Acetylcholine

Question 1

Density of ACh receptors in NMJ

Answer 1

10,000 per square micrometer

Question 2

About how many ACh molecules in a synaptic vesicle?

Answer 2

7000

Question 3

Single channel conductance of ACh channel when open?

Answer 3

30 pS

Question 4

Two things which limit time course of current at NMJ

Answer 4

1. intrinsic property of nACh receptors

2. AChE, rather than reuptake, clears ACh

Question 5

EPP at NMJ lasts about

Answer 5

10-15ms

Question 6

How do organophosphates cause paralysis?

Answer 6

Inhibit AChE
Causes ACh to accumulate in synapse
Cell is depolarized and thus refractory to subsequent ACh release

Question 7

Graph of NMJ current with organophosphate and w/o

Answer 7

…

Question 8

Examples of organoposphate

Answer 8

serine

prostigmine

Question 9

IV graph of nACh receptor

Answer 9

…

Question 10

Reverse potential of nACh receptor

Answer 10

0

Question 11

nACh receptors conduct which ion?

Answer 11

Non-selective cation channel

Question 12

nACh receptors have how many subunits?

Answer 12

5

Question 13

Ligand binds nACh receptors at:

Answer 13

both alpha subunits

Question 14

Each subunit of the nACh receptor includes:

Answer 14

4 TM domains and a large extracellular domain

Question 15

Compare width of nACh recptot pore to voltage-gated channels

Answer 15

Large (non-selective)

Question 16

Blocks nACh receptors

Answer 16

Curare

Competitively

Question 17

In a muscarinic ACh receptor, ACh binds

Answer 17

A single site

Question 18

When ACh binds muscarinic ACh receptor,

Answer 18

Conformational change is induced, activating G protein
This opens GIRK channel
Potassium leaves
Hyperpolarization (slows heart rate)

Question 19

Muscarinic ACh receptor has _ TMD

Answer 19

7

Question 20

8ms

Answer 20

Fastest slow synaptic transmission

Question 21

10-100ms

Answer 21

General time range for slow synaptic transmission