BASIC MEDICAL NEUROSCIENCE -
GMS 6706-001 - UNIT 1C - SYNAPTIC
TRANSMISSION EXAM QUESTIONS
AND ANSWERS
Categories of NT - Answer-Small-molecule transmitters Neuroactive peptides
gaseous NTs
Neuropeptides - Answer--are relatively large transmitter molecules composed of 3 to
36 amino acids
-usually mediate slow ongoing brain functions
-Examples include substance P and the enkephalins
-all interact with metabotropic receptors
neurotransmitter - Answer--chemical substance that is synthesized in a neuron,
released at a synapse following depolarization of the nerve terminal (usually
dependent on influx of calcium ions), which binds to receptors on the postsynaptic
cell and/or presynaptic terminal to elicit a specific response
Acetylcholine - Answer--produced by cholinergic neurons
-Major player in PNS: role in skeletal muscle movement, as well as in the regulation
of smooth muscle and cardiac muscle
-CNS: believed to be involved in learning, memory, and mood
-first neurotransmitter discovered
-is usually (but not always) an exitatory neurotransmitter
-synthesized from choline and acetyl-coenzyme A through the action of the enzyme
choline acetyltransferase
Glutamate - Answer--small molecule NT (amino acid)
-is the most common neurotransmitter in the brain
-always excitatory, usually due to simple receptors that increase the flow of positive
ions by opening ion-channels
GABA - Answer--small molecule NT (amino acid)
-the major inhibitory neurotransmitter of the brain, occurring in 30-40% of all
synapses (second only to glutamate as a major brain neurotransmitter)
-most highly concentrated in the substantia nigra & globus pallidus nuclei of the
basal ganglia, followed by the hypothalamus, the periaqueductal grey matter
("central grey") and the hippocampus
-GABA concentration in the brain is 200-1000 times greater than that of the
monoamines or acetylcholine
Glycine - Answer--small molecule NT (amino acid)
-the simplest of amino acids, consisting of an amino group and a carboxyl (acidic)
group attached to a carbon atom
, -inhibitory neurotransmitter: when released into a synapse, binds to a receptor which
makes the post-synaptic membrane more permeable to Cl- ion
-hyperpolarizes the membrane, making it less likely to depolarize.
-only in vertebrate animals.
Dopamine - Answer--small molecule NT (biogenic amine)
-also catecholamine
-synthesized from dihydroxyphenylalanine (DOPA)
-primarily an inhibitory neurotransmitter
-produces arousal
Norepinephrine - Answer--small molecule NT (biogenic amine)
-also catecholamine
-synthesized from dopamine by means of the enzyme dopamine beta-hydroxylase
(DBH).
Serotonin - Answer--small molecule NT (biogenic amine)
-first isolated from serum as a substance causing powerful smooth muscle
contraction
-tryptamine with a hydroxyl group at the 5-position
-Only 1-2% of the serotonin in the body is in the brain
-widely distributed in platelets, mast cells, etc.
-no equilibration between body serotonin and brain serotonin — the serotonin in the
brain is independently synthesized from tryptophan transported across the blood-
brain barrier
Histamine - Answer--small molecule NT (biogenic amine)
-like the other biogenic amines is stored in presynaptic vesicles and is released into
the synapse.
-Also like other amine neurotransmitters, binds to transmembrane G-protein coupled
receptors on the post-synaptic neurons to exert its function
Which of the following is not considered a type of synapse?
a. Axoaxonic
b. Axosomatic
c. Dendroaxonic
d. Dendrodendritic - Answer-C
How many neurons are contained within the human brain? - Answer->100 billion
What are the two types of synapses? - Answer-electrical and chemical
Electrical Synapses - Answer--permit passive flow of electricity from one neuron to
another through gap junctions, specialized membrane channels that connect the
cytoplasm of 2 cells
-distinct minority of synapses
-very rapid transmission (<0.1 msec)
-flow can be rectifying (unidirectional) or nonrectifying (bidirectional)
GMS 6706-001 - UNIT 1C - SYNAPTIC
TRANSMISSION EXAM QUESTIONS
AND ANSWERS
Categories of NT - Answer-Small-molecule transmitters Neuroactive peptides
gaseous NTs
Neuropeptides - Answer--are relatively large transmitter molecules composed of 3 to
36 amino acids
-usually mediate slow ongoing brain functions
-Examples include substance P and the enkephalins
-all interact with metabotropic receptors
neurotransmitter - Answer--chemical substance that is synthesized in a neuron,
released at a synapse following depolarization of the nerve terminal (usually
dependent on influx of calcium ions), which binds to receptors on the postsynaptic
cell and/or presynaptic terminal to elicit a specific response
Acetylcholine - Answer--produced by cholinergic neurons
-Major player in PNS: role in skeletal muscle movement, as well as in the regulation
of smooth muscle and cardiac muscle
-CNS: believed to be involved in learning, memory, and mood
-first neurotransmitter discovered
-is usually (but not always) an exitatory neurotransmitter
-synthesized from choline and acetyl-coenzyme A through the action of the enzyme
choline acetyltransferase
Glutamate - Answer--small molecule NT (amino acid)
-is the most common neurotransmitter in the brain
-always excitatory, usually due to simple receptors that increase the flow of positive
ions by opening ion-channels
GABA - Answer--small molecule NT (amino acid)
-the major inhibitory neurotransmitter of the brain, occurring in 30-40% of all
synapses (second only to glutamate as a major brain neurotransmitter)
-most highly concentrated in the substantia nigra & globus pallidus nuclei of the
basal ganglia, followed by the hypothalamus, the periaqueductal grey matter
("central grey") and the hippocampus
-GABA concentration in the brain is 200-1000 times greater than that of the
monoamines or acetylcholine
Glycine - Answer--small molecule NT (amino acid)
-the simplest of amino acids, consisting of an amino group and a carboxyl (acidic)
group attached to a carbon atom
, -inhibitory neurotransmitter: when released into a synapse, binds to a receptor which
makes the post-synaptic membrane more permeable to Cl- ion
-hyperpolarizes the membrane, making it less likely to depolarize.
-only in vertebrate animals.
Dopamine - Answer--small molecule NT (biogenic amine)
-also catecholamine
-synthesized from dihydroxyphenylalanine (DOPA)
-primarily an inhibitory neurotransmitter
-produces arousal
Norepinephrine - Answer--small molecule NT (biogenic amine)
-also catecholamine
-synthesized from dopamine by means of the enzyme dopamine beta-hydroxylase
(DBH).
Serotonin - Answer--small molecule NT (biogenic amine)
-first isolated from serum as a substance causing powerful smooth muscle
contraction
-tryptamine with a hydroxyl group at the 5-position
-Only 1-2% of the serotonin in the body is in the brain
-widely distributed in platelets, mast cells, etc.
-no equilibration between body serotonin and brain serotonin — the serotonin in the
brain is independently synthesized from tryptophan transported across the blood-
brain barrier
Histamine - Answer--small molecule NT (biogenic amine)
-like the other biogenic amines is stored in presynaptic vesicles and is released into
the synapse.
-Also like other amine neurotransmitters, binds to transmembrane G-protein coupled
receptors on the post-synaptic neurons to exert its function
Which of the following is not considered a type of synapse?
a. Axoaxonic
b. Axosomatic
c. Dendroaxonic
d. Dendrodendritic - Answer-C
How many neurons are contained within the human brain? - Answer->100 billion
What are the two types of synapses? - Answer-electrical and chemical
Electrical Synapses - Answer--permit passive flow of electricity from one neuron to
another through gap junctions, specialized membrane channels that connect the
cytoplasm of 2 cells
-distinct minority of synapses
-very rapid transmission (<0.1 msec)
-flow can be rectifying (unidirectional) or nonrectifying (bidirectional)
