Question 1

What is kiss-and-run exocytosis?

Accepted Answer

A)  Vesicle pore formation with the plasma membrane followed by full vesicle fusion 
B)  Vesicles dock with the plasma membrane, but then undock before releasing transmitter 
C)  Vesicle membrane remains part of the plasma membrane after exocytosis 
D)  Vesicle pore formation with the plasma membrane that is not followed by full vesicle fusion, but rather by closure of the pore 
E)  A form of exocytosis that does not release any neurotransmitter 
A)  Vesicle pore formation with the plasma membrane followed by full vesicle fusion 
B)  Vesicles dock with the plasma membrane, but then undock before releasing transmitter 
C)  Vesicle membrane remains part of the plasma membrane after exocytosis 
D)  Vesicle pore formation with the plasma membrane that is not followed by full vesicle fusion, but rather by closure of the pore 
E)  A form of exocytosis that does not release any neurotransmitter D

Question 2

At the frog NMJ, why does lowering the extracellular calcium and adding extracellular magnesium not only reduces the amplitude of EPPs on average, but also leads to the occasional failure of the nerve terminal to release transmitter after nerve stimulation?

Accepted Answer

A)  Occasionally the nerve terminal fails to trigger an action potential after nerve stimulation. 
B)  The reduced calcium and increased magnesium reduces the probability of transmitter release so much that occasionally there is a statistical chance of failure to release any transmitter. 
C)  The reduced calcium and increased magnesium reduces the probability of transmitter release to zero. 
D)  The reduced calcium and increased magnesium can also block the postsynaptic acetylcholine receptor. 
E)  The reduced calcium and increased magnesium increases the activity of the acetylcholinesterase in the synaptic cleft. 
A)  Occasionally the nerve terminal fails to trigger an action potential after nerve stimulation. 
B)  The reduced calcium and increased magnesium reduces the probability of transmitter release so much that occasionally there is a statistical chance of failure to release any transmitter. 
C)  The reduced calcium and increased magnesium reduces the probability of transmitter release to zero. 
D)  The reduced calcium and increased magnesium can also block the postsynaptic acetylcholine receptor. 
E)  The reduced calcium and increased magnesium increases the activity of the acetylcholinesterase in the synaptic cleft. B

Question 3

What is the experimental evidence that spontaneous miniature end plate potentials (mEPPs) are produced by the release of many molecules of acetylcholine, rather than a single molecule of acetylcholine?

Accepted Answer

Patch electrode recordings demonstrated directly that the amount of current that flows through an individual ACh receptor will produce a potential change in the muscle fiber of approximately 1 μV. Thus, based on the amplitude of mEPPs (about 1.3 mV at the frog NMJ), we can estimate that a mEPP is produced by the opening of about 1300 ACh receptors. In addition, gradually blocking postsynaptic receptors gradually reduced the size of mEPPs, indicated that the potentials were produced by the spontaneous release of discrete amounts of ACh from the nerve terminal and ruled out the possibility that they might be due to single ACh molecules.

Question 4

What synaptic differences do ribbon synapses at retinal photoreceptors possess that allow them to release transmitter in a graded fashion that varies with illumination?

Accepted Answer

To prevent inactivation of calcium chann

Question 5

In which vesicle pool does newly synthesized neurotransmitter become loaded?

Accepted Answer

A)  The reserve pool 
B)  The readily releasable pool 
C)  The extra pool 
D)  The readily releasable pool and the reserve pool 
E)  The recycling pool 
A)  The reserve pool 
B)  The readily releasable pool 
C)  The extra pool 
D)  The readily releasable pool and the reserve pool 
E)  The recycling pool

Question 6

Explain the quantum hypothesis.

Accepted Answer

The quantum hypothesis states that trans

Question 7

What is the concentration of calcium estimated to be in the presynaptic nerve terminal after a brief train of action potentials?

Accepted Answer

A)  100 nM 
B)  1µM 
C)  100 µM 
D)  500 µM 
E)  1 mM 
A)  100 nM 
B)  1µM 
C)  100 µM 
D)  500 µM 
E)  1 mM

Question 8

At a central nervous system neuron that integrates the input from thousands of synapses onto its dendrites, what is the expected average number of quanta released at each synapse?

Accepted Answer

A)  1 
B)  10 
C)  100 
D)  500 
E)  1,000 
A)  1 
B)  10 
C)  100 
D)  500 
E)  1,000

Question 9

What is the definition of quantal size?

Accepted Answer

A)  The number of molecules of transmitter in one quantum 
B)  The number of quanta that are released following a presynaptic action potential 
C)  The number of quanta that are released spontaneously (in the absence of action potentials) 
D)  The total content of transmitter in the presynaptic nerve terminal 
E)  The total number of postsynaptic receptors activated after the release of one synaptic vesicle 
A)  The number of molecules of transmitter in one quantum 
B)  The number of quanta that are released following a presynaptic action potential 
C)  The number of quanta that are released spontaneously (in the absence of action potentials) 
D)  The total content of transmitter in the presynaptic nerve terminal 
E)  The total number of postsynaptic receptors activated after the release of one synaptic vesicle

Question 10

What are the effects of nonquantal release of acetylcholine at the neuromuscular junction?

Accepted Answer

A)  This nonquantal release creates a slow dribble of ACh that has no effects on the postsynaptic muscle cell because it is degraded by acetylcholinesterase. 
B)  This nonquantal release creates a slow dribble of ACh that depolarizes the postsynaptic muscle cell because it escapes being degraded by acetylcholinesterase. 
C)  This nonquantal release creates a large amount of ACh that can cause the postsynaptic muscle cell to fire an action potential. 
D)  This nonquantal release is much less than is released during spontaneous quantal release (mEPPs). 
E)  Nonquantal release does not occur at the neuromuscular junction. 
A)  This nonquantal release creates a slow dribble of ACh that has no effects on the postsynaptic muscle cell because it is degraded by acetylcholinesterase. 
B)  This nonquantal release creates a slow dribble of ACh that depolarizes the postsynaptic muscle cell because it escapes being degraded by acetylcholinesterase. 
C)  This nonquantal release creates a large amount of ACh that can cause the postsynaptic muscle cell to fire an action potential. 
D)  This nonquantal release is much less than is released during spontaneous quantal release (mEPPs). 
E)  Nonquantal release does not occur at the neuromuscular junction.

Question 11

Is the quantum content the same or different at different types of synapses? Provide examples and explanations.

Accepted Answer

The quantum content is very different at

Question 12

When applying statistical methods to analyze transmitter release, what does the term "n" represent in the binomial theory?

Accepted Answer

A)  The number of quanta available for release 
B)  The number of receptors on the postsynaptic membrane 
C)  The number of synapses 
D)  The number of calcium channels that open with each action potential 
E)  The number of number of observations in an experiment 
A)  The number of quanta available for release 
B)  The number of receptors on the postsynaptic membrane 
C)  The number of synapses 
D)  The number of calcium channels that open with each action potential 
E)  The number of number of observations in an experiment

Question 13

At the frog NMJ, after lowering the extracellular calcium and adding extracellular magnesium, how are mEPPs affects?

Accepted Answer

A)  There is no change in mEPPs. 
B)  mEPP amplitude is reduced. 
C)  mEPP amplitude is increased. 
D)  mEPP frequency is reduced. 
E)  mEPP frequency is increased. 
A)  There is no change in mEPPs. 
B)  mEPP amplitude is reduced. 
C)  mEPP amplitude is increased. 
D)  mEPP frequency is reduced. 
E)  mEPP frequency is increased.

Question 14

What is caged calcium, and what can it be used for in studies of the nerve terminal?

Accepted Answer

Caged calcium is a photolabile (sensitiv

Question 15

What is the readily releasable pool of vesicles?

Accepted Answer

A)  Vesicles that are only released during intense prolonged stimulation 
B)  Vesicles that result from recent endocytosis and are re-filled with transmitter 
C)  The first vesicles to be released upon stimulation 
D)  Vesicles that are not depleted rapidly by stimulation 
E)  Vesicles that are never released with action potential stimulation 
A)  Vesicles that are only released during intense prolonged stimulation 
B)  Vesicles that result from recent endocytosis and are re-filled with transmitter 
C)  The first vesicles to be released upon stimulation 
D)  Vesicles that are not depleted rapidly by stimulation 
E)  Vesicles that are never released with action potential stimulation

Question 16

What is the experimental evidence that synaptic vesicles actually fuse with the plasma membrane during transmitter release?

Accepted Answer

The use of the freeze fracture technique

Question 17

Explain how calcium buffers can be used in experiments on the squid giant synapse to provide information about the proximity of calcium channels to the sites of transmitter secretion.

Accepted Answer

If an experimenter compares the effects

Question 18

What is an "active zone"?

Accepted Answer

A collection of proteins at a defined sp

Question 19

What is a microdomain of presynaptic calcium ions?

Accepted Answer

A)  The intracellular calcium ions that fill the presynaptic nerve terminal 
B)  The intracellular calcium ions that are pumped out of the presynaptic nerve terminal 
C)  The intracellular calcium ions that diffuse into the synaptic cleft 
D)  The collected intracellular calcium ions that form around the mouth of a collection of open calcium channels 
E)  The collected intracellular calcium ions that form around the mouth of a single open calcium channel 
A)  The intracellular calcium ions that fill the presynaptic nerve terminal 
B)  The intracellular calcium ions that are pumped out of the presynaptic nerve terminal 
C)  The intracellular calcium ions that diffuse into the synaptic cleft 
D)  The collected intracellular calcium ions that form around the mouth of a collection of open calcium channels 
E)  The collected intracellular calcium ions that form around the mouth of a single open calcium channel

Question 20

What happens to mEPPs when you depolarize the presynaptic nerve terminal membrane by 10-20 mV?

Accepted Answer

A)  There is no change in mEPPs 
B)  mEPPs increase in amplitude. 
C)  mEPPs increase in time course. 
D)  mEPPs increase in amplitude and time course. 
E)  mEPPs increase in frequency. 
A)  There is no change in mEPPs 
B)  mEPPs increase in amplitude. 
C)  mEPPs increase in time course. 
D)  mEPPs increase in amplitude and time course. 
E)  mEPPs increase in frequency.

Exam 13: Release of Neurotransmitters

What is kiss-and-run exocytosis?

At the frog NMJ, why does lowering the extracellular calcium and adding extracellular magnesium not only reduces the amplitude of EPPs on average, but also leads to the occasional failure of the nerve terminal to release transmitter after nerve stimulation?

What is the experimental evidence that spontaneous miniature end plate potentials (mEPPs) are produced by the release of many molecules of acetylcholine, rather than a single molecule of acetylcholine?

What synaptic differences do ribbon synapses at retinal photoreceptors possess that allow them to release transmitter in a graded fashion that varies with illumination?

In which vesicle pool does newly synthesized neurotransmitter become loaded?

Explain the quantum hypothesis.

What is the concentration of calcium estimated to be in the presynaptic nerve terminal after a brief train of action potentials?

At a central nervous system neuron that integrates the input from thousands of synapses onto its dendrites, what is the expected average number of quanta released at each synapse?

What is the definition of quantal size?

What are the effects of nonquantal release of acetylcholine at the neuromuscular junction?

Is the quantum content the same or different at different types of synapses? Provide examples and explanations.

When applying statistical methods to analyze transmitter release, what does the term "n" represent in the binomial theory?

At the frog NMJ, after lowering the extracellular calcium and adding extracellular magnesium, how are mEPPs affects?

What is caged calcium, and what can it be used for in studies of the nerve terminal?

What is the readily releasable pool of vesicles?

What is the experimental evidence that synaptic vesicles actually fuse with the plasma membrane during transmitter release?

Explain how calcium buffers can be used in experiments on the squid giant synapse to provide information about the proximity of calcium channels to the sites of transmitter secretion.

What is an "active zone"?

What is a microdomain of presynaptic calcium ions?

What happens to mEPPs when you depolarize the presynaptic nerve terminal membrane by 10-20 mV?

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

Mechanisms of Direct Synaptic Transmission

Indirect Mechanisms of Synaptic Transmission

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

Filters