give an example of a monovalent cation?
Na+ and K+
give an example of divalent cations?
Ca2+ and Mg2+
name 3 types of passive transport?
- simple diffusion
- channel mediated
- transporter mediated
name a type of active transport?
active transport using carrier proteins
what is a ionotropic receptor?
membrane-bound receptor proteins that respond to ligand binding by opening an ion channel and allowing ions to flow into the cell
what are the 4 types of ion channels?
- voltage gated
- ligand-gated extracellular
- ligand gated intercellular
- mechanically gated
how many sub-units are there in Ligand-gated ion channel structure?
5 or 4 or 3
pentameric, tetrameric, trimeric
there is a low concentration of what outside the cell?
K+
what is the ligand for Ligand-gated ion channel structure?
a chemical
explain a subunit of a Ligand-gated ion channel structure?
- there are around 20 transmembrane domains (variable)
- loops link the Transmembrane domains together.
- N and C termi
what are the two types of ligand-gated ion channel families?
- cys-loop family of ion channels
- other ligand-gated ion channels
what are the examples of cys-loop family ion channels?
- Nicotinic acetylcholine receptor
- GABAA receptor
- 5-HT3 receptor
what are the examples of other ligand-gated ion channels?
- Glutamate receptors
* P2X receptors
what are some facts about voltage-gated ion channels?
- 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.
how do voltage-gated ion channels open?
• Voltage-gated ion channels have several transmembrane domains
what is the inactivation stage in voltage-gated Na+ channels?
it is the phase after the gate is closed it becomes inactive. when the membrane is still depolarised.
what are the two main families of voltage-gated K+ channels?
Kv channels and inward rectifying K+ channels
whats the difference between Kv and inward rectifier K+ channels?
Kv have 6 transmembrane domains and inward rectifier K+ have 2 transmembrane domains
what does a S4 domain do?
senses change in them membrane potential
what is a tetramer?
when alpha subunits come together.
where is the pore in a voltage-gated Ca2+ channel?
• α1 subunit is the channel pore
what are the auxiliary subunits?
βsubunit, γ subunit and an α2-δsubunit
what are the different types of CaV channels?
- L-type (CaV1)
- P/Q-type (CaV2.2)
- N-type (CaV2.1)
- R-type (CaV2.3)
- T-type (CaV3)
what genes do L-TYPE have?
4 genes encoding different α1 subunits
what is Ca2+ important for?
cardiac muscle and smooth muscle contraction
where are L-type Ca2+ channels (CaV1.2 and CaV1.3) found?
in the heart and vascular smooth muscle
what drugs can be used to control heart rate and vascular tone?
calcium channel blockers (antagonists) as L-type Ca2+ channel are found in the heart
what are some types of Cav channel?
- Phenylalkylamines–verapamil preferential for heart
* Dihydropyridines–nifedipine preferential for hypertension • Benzothiazepines-diltiazem
what occurs during inactivation state?
Drugs interfere with voltage-dependent cycling between resting – open
where do drugs bind?
Drugs bind to separate sites that are allosterically linked