L126- Ion channel and role in hypertension 1 Flashcards Preview

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Flashcards in L126- Ion channel and role in hypertension 1 Deck (30)
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1
Q

give an example of a monovalent cation?

A

Na+ and K+

2
Q

give an example of divalent cations?

A

Ca2+ and Mg2+

3
Q

name 3 types of passive transport?

A
  • simple diffusion
  • channel mediated
  • transporter mediated
4
Q

name a type of active transport?

A

active transport using carrier proteins

5
Q

what is a ionotropic receptor?

A

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

6
Q

what are the 4 types of ion channels?

A
  • voltage gated
  • ligand-gated extracellular
  • ligand gated intercellular
  • mechanically gated
7
Q

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

A

5 or 4 or 3

pentameric, tetrameric, trimeric

8
Q

there is a low concentration of what outside the cell?

A

K+

9
Q

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

A

a chemical

10
Q

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

A
  • there are around 20 transmembrane domains (variable)
  • loops link the Transmembrane domains together.
  • N and C termi
11
Q

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

A
  • cys-loop family of ion channels

- other ligand-gated ion channels

12
Q

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

A
  • Nicotinic acetylcholine receptor
  • GABAA receptor
  • 5-HT3 receptor
13
Q

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

A
  • Glutamate receptors

* P2X receptors

14
Q

what are some facts about voltage-gated ion channels?

A
  • 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.
15
Q

how do voltage-gated ion channels open?

A

• Voltage-gated ion channels have several transmembrane domains

16
Q

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

A

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

17
Q

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

A

Kv channels and inward rectifying K+ channels

18
Q

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

A

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

19
Q

what does a S4 domain do?

A

senses change in them membrane potential

20
Q

what is a tetramer?

A

when alpha subunits come together.

21
Q

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

A

• α1 subunit is the channel pore

22
Q

what are the auxiliary subunits?

A

βsubunit, γ subunit and an α2-δsubunit

23
Q

what are the different types of CaV channels?

A
  • L-type (CaV1)
  • P/Q-type (CaV2.2)
  • N-type (CaV2.1)
  • R-type (CaV2.3)
  • T-type (CaV3)
24
Q

what genes do L-TYPE have?

A

4 genes encoding different α1 subunits

25
Q

what is Ca2+ important for?

A

cardiac muscle and smooth muscle contraction

26
Q

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

A

in the heart and vascular smooth muscle

27
Q

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

A

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

28
Q

what are some types of Cav channel?

A
  • Phenylalkylamines–verapamil preferential for heart

* Dihydropyridines–nifedipine preferential for hypertension • Benzothiazepines-diltiazem

29
Q

what occurs during inactivation state?

A

Drugs interfere with voltage-dependent cycling between resting – open

30
Q

where do drugs bind?

A

Drugs bind to separate sites that are allosterically linked