NE and cell rate of firing [inhibits/excites] tyrosine hydroxylase
inhibits
DOPA is synthesized to dopamine by ___
aromatic amino acid decarboxylase (takes out a carboxyl group)
Dopamine is synthesized to norepinephrine by ___
dopamine B-hydroxylase (adds hydroxyl group on Beta carbon)
Catecholamines are packaged into small classical synaptic vesicles by _____
vesicular monoamine transporter (VMAT)
catecholamine packaging can be blocked by the drug ___
reserpine
Catecholamines are released primarily by __ dependent mechanisms
Ca++
Catecholamine release is inhibited by __ on the synaptic terminal surface, which reduces the amount of __ entering the terminal
auto-receptors, Ca++
Catecholamines can be inactivated by 2 different responses: __ and __
reuptake and metabolism
Reuptake of catecholamines is done by ___ and ___
DA and NE transporters (DATs and NERTs)
Metabolism of catecholamines is done by ___, which transfers a methyl group to catechol ring, and ____ in which oxidization replaces amine
catechol-o-methyltransferase (COMT) and monoamine oxidase (MAO)
Which brain area is implicated in motor function?
substantia nigra
Which brain area is implicated in reward?
ventral tegmental area
DA receptor subtypes (D1-D5) are all [ionotropic/metabotropic]
metabotropic
In __ receptors, transmitter-receptor interaction causes a cascade of structural changes in coupling proteins to occur
slow acting
True or false: all metabotropic receptors use the same coupling protein to initiate sequence of events leading to second messenger production
true
GTP bound alpha subunit of G protein activates ___, which cleaves ATP, creating ___
adenylate cyclase; cAMP
cAMP can induce ___ change in cells
structural
cAMP activates ___ via CREB
gene expression
G protein subunit that activates adenylate cyclase and cAMP production
Gs
G protein subunit that inhibits adenylate cyclase & cAMP production
Gi
Changes in cAMP in cell can affect ___ by altering channel opening/closing
excitability
Normally cAMP acts to close __ channels
K+
___ activates behavior; involved in hunger, pain, anxiety, sex, arousal, and vigilance
norepinephrine
brain area implicated in attention and vigilance
locus coeruleus
Norepinephrine receptor subtypes are [metabotropic/ionotropic]
metabotropic
In general, dopamine [activates, inhibits] behavior
activates
____ can regulate gene transcription and translation due to ___
second messengers; phosphorylations
