L126- Ion channel and role in hypertension 1

Question 1

give an example of a monovalent cation?

Answer 1

Na+ and K+

Question 2

give an example of divalent cations?

Answer 2

Ca2+ and Mg2+

Question 3

name 3 types of passive transport?

Answer 3

• simple diffusion
• channel mediated
• transporter mediated

Question 4

name a type of active transport?

Answer 4

active transport using carrier proteins

Question 5

what is a ionotropic receptor?

Answer 5

membrane-bound receptor proteins that respond to ligand binding by opening an ion channel and allowing ions to flow into the cell

Question 6

what are the 4 types of ion channels?

Answer 6

• voltage gated
• ligand-gated extracellular
• ligand gated intercellular
• mechanically gated

Question 7

how many sub-units are there in Ligand-gated ion channel structure?

Answer 7

5 or 4 or 3

pentameric, tetrameric, trimeric

Question 8

there is a low concentration of what outside the cell?

Answer 8

K+

Question 9

what is the ligand for Ligand-gated ion channel structure?

Answer 9

a chemical

Question 10

explain a subunit of a Ligand-gated ion channel structure?

Answer 10

• there are around 20 transmembrane domains (variable)
• loops link the Transmembrane domains together.
• N and C termi

Question 11

what are the two types of ligand-gated ion channel families?

Answer 11

• cys-loop family of ion channels

- other ligand-gated ion channels

Question 12

what are the examples of cys-loop family ion channels?

Answer 12

• Nicotinic acetylcholine receptor
• GABAA receptor
• 5-HT3 receptor

Question 13

what are the examples of other ligand-gated ion channels?

Answer 13

• Glutamate receptors

* P2X receptors

Question 14

what are some facts about voltage-gated ion channels?

Answer 14

• Transmembrane potential l exists across plasma membrane
• Inside of cell is negative with respect to the outside
• Voltage-gated ion channels have several transmembrane domains.

Question 15

how do voltage-gated ion channels open?

Answer 15

• Voltage-gated ion channels have several transmembrane domains

Question 16

what is the inactivation stage in voltage-gated Na+ channels?

Answer 16

it is the phase after the gate is closed it becomes inactive. when the membrane is still depolarised.

Question 17

what are the two main families of voltage-gated K+ channels?

Answer 17

Kv channels and inward rectifying K+ channels

Question 18

whats the difference between Kv and inward rectifier K+ channels?

Answer 18

Kv have 6 transmembrane domains and inward rectifier K+ have 2 transmembrane domains

Question 19

what does a S4 domain do?

Answer 19

senses change in them membrane potential

Question 20

what is a tetramer?

Answer 20

when alpha subunits come together.

Question 21

where is the pore in a voltage-gated Ca2+ channel?

Answer 21

• α1 subunit is the channel pore

Question 22

what are the auxiliary subunits?

Answer 22

βsubunit, γ subunit and an α2-δsubunit

Question 23

what are the different types of CaV channels?

Answer 23

• L-type (CaV1)
• P/Q-type (CaV2.2)
• N-type (CaV2.1)
• R-type (CaV2.3)
• T-type (CaV3)

Question 24

what genes do L-TYPE have?

Answer 24

4 genes encoding different α1 subunits

Question 25

what is Ca2+ important for?

Answer 25

cardiac muscle and smooth muscle contraction

Question 26

where are L-type Ca2+ channels (CaV1.2 and CaV1.3) found?

Answer 26

in the heart and vascular smooth muscle

Question 27

what drugs can be used to control heart rate and vascular tone?

Answer 27

calcium channel blockers (antagonists) as L-type Ca2+ channel are found in the heart

Question 28

what are some types of Cav channel?

Answer 28

• Phenylalkylamines–verapamil preferential for heart

* Dihydropyridines–nifedipine preferential for hypertension • Benzothiazepines-diltiazem

Question 29

what occurs during inactivation state?

Answer 29

Drugs interfere with voltage-dependent cycling between resting – open

Question 30

where do drugs bind?

Answer 30

Drugs bind to separate sites that are allosterically linked