Postsynaptic Receptors

Question 1

CONVERSION  of a message from one form (neurotransmitters)
into another (increased membrane conductance. Is know as what?

Answer 1

Transduction

Question 2

The transduction mechanism is described as direct-gating

(or ligand-gating). This is used by which type of receptors?

Answer 2

Ionotropic

Question 3

The transduction mechanism is described as indirectgating. This is used by which type of receptors?

Answer 3

Metabotropic-type receptors

Question 4

Ionotropic-type receptors uses ___ gating that neurotransmitter binding to the receptor
causes a CONFORMATIONAL CHANGE in the ion channel complex
to open the gate and provide conductance across the
membrane for a selected ion, or ions.

Answer 4

Direct

Question 5

The neuromuscular ACh receptor is classified as _____.

Answer 5

Nicotinic cholinergic

Question 6

two molecules of ACh must bind
to the two ___subunits to activate
the receptor

Answer 6

Alpha

Question 7

The selectivity filter of ___ is cation selective,

providing conductance for both Na+ and K+

Answer 7

Neuromuscular junction

Question 8

INDIRECT GATING is used by what type of ___ receptors?

Answer 8

Metabotropic-type

Question 9

Is there an measurable delay in metabotropic receptors compared to ionotropic receptors?

Answer 9

YES.

Question 10

With ___ receptors, the extracellular signal (neurotransmitter)
must be brought into the cell (“internalized”) to effect the functional
response

Answer 10

Metabotropic

Question 11

What is the first messenger that takes extracellular message into the cell?

Answer 11

Neurotransmitter

Question 12

1. ___ (→ “first messenger”) binds to
   the receptor
2. the ligand-activated receptor complex activates a
   G-protein (_____)
3. the activated G-protein translocates along the
   membrane to activate a _____.
4. the activated primary effector generates an
   intracellular _____.
5. the second messenger activates a _____.

Answer 12

1. neurotransmitter
2. transducer
3. primary effector
4. second messenger
5. secondary
   effector

Question 13

Is second intracellular?

Answer 13

Yes.

Question 14

What is the function of the second messenger?

Answer 14

Process the message (internalizing) brought into intracellular side from extracellular side.

Question 15

What enzyme serves as the primary effector?

Answer 15

Adenylyl cyclase

Question 16

What will activate adenylyl cyclase?

Answer 16

G-protein

Question 17

When G- protein is in an inactive state, adenylyl cyclase is___.

Answer 17

INACTIVE (G-protein will not activate adenylyl cyclase)

Question 18

The signaling cascade starts with ___ binding to its
receptor, which activates the ___, leading to activation of the
___ and generation of the second messenger.

Answer 18

1. neurotransmitter
2. G-protein
3. primary effector

Question 19

The ligand-receptor complex
continues to reactivate inactive Gproteins until the neurotransmitter
_____ from the receptor

Answer 19

detaches

Question 20

To cause the gate on an ion channel to open, there must be an
intracellular signal … this is provided by ___ of the
channel.

Answer 20

phosphorylation

Question 21

Attaching an inorganic phosphate (Pi
) to an internal segment of the
membrane-spanning channel. This is known as?

Answer 21

Phosphorylation

Question 22

When a channel is DE-phosphorylated, what happens?

Answer 22

Channel will close

Question 23

When a channel is phosphorylated, what happens?

Answer 23

Channel will open

Question 24

What is the second messenger known as?

Answer 24

cAMP

Question 25

The intracellular target for cAMP (the | second messenger) is cAMP-dependent kinase which is known as_____.

Answer 25

protein kinase A, or PKA

Question 26

phosphodiesterases ___ cAMP.

Answer 26

inactivate

Question 27

protein phosphatases remove | _____from proteins.

Answer 27

phosphate groups

Question 28

cAMP is activated by___.

Answer 28

Activated adenylyl cyclase.

Question 29

Adenylyl cyclase is activated by___.

Answer 29

G- protein

Question 30

G-protein is activated by___.

Answer 30

Neurotransmitter, stimulating postsynaptic receptor

Question 31

When neurotransmitter detaches from postsynaptic receptors we want the ion channels to ___.

Answer 31

Close: signaling communication is over.

Question 32

Why do we want to remove neurotransmitter from postsynaptic receptor after message is conveyed?

Answer 32

So it won't keep repeating the same message over and over again.

Question 33

Ionic channel wont close unless _____.

Answer 33

Dephosphorylated via protein phosphatases

Question 34

Another G-protein coupled signaling mechanism that is | commonly employed in neurons is the _____.

Answer 34

Phosphoinositol system

Question 35

phospholipase Cβ (PLC) is the primary | effector activated by the_____.

Answer 35

G-protein | subunit Gq

Question 36

``` Both IP3 (inositol trisphosphate) and DAG (diacylglycerol) are generated as _____through cleavage of phosphatidylinositol bisphosphate (PIP2) by phospholipase C ```

Answer 36

Second messengers

Question 37

DAG (diacylglycerol) will bind with the _____ of protein kinase C

Answer 37

Regulatory subunit

Question 38

IP3 signals via a receptor along the _____ for that organelle to release Ca++ into the cytosol

Answer 38

Endoplasmic reticulum

Question 39

Secondary Effectors: | Protein kinase C is activated by ___.

Answer 39

DAG

Question 40

Ca++/calmodulin dependent protein kinase is | activated when Ca++ binds to ___

Answer 40

Calmodulin

Question 41

The effectiveness of signaling through the calcium-calmodulin pathway is based upon an acute increase in the ______.

Answer 41

Cytosolic Ca++ concentration

Question 42

The mechanism for indirect activation of a K+ channel via a _____receptor.

Answer 42

Muscarinc | acetylcholine

Question 43

Nicotinic cholinergic | receptors are ___ gated

Answer 43

Directly

Question 44

What is the first messenger, receptor, and second messenger(s) in the cAMP system?

Answer 44

Norepinephrine; Beta-adrenergic receptor; cAMP

Question 45

What is the first messenger, receptor, and second messenger(s) in the Phosphoinositol system?

Answer 45

ACh; Type 1 Muscarinic ACh receptor; IP3 and DAG

Question 46

What is the first messenger, receptor, and second messenger(s) in the Direct G protein-gating system?

Answer 46

ACh; Type 2 Muscarinic ACh receptor; G protein-gated K+ channel

Question 47

In general, G-proteins function as a molecular _____ operated through binding and then release of neurotransmitter from its postsynaptic receptor.

Answer 47

on – off switch

Question 48

α-GDP is active/inactive?

Answer 48

Inactive

Question 49

α-GTP is active/inactive?

Answer 49

Active

Question 50

_____ receptors: ion channels DO NOT respond immediately to neurotransmitter binding and releasing from the receptor.

Answer 50

Metabotropic

Question 51

_____ receptors: ion channels RESPOND immediately to neurotransmitter binding and releasing from the receptor.

Answer 51

Ionotropic

Question 52

The state of ___ to determine whether the channel is open or closed.

Answer 52

Phosphorylation

Question 53

Protein kinase A and phosphoprotein phosphatase-1 are _____ signals that are regulated by _____ signaling via membrane receptors.

Answer 53

Intracellular; external signaling

Question 54

The “strength” of phosphorylation in response to cAMP is: _____ when PP-1 is inhibited.

Answer 54

Enhanced

Question 55

The “strength” of phosphorylation in response to cAMP is: _____ (lessened) when PP-1 is active.

Answer 55

Diminished

Question 56

PP-1 (phosphatase-1 ) is regulated via another intracellular signaling molecule, _____.

Answer 56

Inhibitor-1

Question 57

``` _____ modulates (lessens) channel phosphorylation in response to cAMP by causing the DISINHIBITION of PP-1 ```

Answer 57

calcineurin

Question 58

Calcineurin is activated by?

Answer 58

Calcium