Drugs and receptors Flashcards
what is a receptor
part of a cell that interacts with a specific ligand and initiates a change of biochemical events leading to ligand observable effects
what classes of chemicals can receptors communicate with
Neurotransmitters
Autacoids
Hormones
What type of receptors are there
Ligand gated ion channels
G protein-coupled receptors
Kinase linked receptors
Cytosolic/nuclear receptors
What are G protein-coupled receptor? (GPCR)
Family of proteins involved in transmitting signals from GPCR’s
what binds to and hydrolised GTP and GDP (guanine triphosphate + Guanine diphosphate
G proteins (gioamome. nucleotide-binding-proteins)
what is a kinase
Enzymes that catalyse the transfer of phosphate groups
What is a nuclear receptor and how do they worl
Steroid hormone receptors
Worryk by modifying gene transcription
has zinc fingers that bind to DNA
what type of cancer is tamoxifen used
Estrogen receptor+ cancers
give an example where an inbalance in chemicals can lead to a pathology
Allergy –> inc histamine
Parkinsons –> reduced histamine
Give and example where an imbalance in receptor can lead to a pathology
Myasthenia gravis – loss of ACh receptors
Mastocytosis –> increased c-kit receptor
What is an agonist
a compound that binds to a receptor and activated it
what is an antagonist
- A compound that reduces the effect of an agonist
- Affinity but not efficacy
give the equation for intrinsic activity
intrinsic activity = Emax of partial agonist / Emax of full agonist
What does intrinsic activity mean
the ability of a drug-receptor complex to produce a maximum function response
what is selective agonism
potency of a range of agonists
What is selective antagonism
competitive antagonists
is nicotine nad agonist or antagonist
agonist
What are all the histamine receptors characterized as
H1 = allergy
H2 - Gastric acid secretion
H3 = Monstly CNS disorders (narcolepsy, ADHD, alzheimers)
H4 = immine system and inflammatory conditions (asthma, arthritis)
wgat is effacacy
Described how well a ligand activates the receptor
T/F agonists have no affinity but have effacacy
F
Agonists Have affinity and efficacy
T/F antagonists have affinity but no efficacy
T
what is an irreversible antagonist
irreversibly dound to a receptor
Define inverse agonism
drug that binds to the same receptor as an agonist but induces a pharmacological response opposite to that of an agonist
Describe tolerance
-Reduction in agonist effect over time
-continuously, repeatedly, high cons
Descripe desensitization
Uncouples, internalized, degraded
what are the passive ion transporters
Symporters and channels
What are the active ion treansporter
ATP-ases
Competitive agonists are
a) Surmountable and irreversible
b)surmountable and reversible
c)insurmountable and irreversible
d)insurmountable and reversible
b
Non competetive agonists are
a) Surmountable and irreversible
b)surmountable and reversible
c)insurmountable and irreversible
d)insurmountable and reversible
C
what is the difference between a Full, partial and Inverse AGONIST
Full agonist: high efficacy, produces** full respons**e while occupying a relatively low amount of receptors. **Affinity but efficacy
**
-Partial agonist: lower efficacy than a full agonist. It produces sub-maximal activation even when occupying the total receptor population; therefore cannot produce the maximal response, irrespective of the concentration applied. Won’t reach eMax
-Inverse agonist: effect opposite to that of an agonist, yet **binds to the same receptor binding site as an agonist **
