Question 1

How does information transfer occur at electrical synapses?

Accepted Answer

A)  Electrical depolarization of the nerve terminal leads to current flow directly from the presynaptic cell to the postsynaptic cell through connexons (or gap junctions). 
B)  Electrical depolarization of the nerve terminal causes presynaptic calcium channels to open, leading to the direct excitation of the postsynaptic cell. 
C)  Electrical depolarization of the nerve terminal causes the release of chemicals that open postsynaptic ligand-gated ion channels which pass current, depolarizing the postsynaptic cell. 
D)  Electrical depolarization of the nerve terminal directly opens postsynaptic ligand-gated ion channels, which pass current, depolarizing the postsynaptic cell. 
E)  Electrical depolarization of the nerve terminal leads to current flow directly from the presynaptic cell to the postsynaptic cell through voltage-gated ion channels. 
A)  Electrical depolarization of the nerve terminal leads to current flow directly from the presynaptic cell to the postsynaptic cell through connexons (or gap junctions). 
B)  Electrical depolarization of the nerve terminal causes presynaptic calcium channels to open, leading to the direct excitation of the postsynaptic cell. 
C)  Electrical depolarization of the nerve terminal causes the release of chemicals that open postsynaptic ligand-gated ion channels which pass current, depolarizing the postsynaptic cell. 
D)  Electrical depolarization of the nerve terminal directly opens postsynaptic ligand-gated ion channels, which pass current, depolarizing the postsynaptic cell. 
E)  Electrical depolarization of the nerve terminal leads to current flow directly from the presynaptic cell to the postsynaptic cell through voltage-gated ion channels. A

Question 2

The NMDA type of glutamate ionotropic receptor requires two agonists to be bound to activate this receptor. What are these two agonists?

Accepted Answer

A)  Glutamate and acetylcholine 
B)  Glutamate and Glycine or D-serine 
C)  Glycine and D-serine 
D)  Glycine and acetylcholine 
E)  D-serine and acetylcholine 
A)  Glutamate and acetylcholine 
B)  Glutamate and Glycine or D-serine 
C)  Glycine and D-serine 
D)  Glycine and acetylcholine 
E)  D-serine and acetylcholine B

Question 3

What determines the decay time for an endplate potential?

Accepted Answer

A)  The time course of acetylcholine release from the nerve terminal 
B)  The time that acetylcholine is present in the synaptic cleft 
C)  The time constant of the presynaptic nerve cell membrane 
D)  The mean open time of the acetylcholine receptor channel 
E)  The time constant of the muscle fiber membrane 
A)  The time course of acetylcholine release from the nerve terminal 
B)  The time that acetylcholine is present in the synaptic cleft 
C)  The time constant of the presynaptic nerve cell membrane 
D)  The mean open time of the acetylcholine receptor channel 
E)  The time constant of the muscle fiber membrane E

Question 4

When electrical synapses are found in the adult CNS, what have they been shown to useful for?

Accepted Answer

Here are two examples. In cortex, electr

Question 5

In adult neurons, activation of ionotropic GABA or glycine receptors results in

Accepted Answer

A)  inward movement of chloride, which leads to hyperpolarization. 
B)  outward movement of chloride, which leads to hyperpolarization. 
C)  inward movement of chloride, which leads to depolarization. 
D)  outward movement of chloride, which leads to depolarization. 
E)  no net movement of chloride, which does not change membrane potential. 
A)  inward movement of chloride, which leads to hyperpolarization. 
B)  outward movement of chloride, which leads to hyperpolarization. 
C)  inward movement of chloride, which leads to depolarization. 
D)  outward movement of chloride, which leads to depolarization. 
E)  no net movement of chloride, which does not change membrane potential.

Question 6

Explain how changes in the developmental expression of different chloride transporters alters the synaptic potential caused by ligand-gated chloride channels that are activated by GABA or Glycine.

Accepted Answer

In embryonic neurons, chloride is transp

Question 7

Following years of debate about chemical vs. electrical transmission at synapses in the brain, which form of transmission was found to exist?

Accepted Answer

A)  All neurons in the brain were found to use electrical transmission. 
B)  All neurons in the brain were found to use chemical transmission. 
C)  Some neurons in the brain were found to use electrical transmission, others chemical transmission, and some both forms of transmission. 
D)  All neurons in the brain were found to initially use chemical transmission, and then convert to electrical transmission. 
E)  All neurons in the brain were found to initially use electrical transmission, and then convert to chemical transmission. 
A)  All neurons in the brain were found to use electrical transmission. 
B)  All neurons in the brain were found to use chemical transmission. 
C)  Some neurons in the brain were found to use electrical transmission, others chemical transmission, and some both forms of transmission. 
D)  All neurons in the brain were found to initially use chemical transmission, and then convert to electrical transmission. 
E)  All neurons in the brain were found to initially use electrical transmission, and then convert to chemical transmission.

Question 8

How many acetylcholine molecules have to bind to the muscle nicotinic acetylcholine receptor to maximally activate this ionotropic receptor channel?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
E)  4 
A)  0 
B)  1 
C)  2 
D)  3 
E)  4

Question 9

What is the reversal potential for a channel?

Accepted Answer

A)  The membrane potential at which the net current flux through a channel is zero, and on either side of which the net current flux moves in opposite directions 
B)  The membrane potential at which the net current flux through a channel is outward 
C)  The membrane potential at which the net current flux through a channel is inward 
D)  The membrane potential of the presynaptic neuron that triggers an action potential 
E)  The membrane potential of the presynaptic neuron that triggers transmitter release 
A)  The membrane potential at which the net current flux through a channel is zero, and on either side of which the net current flux moves in opposite directions 
B)  The membrane potential at which the net current flux through a channel is outward 
C)  The membrane potential at which the net current flux through a channel is inward 
D)  The membrane potential of the presynaptic neuron that triggers an action potential 
E)  The membrane potential of the presynaptic neuron that triggers transmitter release

Question 10

How does acetycholinesterase function at synapses that release acetylcholine?

Accepted Answer

A)  It is a postsynaptic muscarinic receptor blocker. 
B)  It is a postsynaptic nicotinic receptor blocker. 
C)  It is a synaptic cleft enzyme that breaks down acetylcholine receptor proteins. 
D)  It is a presynaptic calcium channel agonist. 
E)  It is a synaptic cleft enzyme that breaks down the transmitter acetylcholine. 
A)  It is a postsynaptic muscarinic receptor blocker. 
B)  It is a postsynaptic nicotinic receptor blocker. 
C)  It is a synaptic cleft enzyme that breaks down acetylcholine receptor proteins. 
D)  It is a presynaptic calcium channel agonist. 
E)  It is a synaptic cleft enzyme that breaks down the transmitter acetylcholine.

Question 11

What happens to the reversal potential for IPSPs when chloride is injected into an adult neuron to increase the cytoplasmic concentration of chloride?

Accepted Answer

A)  The reversal potential does not change. 
B)  The reversal potential becomes more positive. 
C)  The reversal potential becomes more negative. 
D)  The reversal potential is zero millivolts. 
E)  The reversal potential is not affected by the chloride concentration in the cytoplasm. 
A)  The reversal potential does not change. 
B)  The reversal potential becomes more positive. 
C)  The reversal potential becomes more negative. 
D)  The reversal potential is zero millivolts. 
E)  The reversal potential is not affected by the chloride concentration in the cytoplasm.

Question 12

Explain the mechanisms that are used to concentrate acetylcholine receptors on the postsynaptic membrane of motor endplates.

Accepted Answer

The protein Agrin is secreted by motor n

Question 13

When electrical synapses are said to be "rectifying," it means they

Accepted Answer

A)  do not conduct ions in either direction. 
B)  conduct ions equally well in both directions. 
C)  conduct ions more strongly in one direction than the other. 
D)  cause only excitation. 
E)  cause only inhibition. 
A)  do not conduct ions in either direction. 
B)  conduct ions equally well in both directions. 
C)  conduct ions more strongly in one direction than the other. 
D)  cause only excitation. 
E)  cause only inhibition.

Question 14

What would happen to the synaptic potential amplitude caused by an ionotropic receptor in a postsynaptic neuron (e.g. glutamate-mediated EPSP) if the input resistance of the postsynaptic membrane was decreased?

Accepted Answer

A)  There would be no change in the synaptic potential amplitude. 
B)  The synaptic potential would become larger in amplitude. 
C)  The synaptic potential would become smaller in amplitude. 
D)  The synaptic potential would be blocked. 
E)  The synaptic potential would reverse in polarity. 
A)  There would be no change in the synaptic potential amplitude. 
B)  The synaptic potential would become larger in amplitude. 
C)  The synaptic potential would become smaller in amplitude. 
D)  The synaptic potential would be blocked. 
E)  The synaptic potential would reverse in polarity.

Question 15

What is the subunit composition of the NMDA receptor?

Accepted Answer

A)  Four GluN1 subunits arranged as a tetramer 
B)  Four GluN2 subunits arranged as a tetramer 
C)  Two GluN1 subunits and three GluN2 subunits, arranged as a pentamer 
D)  Three GluN1 subunits and two GluN2 subunits, arranged as a pentamer 
E)  Two GluN1 subunits and two GluN2 subunits, arranged as a tetramer 
A)  Four GluN1 subunits arranged as a tetramer 
B)  Four GluN2 subunits arranged as a tetramer 
C)  Two GluN1 subunits and three GluN2 subunits, arranged as a pentamer 
D)  Three GluN1 subunits and two GluN2 subunits, arranged as a pentamer 
E)  Two GluN1 subunits and two GluN2 subunits, arranged as a tetramer

Question 16

Which technique can be used to determine the specific conductance changes in the muscle membrane, and their voltage dependence, after acetylcholine binds to nicotinic receptors?

Accepted Answer

A)  Microelectrode recordings 
B)  Voltage clamp experiments 
C)  Measurement of the movement of radioactive isotopes across the cell membrane 
D)  Fluorescence microscopy 
E)  Gel electrophoresis 
A)  Microelectrode recordings 
B)  Voltage clamp experiments 
C)  Measurement of the movement of radioactive isotopes across the cell membrane 
D)  Fluorescence microscopy 
E)  Gel electrophoresis

Question 17

If you record EPSCs with a patch electrode from an interneuron in the
CA1 region of a rat hippocampal slice preparation and hold the postsynaptic membrane potential at -80 mV, why is the response not sensitive to blockers of NMDA receptors?

Accepted Answer

A)  There are no NMDA receptors at these synapses. 
B)  At -80 mV, AMPA receptors are blocked by magnesium. 
C)  At -80 mV, NMDA receptors do not bind glutamate. 
D)  At -80 mV, NMDA receptors are blocked by magnesium. 
E)  At -80 mV, NMDA receptors do not bind glycine or D-serine. 
A)  There are no NMDA receptors at these synapses. 
B)  At -80 mV, AMPA receptors are blocked by magnesium. 
C)  At -80 mV, NMDA receptors do not bind glutamate. 
D)  At -80 mV, NMDA receptors are blocked by magnesium. 
E)  At -80 mV, NMDA receptors do not bind glycine or D-serine.

Question 18

How does Dopamine modulate electrical coupling in the retina?

Accepted Answer

Light stimulates the release of dopamine

Question 19

How does the size and shape of the endplate potential change when recorded at different distances from the endplate at the NMJ?

Accepted Answer

A)  The EPP does not change when recorded at different distances from the NMJ. 
B)  The EPP has the same amplitude but has a slower time course when recorded at increasing distances from the NMJ. 
C)  The EPP has reduced amplitude but the same time course when recorded at increasing distances from the NMJ. 
D)  The EPP has both a reduced amplitude and slower time course when recorded at increasing distances from the NMJ. 
E)  The EPP has both an increased amplitude and slower time course when recorded at increasing distances from the NMJ. 
A)  The EPP does not change when recorded at different distances from the NMJ. 
B)  The EPP has the same amplitude but has a slower time course when recorded at increasing distances from the NMJ. 
C)  The EPP has reduced amplitude but the same time course when recorded at increasing distances from the NMJ. 
D)  The EPP has both a reduced amplitude and slower time course when recorded at increasing distances from the NMJ. 
E)  The EPP has both an increased amplitude and slower time course when recorded at increasing distances from the NMJ.

Question 20

Which of the following does not exist at a direct chemical synapse?

Accepted Answer

A)  Synaptic vesicles 
B)  30 nm synaptic cleft 
C)  Postsynaptic ligand gated ion channel receptors 
D)  Connexon proteins (gap junctions) 
E)  Active zones 
A)  Synaptic vesicles 
B)  30 nm synaptic cleft 
C)  Postsynaptic ligand gated ion channel receptors 
D)  Connexon proteins (gap junctions) 
E)  Active zones

Exam 11: Mechanisms of Direct Synaptic Transmission

How does information transfer occur at electrical synapses?

The NMDA type of glutamate ionotropic receptor requires two agonists to be bound to activate this receptor. What are these two agonists?

What determines the decay time for an endplate potential?

When electrical synapses are found in the adult CNS, what have they been shown to useful for?

In adult neurons, activation of ionotropic GABA or glycine receptors results in

Explain how changes in the developmental expression of different chloride transporters alters the synaptic potential caused by ligand-gated chloride channels that are activated by GABA or Glycine.

Following years of debate about chemical vs. electrical transmission at synapses in the brain, which form of transmission was found to exist?

How many acetylcholine molecules have to bind to the muscle nicotinic acetylcholine receptor to maximally activate this ionotropic receptor channel?

What is the reversal potential for a channel?

How does acetycholinesterase function at synapses that release acetylcholine?

What happens to the reversal potential for IPSPs when chloride is injected into an adult neuron to increase the cytoplasmic concentration of chloride?

Explain the mechanisms that are used to concentrate acetylcholine receptors on the postsynaptic membrane of motor endplates.

When electrical synapses are said to be "rectifying," it means they

What would happen to the synaptic potential amplitude caused by an ionotropic receptor in a postsynaptic neuron (e.g. glutamate-mediated EPSP) if the input resistance of the postsynaptic membrane was decreased?

What is the subunit composition of the NMDA receptor?

Which technique can be used to determine the specific conductance changes in the muscle membrane, and their voltage dependence, after acetylcholine binds to nicotinic receptors?

If you record EPSCs with a patch electrode from an interneuron in the CA1 region of a rat hippocampal slice preparation and hold the postsynaptic membrane potential at -80 mV, why is the response not sensitive to blockers of NMDA receptors?

How does Dopamine modulate electrical coupling in the retina?

How does the size and shape of the endplate potential change when recorded at different distances from the endplate at the NMJ?

Which of the following does not exist at a direct chemical synapse?

Principles of Signaling and Organization

Signaling in the Visual System

Functional Architecture of the Visual Cortex

Ion Channels and Signaling

Structure of Ion Channels

Ionic Basis of the Resting Potential

Ionic Basis of the Action Potential

Electrical Signaling in Neurons

Ion Transport Across Cell Membranes

Properties and Functions of Neuroglial Cells

Indirect Mechanisms of Synaptic Transmission

Release of Neurotransmitters

Neurotransmitters in the Central Nervous System

Transmitter Synthesis, Storage, Transport, and Inactivation

Synaptic Plasticity

The Molecular and Cellular Biology of Synaptic Plasticity

Mechanisms of Extrasynaptic Communication

Autonomic Nervous System

Walking, Flying, and Swimming: Cellular Mechanisms of Sensorimotor Behavior in Invertebrates

Sensory Transduction

Transduction and Transmission in the Retina

Touch, Pain, and Texture Sensation

Auditory and Vestibular Sensation

Constructing Perception

Initiation and Control of Coordinated Muscular Movements

Development of the Nervous System

Critical Periods in Sensory Systems

Regeneration and Repair of Synaptic Connections After Injury

Appendix

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