Cellular communication 4

Question 1

Ionotropic receptors are

Answer 1

ligand-gated ion channels

Question 2

Most ionotropic receptors cause ________________ events in the postsynaptic target cell

Answer 2

excitatory or inhibitory

Question 3

Ionotropic receptor activation ceases when the

Answer 3

neurotransmitter dissociates from the receptor or when the receptor is desensitized

Question 4

Ligand-gated ion channels are typically named for the

Answer 4

ligand that activates the receptor

Question 5

Metabotropic receptors are

Answer 5

GPCRs

Question 6

GPCR activation ceases when the

Answer 6

neurotransmitter dissociates from the receptor or when the receptor is desensitized

Question 7

Metabotropic receptors participate in _____________ responses compared to ionotropic receptors

Answer 7

slower

Question 8

Examples of metabotropic receptors include

Answer 8

muscarinic AChR, adrenergic receptors, GABAbR, opioid receptors, 5-HT1R

Question 9

Neurotransmitter molecules are packaged into

Answer 9

synaptic vessels

Question 10

There can also be metabotropic receptors on the

Answer 10

presynaptic membrane (autocrine signaling)
typically modulate neurotransmitter release

Question 11

Volatile anesthetics ________________ excitatory transmission and ______________inhibitory neurotransmission

Answer 11

inhibit; enhance

Question 12

Excitatory responses are produced by

Answer 12

a net inward current that usually depolarizes the membrane
ex. Na+ influx, Ca2+ influx, reduced K+ efflux

Question 13

Inhibitory responses occur when an

Answer 13

outward current hyperpolarizes the membrane

Question 14

Examples of inhibitory responses include

Answer 14

increased K+ efflux
Cl- influx
closure of Ca2+ channels

Question 15

Which protein in the docking complex is the calcium sensor?

Answer 15

synaptotagmin

Question 16

Name three signals that open pores in gated ion channels

Answer 16

membrane voltage (electrical)
chemicals (ligands)
pressure (mechanical)

Question 17

Where are nicotinic acetylcholine receptors NOT located?
a. autonomic ganglia
b. neuromuscular junction
c. chromaffin cells in the adrenal medulla
d. sinoatrial node

Answer 17

d. sinoatrial node

Question 18

_____________ is the primary neurotransmitter of peripheral efferent (motor) neural pathways

Answer 18

Acetylcholine (ACh)

Question 19

In the CNS, acetylcholine plays a role in the

Answer 19

modulation of sleep
wakefulness (in the RAS)
learning
memory

Question 20

Acetylcholine synthesis occurs in the

Answer 20

presynaptic nerve terminal

Question 21

Cholinergic receptors can be

Answer 21

ionotropic or metabotropic

Question 22

Nicotinic ACh receptors are _______________ receptors

Answer 22

ionotropic

Question 23

Muscarinic ACh receptors are _______________ receptors

Answer 23

metabotropic

Question 24

ACh acts as a neurotransmitter at:

Answer 24

the neuromuscular junction (NMJ)
autonomic ganglia
terminal synapses of parasympathetic postganglionic fibers
a few sympathetic postganglionic fibers (sweat glands)
non-neuronal cholinergic system

Question 25

The rate-limiting factor of acetylcholine synthesis is the availability of the

Answer 25

substrates
choline
acetyl-CoA

Question 26

______________________- catalyzes the formation of ACh from acetyl-CoA + choline

Answer 26

Choline acetyltransferase (ChAT)

Question 27

______________ hydrolyzes ACh to acetate and choline

Answer 27

Acetylcholinesterase

Question 28

What causes release of ACh into the synaptic cleft?

Answer 28

increased intracellular Ca2+

Question 29

___________- is an antagonist of Ca2+ at the presynaptic terminal

Answer 29

Magnesium
explains why Mag can cause muscle weakness or potentiate neuromuscular blockade

Question 30

Nicotinic ACh receptors are

Answer 30

ionotropic receptors

Question 31

nAChRs are pentameric complexes with two agonist binding cites:

Answer 31

extracellular a/e interface of one alpha subunit
a/o interface of the other alpha subunit

Question 32

___________________________ to the alpha subunits is required to initiate a conformational change that opens the channel in the nAChR.

Answer 32

simultaneous binding of two acetylcholine molecules

Question 33

Nm AChRs are found in

Answer 33

skeletal muscle at the NMJ

Question 34

Nn AChRs are found in

Answer 34

autonomic ganglia
on the chromaffin cells of the adrenal medulla
in the CNS

Question 35

Muscarinic ACh receptors are ______________ receptors

Answer 35

metabotropic

Question 36

Muscarinic AChRs are found in the

Answer 36

CNS
heart
smooth muscle
glands of the GI tract

Question 37

____________ types of mAChR have been identified

Answer 37

five types
M1-M5

Question 38

M1 are found in the

Answer 38

autonomic ganglia
CNS

Question 39

Responses of the M1 receptor are

Answer 39

excitatory
arousal
attention
analgesia

Question 40

The M2 receptor is found in the

Answer 40

heart- nodal tissue & cardiac muscle

Question 41

Responses of the M2 receptor are

Answer 41

decreased chronotropy, decreased inotoropy, decreased dromotropy, hyperpolarization

Question 42

M3 receptors are found in the

Answer 42

smooth muscle
GI

Question 43

Responses of the M3 receptor are

Answer 43

contraction
increased salivary secretions

Question 44

M4 receptors are found in the

Answer 44

CNS

Question 45

Responses of the M4 receptors include

Answer 45

negative feedback to suppress ACh release

Question 46

M5 receptors are found in the

Answer 46

CNS

Question 47

Responses of the M5 receptors include

Answer 47

promotes dopamine release, dilation of cerebral arteries

Question 48

M1, M3 & M5 are coupled to

Answer 48

Gq

Question 49

M2 & M4 are coupled to

Answer 49

Gi