Flashcards in Receptors I Deck (51)
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1
What drug type creates a response in the cell
agonist
2
What is occupation of a drug-receptor governed by?
Affinity
3
What is activation of a drug-receptor governed by?
efficacy
4
What part of a drug receptor reaction is reversible
occupation forming a complex
5
What is the ratio of reversibility of a drug receptor reaction governed by?
affinity of the drug
6
Describe the reversibility of drugs with high affinities
slow reversibility
7
Describe occupancy
proportion of receptors occupied will vary with the drug concentration
8
What does occupancy vary between
0 and 1
9
How much drug is present at 0 occupancy
none
10
How can we measure occupancy
by measuring response
11
Describe the relationship between occupancy and response
high occupancy means there is a large response
12
Can you measure antagonists activity using occupancy
NO
13
Examples of ligands
neurotransmitters, hormones, growth factors, cytokines, drugs, toxins
14
Examples of protein targets
receptors, ion channels, enzymes, transporters
15
Describe a ligand binding practical
tissue prep with radio-ligand, incubation, filtration, rinse, count, data analysis
16
True or False - most ligands bind non-specifically to tissue, filter paper, glass
TRUE
17
How can non-specific ligand binding be reduced
reduced by anti-absorbants
18
What are some examples of anti-absorbants
albumin, collagen, o-catechol
19
What is the function of rinsing in a ligand binding practical
remove unbound radioligand from incubation medium
20
What is a key measurement in receptor ligand assays
specific and non specific binding
21
What are the disadvantages of using a radio ligand
degradation
22
How can you prevent degradation of radio ligands
free radical scavenger, store at low temp, avoid light, incorporation of antioxidant
23
What are radio ligands labelled with
radio active labels
24
Name two radio labels
tritum, iodine
25
What are the disadvantages of tritum
specialised labs required, expensive
26
What are the advantages of tritum as a label
high specific activities, good stability, long half life
27
What are the advantages of iodine as a label
easy and cheap, if aromatic hydroxyl group can be incorporated at high specific activities
28
What are the disadvantages of iodine
more readily degraded, short half life, activity of ligand can be reduced
29
What tissue would you select for your ligand binding practical
tissue that contains the receptors of interest
30
