LECTURE 4

Question 1

How does the presynaptic membrane deliver information?

Answer 1

neurotransmitters

Question 2

How does the postsynaptic membrane receive information?

Answer 2

receptors for neurotransmitters

Question 3

What is a synapse?

Answer 3

is the primary location of neural communication with another cell

Question 4

What is chemical synaptic transmission?

Answer 4

Release of a chemical at a synapse whereby by one cell influences another

Question 5

What are the steps to create a synaptic potential?

Answer 5

Action potential arrives at the presynaptic terminal

Membrane of the presynaptic terminal depolarizes, opening Ca2+ channels

Influx of Ca2+ into the neuron terminal, combined with the liberation of Ca2+ from intracellular stores, triggers the movement of synaptic vesicles toward a release site in the membrane

Synaptic vesicles fuse with the membrane and release neurotransmitter into the cleft
Neurotransmitter diffuses across the synaptic cleft

Neurotransmitter contacts a receptor on the postsynaptic membrane and binds to that receptor

Binding causes receptor to change shape

Question 6

What does altered configuration of the receptor do?

Answer 6

Opens an ion channel associated with the membrane receptor (Ligand-gated channels)
Activates intracellular messengers associated with the membrane receptor

Question 7

When does presynaptic inhibition or facilitation occur?

Answer 7

if synapse is axoaxonic

Question 8

what is local depolarization?

Answer 8

excitatory postsynaptic potential (EPSP)

Question 9

what is local hyperpolarization?

Answer 9

inhibitory postsynaptic potential (IPSP)

Question 10

In IPSP what channels open and what occurs?

Answer 10

cl and k channels open, hyperpolarization occurs

Question 11

in EPSP what channels open and what occurs?

Answer 11

ca and na channels open, depolarization occurs

Question 12

What is presynaptic facilitation?

Answer 12

occurs when neurotransmitter binding causes local depolarization of the postsynaptic axon terminal resulting in increased release of neurotransmitter

Question 13

What is presynaptic inhibition?

Answer 13

occurs when neurotransmitter binding causes hyperpolarization of the postsynaptic axon terminal resulting in decreased release of neurotransmitter

Question 14

What are three ways to remove neurotransmitters from the synaptic cleft?

Answer 14

neurotransmitter transporters, enzymatic degradation, uptake by glial cells

Question 15

What is spatial summation?

Answer 15

many different synapses must produce EPSPs simultaneously at different locations in the membrane of the postsynaptic cell.

Question 16

What is temporal summation?

Answer 16

summation of EPSPs in response to stimuli that occur at the same location in the membrane of the postsynaptic cell but at different times in rapid succession.

Question 17

where are neuromodulators released and what do they adjust?

Answer 17

released into extracellular fluid and adjust activity of many neutrons.

Question 18

where are neurotransmitters released and what effect do they have?

Answer 18

are released into synaptic cleft, Act directly on postsynaptic ion channels or indirectly activate proteins inside the postsynaptic neuron

Question 19

what is ionotropic?

Answer 19

neurotransmitters that activate ion channels directly, fast

Question 20

what is metabotropic?

Answer 20

neurotransmitters that activate proteins inside the postsynaptic neuron indirectly, slow

Question 21

What is substance P?

Answer 21

common neuropeptide, stimulates nerve endings at site of injury and then in the CNS.

Question 22

What three mechanisms are used to transduce signals in postsynaptic receptors?

Answer 22

Directly open ion channels, indirectly open ion channels, indirectly activate a cascade of intracellular events.

Question 23

What does the release of G protein do?

Answer 23

binds to specific ion channels resulting in their opening

Question 24

In the second-messenger system activation of receptors will?

Answer 24

Activate genes, resulting in changes in quantities of neurotransmitters and receptors
Open ion channels
Regulate intracellular Ca2+ concentrations (cell metabolism)

Question 25

what are agonist?

Answer 25

are drugs that bind to a receptor and mimic the effect of naturally occurring neurotransmitters

Question 26

what are antagonist?

Answer 26

are drugs that prevent the release of neurotransmitters or bind to the receptor and impede or block the naturally occurring transmitter

Question 27

What is myasthenia gravis?

Answer 27

Disease in which antibodies attack and destroy nicotinic receptors on muscle cells

Question 28

What is acetylcholine?

Answer 28

major neurotransmitter of PNS, 2 types.
Nicotinic- ionotropic excitatory at NMJ.
Muscarinic- metabotropic, excitatory or inhibitory

Question 29

what is glutamate?

Answer 29

Main excitatory neurotransmitter of CNS
Ionotropic or metabotropic
Involved in long term potentiation which is important in learning and development

Question 30

What is GABA?

Answer 30

Most common fast-acting inhibitory neurotransmitter
GABA binds to two different receptors

GABAA: ionotropic Cl- channels producing hyperpolarization
Drugs inhibit neuronal excitation
GABAB : slow acting receptors linked to ion channels via second messenger

Question 31

What are opioids?

Answer 31

Inhibit neurons in CNS that involved in the perception of pain

Question 32

What is dopamine?

Answer 32

Slow-acting inhibitory neurotransmitter which suppresses Ca2+ channels
Drugs acting on dopamine receptors alter movement, motivation and thinking

Question 33

What is norepinephrine?

Answer 33

Involved in “Flight or Fight” response
Excessive levels in panic disorders
G-protein-mediated inhibitory and excitatory
Two major subtypes:
Α receptors (inhibitory)– Relaxation of smooth muscle
Β receptors (excitatory) – contraction of cardiac muscle (ex. Beta blockers)

Question 34

What is serotonin?

Answer 34

Responsible for general arousal level
Affects mood, perception of pain, arousal levels
High levels: Alertness,
Low levels: REM sleep, depression, suicide