Pharmacology Flashcards
What is affinity?
A measure of molecules attraction to a receptor
What is efficacy?
The ability of a molecule to elicit the response at the receptor
What type of receptors are nicotinic ACh receptors?
Ligand gated
What type of receptors are adrenergic receptors?
G protein coupled receptors
How do G protein coupled receptors illicit a response from an effector?
- No signalling, receptor unoccupied, G protein binds GDP
- Agonist activates receptor. G protein couples with receptor. GDP dissociates from alpha subunit, and GTP binds to it. Alpha subunit dissociates from G protein and couples with effector, modifying its activity to turn on the signal
- Alpha subunit hydrolyses GTP to GDP and G protein alpha subunit recombines with beta-gamma subunit, turning off the signal
What type of receptor are insulin receptors?
Kinase associated receptors
How do kinase associated receptors work?
Autophosphorylisation of tyrosine
What type of receptor are steroid receptors?
Nuclear receptors
How do nuclear receptors work?
They diffuse across the cell membrane to the nucleus and bring about changes in transcription bring about their effect
What do depolarisation and repolarisation mean?
Depolarisation - membrane potential becomes more positive
Repolarisation - membrane potential becomes more negative
What are the stages of action potential?
- Resting potential due to sodium outside the cell and negative protein inside the cell
- Ligand such as ACh binds to ligand gated Na channel allowing Na influx and causing depolarisation
- Once threshold is reaches voltage gated Na channels open - further Na influx - AP
- Potassium efflux causes repolarisation
- Voltage goes below resting potential - refractory period where no further AP can occur
Where in CNS do sympathetic and parasympathetic neurones flow from?
Sympathetic - thoracic-lumbar
Parasympathetic - cranio-sacral
What neurotransmitter are the pre and postganglionic neurone s for sympathetic neurones, and which receptors do they act on?
Pre - ACh on nicotinic receptors (ligand gated)
Post - usually noradrenaline on alpha or beta adrenoreceptors (GPRC)
What neurotransmitter are the pre and postganglionic neurone s for PARAsympathetic neurones, and which receptors do they act on?
Pre - ACh on nicotinic receptors (lignand gated)
Post - ACh on muscarinic receptors (GPCR)
Do parasympathetic or sympathetic neurones have a short pre-ganglionic neurone and a long post-ganglionic neurone?
Sympathetic
Parasympathetic have long pre-ganglionic, short post-ganglionic
