Lec 2: Major Central NTs Flashcards
What are the four conditions to consider a chemical messenger a neurotransmitter?
-present in pre-synaptic terminals
-released from pre-synaptic terminal
-when administered into body the effects are identical to the mimicked NT inside body
-should be able to mimic the action of the drug with appropriate affinities and order of potency
list the examples of “small-molecule” NTs
acetylcholine, norepinephrine, dopamine, and serotonin
list the examples of “amino acid” NTs
y-aminobutyric acid/GABA, glutamate, and glycine
list the examples of “neuroactive peptide” NTs
opioid peptides
T/F endocannabinoids are synthesized as needed and stored when not needed
false, not stored
*Memorize NT release, action, inactivation on slide 7
.
T/F ACh is the neurotransmitter at all vertebrate neuromuscular junctions
true
T/F ACH is the NT for all preganglionic neurons, parasympathetic postganglionic neurons, and sympathetic preganglionic neurons
False, only all preganglionic neurons and parasympathetic postganglionic neurons
ACh is used within CNS circuits for what processing?
cognitive processing of attention, learning, memory, and arousal
define a projection neuron
neurons that connect two or more different regions
what is the name of the two projections in the basal forebrain cholinergic
complex that are critical for attention, learning, and memory?
ms medial septal nucleus
bas nucleus basilis
Alzheimer’s is associated with changes in what pathway?
the septo-hippocampal pathway
what drug class can increase the rate of Alzheimer’s? what do they do? examples?
Muscarinic receptor antagonist
disrupt short-term memory
scopolamine and atropine
what two transporters become harder for the neurons to detect due to Alzheimer’s?
ChT and VACht
Which drug class is FDA approved to treat symptoms of Alzheimer’s? Examples?
cholinesterase inhibitors
Galantamine, Rivastigmine, and Donepezil
The Two major Neuronal nicotinic ACh receptor subtypes are?
what do they do?
(a4)2, (B2)3 ->increased cation permeability (Na+, K+)
and
(a7)5 -> increased cation permeability (Ca2+)
what are the three critical components of the SNARE complex and what does it help to control?
Synaptobrevin/VAMP, Syntaxin and SNAP-25
Docking and Fusion of Pre-synaptic Vesicles
what are the three catecholamines used in the brain?
norepinephrine, dopamine, and epinephrine
all catecholamines in the brain are synthesized from?
tyrosine
what contains all machinery for neurotransmitter synthesis, storage and release and are points of synaptic contact (known as swellings along the axon)
varicosities
the catecholamines in the CNS regulate what functions?
arousal, mood, and central regulation of blood pressure
what is the Locus ceruleus?
what does it target?
a nucleus of the brain stem with ascending and descending projections
cerebral cortex, hippocampus, thalamic nuclei, cerebellum and spinal cord
The Locus ceruleus projections to spinal cord are
thought to be important in?
regulation and processing of perceptual information (e.g. pain)
Lateral tegmental noradrenergic neurons: what are the two things it is important for?
arousal and action of antidepressant drugs
what is the rate limiting step of central noradrenergic neurons?
Tyrosine hydroxylase
reuptake at central noradrenergic neurons is carried out via what transporter? what is the result?
NE transporter (NET)
terminates the action of NE in the synapse
Free NE in the presynaptic terminal can be degraded by?
Monoamine oxidase (MAO) and Catechol-o-methyltransferase (COMT)
what are the major subtypes of Central Adrenergic Receptors?
a1, a2, B1, and B2-adrenoreceptors
NE transporter is the main reuptake transporter for what 2 NTs?
serotonin and dopamine
Sympathomimetic (stimulating) effects of cocaine are related to inhibition of what?
NE transporter
The NE transporter is the target for what drug class?
tricyclic antidepressants
what are the functions of dopamine?
motor control, behavior, endocrine responses
Dopaminergic pathways are divided into 3 categories:
-Long
-Intermediate (arcuate nucleus to pituitary): DA is a negative
regulator of prolactin. D2 antagonists increase prolactin
-Short (retina and olfactory bulb)
Name the Two Midbrain Nuclei with Long
Axon Dopaminergic Pathways
Substantia nigra and Ventral tegmental area (VTA)
Information to know about the Substantia nigra:
-Dopamine containing neurons project to the striatum
-This pathway degenerates in Parkinson’s disease
-Led to discovery of therapeutic effects of L-dopa in Parkinson’s
disease
-Side effects of antipsychotic drugs mimic symptoms of
Parkinson’s disease
Information to know about the Ventral tegmental area (VTA):
-Project to the limbic structures and cerebral cortex
-mesolimbic and mesocortical pathways
-Doesn’t degenerate in Parkinson’s disease
- A major limbic structure, the nucleus accumbens, is the reward
center in the brain
-Nucleus accumbens plays an important role as a target for drugs
of abuse (amphetamine and cocaine)
what is the rate limiting step of central dopaminergic neurons?
Tyrosine hydroxylase
reuptake at central dopaminergic neurons is performed by? what is the result?
dopamine transporter (DAT) to terminate the action of DA in the synapse
Free intracellular DA can be degraded by?
Monoamine oxidase (MAO) and Catechol-o-methyltransferase (COMT)
what are the two main metabolites of dopamine?
homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC).
T/F all dopamine receptors are G coupled
True
what are the five subtypes of dopamine receptors?
D1-D5
what does the D1 dopamine receptor subtype do?
which subtype(s) is/are similar to D1?
increase adenylate cyclase through coupling to Gs
D5
what does the D2 dopamine receptor subtype do?
which subtype(s) is/are similar to D2?
decrease adenylate cyclase through coupling to Gi
D3 and D4