Neurotransmitters Flashcards
How is acetylcholine formed?
Acetyl CoA + choline = CoA + ACh
Acetylcholine is recycled by the enzyme ____. What does it do?
acetylcholinesterase.
AChE breaks apart ACh into acetate and choline. Choline is taken back by presynaptic cell and then re-synthesized into ACh in presynaptic cell
Nicotinic receptor is an ___ ___ receptor that is stimulated by ___ and blocked by ____
Nicotinic receptor is an IONOTROPIC ACECTYLCHOLINE receptor that is stimulated by NICOTINE and blocked by CURARE
Muscarinic receptor is a ____ ____ receptor that is stimulated by ___ and inhibited by ____
Muscarinic receptor is a METABOTROPIC ACETYLCHOLINE receptor that is stimulated by MUSCARINE and inhibited by ATROPINE
botulinum toxin
ACh ANTAGONIST, prevents release by terminal buttons
black widow spider venom
triggers release of ACh
hemimcholinium
inhibits uptake of CHOLINE
neostigmine
inhibits the activity of AChE
atropine
drug that blocks MUSCARINIC ACh receptors
Curare
drug that blocks NICOTINIC ACh receptors
2 types of monoamines and their examples
- indolamines: serotonin
2. catecholamines: dopamine, NE, E
What is the precursor of catecholamines?
L-Dopa
Why use L-Dopa for Parkinson’s disease treatment?
because of its effect as a DOPAMINE AGONIST
nigrostriatal system
a dopaminergic system of neurons originating in the SUBSTANTA NIGRA and terminating in the NEOSTRIATUM (caudate nucleus and putanem)
Mesolimbic system
system of dopaminergic neurons originating in the VENTRAL TEGMENTAL AREA and terminating in the NUCLEUS ACCUMBENS, AMYGDALA, and HIPPOCAMPUSA
Mesocortical system
system of dopaminergic neurons originating in the VENTRAL TEGMENTAL AREA and terminating in the PREFRONTAL CORTEX
symptoms of Parkinson’s disease and causes
symptoms: tremors, rigidity of the limbs, poor balance, difficulty initiating movements
causes: DEGENERATION OF NIGROSTRIATAL SYSTEM due to:
- unknown etiology
- viral encephalitis
- brainstem trauma/vascular damage
AMPT
DOPAMINERGIC drug that blocks the activity of tyrosine hydroxylase and thus interferes with the synthesis of catecholamines
tyrosine becomes L-Dopa via:
tyrosine hydroxylase
L-Dopa is decarboxylated to form ____ via ____
L-Dapa is decarboxylated to form DOPAMINE via DOPA DECARBOXYLASE
reserpine
dopaminergic drug that interferes with the storage of monoamines in synaptic vesicles
apomorphine
dopaminergic drug that blocks dopamine autoreceptors at low doses; at higher doses it blocks postsynaptic receptors as well
where are nicotinic receptors usually found?
typically in striated muscle at motor end plate
monoamine oxidase (MAO)
dopaminergic drug
- class of enzyme that destroys monoamines: dopamine, NE, and serotonin
- a drug which inhibits MAO can be used to treat depression, as it would inhibit the breakdown of monoamines
deprenyl (he didn’t talk about in class, but it’s on slides)
dopaminergic drug that blocks the activity of MAO-B; acts as a DOPAMINE AGONIST
chlorpromazine (he didn’t talk about in class, but it’s on slides)
dopaminergic drug that reduces the symptoms of schizophrenia by blocking dopamine D2 receptors
methylphenidate
drug that inhibits the reuptake of dopamine.
Therefore, it is a dopamine agonist, as it causes it to linger in synapse and energize behaviour
Why are receptors needed on the presynaptic membrane?
for negative feedback loop. To inhibit further secretion of dopamine. Activation of these receptors inhibits further release of NTs.
Epinephrine is secreted by the ___ ___
adrenal medulla
Norepinephrine is synthesized in ____
neurons
locus coeruleus
dark-coloured group of noradrenergic cell bodies located in the PONS near the ROSTRAL end of the floor of the FOURTH VENTRICLE
axonal varicosity
enlarged region along the length of an axon that contains synaptic vesicles and releases NTs or neuromodulators
idazoxan
drug that blocks presynaptic noradrenergic alpha-2 receptors and hence acts as an agonist, fascilitating the synthesis and release of NE
Which NT can cross the blood-brain barrier? NE or E?
NE. Epinephrine CANNOT cross BBB
Serotonin is also known as ____
5-hydroxytryptamine (5-HT)
PCPA
drug that inhibits the activity of TRYPTOPHAN HYDROLASE and thus interferes with synthesis of 5-HT