Neurotransmitters and Receptors

Question 1

What is the life cycle of a neurotransmitter?

Answer 1

1. Synthesized in the presynaptic cell
2. Stored in synaptic vesicles
3. Released into synaptic cleft following depolarization of presynaptic membrane
4. Diffuses across synaptic cleft
5. Binds to specific receptors on the postsynaptic membrane
6. Removed from synaptic cleft by diffusion, reuptake, or degradation

Question 2

What is the criteria to be a neurotransmitter?

Answer 2

1. Is present in presynaptic neuron
2. Is released in response to presynaptic depolarization
3. Specific receptors are present on postsynaptic cell
4. A mechanism must exist for removing the chemical from its site of action

Question 3

T/F: There are 100 different types of neurotransmitters

Answer 3

False: 200 types

Question 4

What are the main groups of neurotransmitters?

Answer 4

Amino acids, Peptides, and Monoamines

Question 5

What are the two types of receptors?

Answer 5

Ionotropic and Metabotropic

Question 6

What is the advantage of ionotropic receptor?

Answer 6

fast transmission

Question 7

What is the advantage of metabotropic receptor?

Answer 7

amplification

Question 8

What are the methods for identifying neurotransmitters?

Answer 8

1. Histochemical methods
2. Immunohistochemical methods
3. In situ hybridization

Question 9

Where can you find acetylcholine?

Answer 9

1. neuromuscular junction
2. preganglionic neurons of autonomous systems
3. postganglionic neurons of parasympathicus
4. midbrain cortex

Question 10

What synthesizes acetylcholine?

Answer 10

Choline acetyltransferase

Question 11

What breaks down acetylcholine?

Answer 11

acetylcholinesterase

Question 12

How did they reveal nAChR structure?

Answer 12

X-ray and electron microscope analysis

Question 13

What is the mechanism of how nAChR opens?

Answer 13

ACh binds to the two alpha subunits which causes the TM2 segments to rotate allowing ions to pass through the pore.

Question 14

T/F: Nearly all excitatory neurons in the PNS are glutamatergic

Answer 14

False: in the CNS

Question 15

What is glutamate synthesized from?

Answer 15

Glutamine

Question 16

How is newly synthesized glutamate transported into synaptic vesicles?

Answer 16

Vesicular glutamate transporter

Question 17

What happens to excess glutamate?

Answer 17

It is taken up into glial cells, converted into glutamine, and cycled back to the nerve terminal

Question 18

What are the 3 types of ionotropic glutamate receptors?

Answer 18

NMDA, AMPA, and Kainate

Question 19

Which ionotropic glutamate receptor ONLY requires glutamate to open?

Answer 19

AMPA receptors

Question 20

Which ionotropic glutamate receptor requires glutamate AND depolarization to open?

Answer 20

NMDA

Question 21

What are the two main inhibitory neurotransmitters in the CNS?

Answer 21

GABA and glycine

Question 22

What do GABA and glycine do?

Answer 22

They activate chlorine-conducting ionotropic receptors to produce inhibitory postsynaptic potentials (IPSP)

Question 23

Where is GABA is predominant?

Answer 23

cortex and midbrain

Question 24

Where is glycine predominant?

Answer 24

brain stem and spinal cord

Question 25

Where are neuropeptides synthesized?

Answer 25

They are synthesized in cell body and transported to terminal in large dense-core vesicles

Question 26

What do neuropeptides bind?

Answer 26

GPCR