NAGELHOUT; AUTONOMIC NERVOUS
SYSTEM EXAM QUESTIONS AND
ANSWERS
basic sequence of the synthesis of endogenous catecholamines - ANSWER
Tyrosine converted by tyrosine hydroxylase > Dopa
Dopa converted by aromatic L amino acid decarboxylase > Dopamine
Dopamine converted by Dopamine B hydroxylase > NE
NE converted by phenylethanolamine N methyltransferase > Epi
dietary amino acid that is necessary for catecholamine synthesis - ANSWER
tyrosine
how are catecholamines metabolized? - ANSWER by 2 enzymes
1. COMT (catechol-o-methyltransferase) found in synapse
2. MAO (mono-amine oxidase) found in mitochondria of nerve cells in
(many metabolites formed and some can be used)
forgive the spelling.. i just don't care
review of the PNS and SNS - ANSWER ...
explain the PNS beginning with the parasympathetic nerve - ANSWER 1. long
preganglionic fiber
2. synapse at ganglia
3. The neurotransmitter is ACh
4. nicotinic-cholinergic receptor at the ganglia
5. muscarinic cholinergic receptor post ganglia (at effector tissue)
6. short post ganglionic fiber (ganglia very close to the actual tissue)
explain the SNS beginning with the sympathetic nerve - ANSWER 1. short
preganglionic fiber
2. synapse at ganglia
3. neurotransmitter is ACh pre-synaptic
4. nicotinic cholinergic receptor at ganglia
5. long post ganglionic fiber (ganglia close to the cord)
,6. neurotransmitter is NE post-synaptic
7. adrenergic receptor at effector tissue (can be alpha, beta, or dopa)
in general, the parasympathetic response tends to be ____, and the sympathetic
response tends to be ____, with the exception of the ____ which is ____.
(inhibitory or excitatory) - ANSWER in general, the parasympathetic response
tends to be excitatory, and the sympathetic response tends to be inhibitory, with
the exception of the heart which is excitatory.
explain the negative feedback response for the sympathetic nervous system -
ANSWER catecholamine NE is released from the nerve and typically attaches
to adrenergic receptors at the target tissue = produces sympathetic activity
there is, however, a #2 receptor site on the pre-ganglionic side (autoreceptor)
that causes a negative feedback response mechanism. when NE binds to the pre-
ganglionic receptor it causes sympatholytic effect by controlling/preventing
further NE release
true or false; the parasympathetic and sympathetic nervous systems
communicate by way of epi release - ANSWER false; they communicate by
way of NE release. (when NE release, it can also affect the parasympathetic side
and/or communication with other)
how does precedex/dexmetatomidine work? - ANSWER selectively attaching
to the presynaptic alpha 2 receptors and therefore producing sympatholytic
(negative feedback response) and leading to sedation and decrease in BP
what are the 10 mechanisms by which we can mess with an autonomic nerve -
ANSWER 1. interfere with synthesis of neurotransmitter
2. metabolic transformation by same pathway as precursor of transmitter (false
transmitter)
3. blocking transport system at nerve terminal membrane
4. blocking transport system at storage vesicles
5. promotion of exocytosis or displacement of transmitter from axonal terminal
6. preventing release of transmitter
7. mimicry of transmitter at post-junctional sites
8. blocking post-synaptic receptor
9. inhibition of enzymatic breakdown of transmitter
10. interference with 2nd messenger system
, explain how we could cause mechanism #1
1. interfere with synthesis of neurotransmitter - ANSWER the rate limiting
enzyme for catecholamine synthesis = tyrosine hydroxylase. it converts tyrosine
(essential dieteary amino acid) to Dopa and ...blah blah blah (notecard #1)
if we have a drug that inhibits the enzyme tyrosine hydroxylase then tyrosine
can't be converted to dopa
what kind of overall action will we see if tyrosine hydroxylase is inhibited? -
ANSWER less catecholamine production = sympatholytic response
this is the only tyrosine hydroxylase inhibitor - ANSWER metyrosine
(Demser)
explain how we could cause mechanism #2
2. metabolic transformation by same pathway as precursor of transmitter (we
give a drug that acts like a false transmitter/ give the nerve the wrong thing to
synthesize) - ANSWER giving methyldopa instead of dopa > instead of
making NE, the nerve will make a-methyl-NE instead of NE
giving methyldopa (false transmitter) will make a-methyl-NE instead of NE.
what is a-methyl-NE, what drug is it similar to, and what overall effect will we
see? - ANSWER is an alpha 2 agonist (negative feedback)
similar to clonidine
reduces sympathetic outflow > causes sympatholytic response
explain how we can cause mechanism #3
3. blocking transport system at nerve terminal membrane - ANSWER by
blocking transport at the nerve terminal, you are blocking the reuptake of
neurotransmitter back into the nerve for re-use.
give examples of 2 drugs that are responsible for causing the adrenergic
mechanism #3: blocking transport system at nerve terminal
give example of cholinergic drug and how it works - ANSWER adrenergic:
cocaine and tricyclics (imipramine and amitrptylline used for migraines)
they work by blocking the reuptake of NE back into the nerve
SYSTEM EXAM QUESTIONS AND
ANSWERS
basic sequence of the synthesis of endogenous catecholamines - ANSWER
Tyrosine converted by tyrosine hydroxylase > Dopa
Dopa converted by aromatic L amino acid decarboxylase > Dopamine
Dopamine converted by Dopamine B hydroxylase > NE
NE converted by phenylethanolamine N methyltransferase > Epi
dietary amino acid that is necessary for catecholamine synthesis - ANSWER
tyrosine
how are catecholamines metabolized? - ANSWER by 2 enzymes
1. COMT (catechol-o-methyltransferase) found in synapse
2. MAO (mono-amine oxidase) found in mitochondria of nerve cells in
(many metabolites formed and some can be used)
forgive the spelling.. i just don't care
review of the PNS and SNS - ANSWER ...
explain the PNS beginning with the parasympathetic nerve - ANSWER 1. long
preganglionic fiber
2. synapse at ganglia
3. The neurotransmitter is ACh
4. nicotinic-cholinergic receptor at the ganglia
5. muscarinic cholinergic receptor post ganglia (at effector tissue)
6. short post ganglionic fiber (ganglia very close to the actual tissue)
explain the SNS beginning with the sympathetic nerve - ANSWER 1. short
preganglionic fiber
2. synapse at ganglia
3. neurotransmitter is ACh pre-synaptic
4. nicotinic cholinergic receptor at ganglia
5. long post ganglionic fiber (ganglia close to the cord)
,6. neurotransmitter is NE post-synaptic
7. adrenergic receptor at effector tissue (can be alpha, beta, or dopa)
in general, the parasympathetic response tends to be ____, and the sympathetic
response tends to be ____, with the exception of the ____ which is ____.
(inhibitory or excitatory) - ANSWER in general, the parasympathetic response
tends to be excitatory, and the sympathetic response tends to be inhibitory, with
the exception of the heart which is excitatory.
explain the negative feedback response for the sympathetic nervous system -
ANSWER catecholamine NE is released from the nerve and typically attaches
to adrenergic receptors at the target tissue = produces sympathetic activity
there is, however, a #2 receptor site on the pre-ganglionic side (autoreceptor)
that causes a negative feedback response mechanism. when NE binds to the pre-
ganglionic receptor it causes sympatholytic effect by controlling/preventing
further NE release
true or false; the parasympathetic and sympathetic nervous systems
communicate by way of epi release - ANSWER false; they communicate by
way of NE release. (when NE release, it can also affect the parasympathetic side
and/or communication with other)
how does precedex/dexmetatomidine work? - ANSWER selectively attaching
to the presynaptic alpha 2 receptors and therefore producing sympatholytic
(negative feedback response) and leading to sedation and decrease in BP
what are the 10 mechanisms by which we can mess with an autonomic nerve -
ANSWER 1. interfere with synthesis of neurotransmitter
2. metabolic transformation by same pathway as precursor of transmitter (false
transmitter)
3. blocking transport system at nerve terminal membrane
4. blocking transport system at storage vesicles
5. promotion of exocytosis or displacement of transmitter from axonal terminal
6. preventing release of transmitter
7. mimicry of transmitter at post-junctional sites
8. blocking post-synaptic receptor
9. inhibition of enzymatic breakdown of transmitter
10. interference with 2nd messenger system
, explain how we could cause mechanism #1
1. interfere with synthesis of neurotransmitter - ANSWER the rate limiting
enzyme for catecholamine synthesis = tyrosine hydroxylase. it converts tyrosine
(essential dieteary amino acid) to Dopa and ...blah blah blah (notecard #1)
if we have a drug that inhibits the enzyme tyrosine hydroxylase then tyrosine
can't be converted to dopa
what kind of overall action will we see if tyrosine hydroxylase is inhibited? -
ANSWER less catecholamine production = sympatholytic response
this is the only tyrosine hydroxylase inhibitor - ANSWER metyrosine
(Demser)
explain how we could cause mechanism #2
2. metabolic transformation by same pathway as precursor of transmitter (we
give a drug that acts like a false transmitter/ give the nerve the wrong thing to
synthesize) - ANSWER giving methyldopa instead of dopa > instead of
making NE, the nerve will make a-methyl-NE instead of NE
giving methyldopa (false transmitter) will make a-methyl-NE instead of NE.
what is a-methyl-NE, what drug is it similar to, and what overall effect will we
see? - ANSWER is an alpha 2 agonist (negative feedback)
similar to clonidine
reduces sympathetic outflow > causes sympatholytic response
explain how we can cause mechanism #3
3. blocking transport system at nerve terminal membrane - ANSWER by
blocking transport at the nerve terminal, you are blocking the reuptake of
neurotransmitter back into the nerve for re-use.
give examples of 2 drugs that are responsible for causing the adrenergic
mechanism #3: blocking transport system at nerve terminal
give example of cholinergic drug and how it works - ANSWER adrenergic:
cocaine and tricyclics (imipramine and amitrptylline used for migraines)
they work by blocking the reuptake of NE back into the nerve
