L2 - Receptors - Receptors and drug action Flashcards
How do most drugs exert their effects?
by interefering with a receptor
What drug acts at the mu-opiod receptor to stop the action of opiods?
Naloxone
Ligand gated ion channels…
- Known as ionotropic receptors.
- 4 or 5 transmambrane domains.
- Fastest acting receptor.
- Faces outwards on the membrane.
- eg. nAchR, GABAa
G-Protein coupled receptors…
Known as metabtropic receptors.
7 transmembrane domains.
Can face outwards or inwards (embedded) on the membrane.
Kinase Linked receptors…
1 transmembrane domain.
Faces outwards on the membrane.
What is a kinase?
any molecule that works to add phosphate to another molecule.
Nuclear Receptors…
Found inside the cells or in the nucleus.
No transmembrane domains so are not anchored to the membrane.
What is a common feature in all receptors?
A DNA binding domain to regulate transcription of genes in cells.
What is located in the centre of a ligand gated ion channel to regulate the flow of ions?
An aqueous pore
What proteins are under the cys-loop type (pentameric) of ligand gated ion channels?
Nicotinic acetylcholine receptors (nACHRs)
GABA receptors
Seotonin receptors (5HT)
What proteins are under the ionotropic glutamate type (tetrameric) of ligand gated ion channels?
NMDA
What proteins are under the calcium release type (pentameric) of ligand gated ion channels
IP3R
Ryanodine receptors (RyR)
Outline the canonical signalling by GPCRS (G-protein coupled receptors)
1 - an agonist binds to the receptor
2 - The GDP bound to the alpha subunit converts to GTP
3 - This causes the beta-gamma subunit to dissociate from the alpha subunit.
4 - Separately the GTP bound alpha subunit and the beta-gamma subunit may interact with downstram effector proteins, this brings about the change.
