1 - Drug interactions with receptors and ion channels Flashcards
Benzilylcholine mustard
Irreversibly alkylates muscarinic receptor
Cholera toxin
ADP ribosylation of a(s)
Inhibits GTPase activity
Sustained activation of adenylyl cyclase
Pertussis toxin
ADP ribosylation of a(i)
Prevents activation of Gi in response to receptor stimulation
AIF4-
Mimics gamma-phosphate of GTP
Causes persistent activation of G proteins
Lithium
Uncompetitively inhibits phosphatases converting IP1 to inositol
Blocks inositol recycling
Tyrphostins
Inhibitors of tyrosine kinase
Prednisolone
Agonist for glucocorticoid receptors
Mifepristone
Antagonist for glucocorticoid receptors
Fludrocortisone
Agonist for mineralocorticoid receptors
Spironolactone
Antagonist for mineralocorticoid receptors
Ethinylestradiol
Agonist for estrogen receptor
Tamoxifen
Antagonist for estrogen reveptor
Norethisterone
Agonist for progestagen receptor
Danazol
Antagonist for progestagen receptor
Lidocaine
- 2 main uses
- what fibres does it affect?
- what does it bind to?
- acid or base?
- how does it act in different pHs?
-Local anaesthetic
Antidysrhythmic agent
-Affects c and Adelta fibres
-Binds preferentially to and stabilises inactivated state (Na channels)
-Weak base
-High ph-greater inhibition, lower potency
Procaine
- main uses
- what fibres does it affect?
- what does it bind to?
-Local anaesthetic
Antidysrhythmic agent
-Affects c and Adelta fibres
-Binds preferentially to and stabilises inactivated state (Na channels)
QX314
Quaternary local anaesthetic
Ineffective outside axon
Potent LA when perfused inside
Benzocaine
Local anaesthetic
Uncharged
Extent of block is independent of pH
Faster block - hydrophobic pathway within membrane for uncharged LAs
Quinidine
Local anaesthetic
Slow in slow out
Use dependence at low rates of stimulation
Tetrodotoxin
TTX
Guanidinium groups
Block Na channels from outside
Do not show use dependence
Bay K 8644
Dihydropyridine (DHP)
Calcium agonist
Lipid soluble
Nifedipine
Dihydropyridine (DHP)
Lipid soluble
Calcium antagonist
Verapamil
Ca channel blocker Bind to site away from DHP binding site Site interact, so reduces DHP binding Use dependence Prolonged block Preferentially cardiac muscle Antidysrhythmics
Diltiazem
Ca channel blocker Bind to site away from DHP binding site Site interact, so enhances DHP binding Use dependence Prolonged block Preferentially cardiac muscle Antidysrhythmics
Diazoxide
K channel opener
Hyper polarise cell membrane
Relax smooth muscle
Minoxidil
K channel opener
Hyper polarise cell membrane
Relax smooth muscle
Nicorandil
K channel opener
Hyper polarise cell membrane
Relax smooth muscle
Tolbutamide
How does it work?
Close Katp acting on sulphonylurea receptor Depolarise pancreatic B cell memb Fires VGCa channel Ca influx Insulin release
Glibenclamide
How does it work?
Close Katp acting on sulphonylurea receptor Depolarise pancreatic B cell memb Fires VGCa channel Ca influx Insulin release
Muscarine
Agonist for muscarinic receptor on smooth muscle
Nicotine
Agonist for nicotinic receptor on skeletal muscle
Atropine
Antagonist for muscarinic receptor on smooth muscle
D-tubocurarine
Antagonist for nicotinic receptors on skeletal muscle
Acetyl-B-methylcholine
Cholinergic agonist
Inactive isomer has no affinity
Isoprenaline
B-adrenoreceptor agonist
Inactive isomer has affinity
Adenosine
?
a bungarotoxin
?
Lidocaine
- how does it cross the membrane and block the channel?
- dependence?
- what in what out?
-Cross membrane in uncharged form Blocks channel best in charged form -Use dependence at high rates of stimulation Voltage dependence -Fast in fast out
Procaine
- acid or base?
- how does it act in different pHs?
- how does it cross the membrane and block the receptor?
-Weak base
-High ph-greater inhibition, lower potency
-Cross membrane in uncharged form
Blocks channel best in charges form
Tolbutamide
What is it and what does it do/treat?
Orally acting hypoglycaemic agent
Treat type 2 diabetes
Sulphonylurea
Glibenclamide
What is it, what does it do/treat?
Orally acting hypoglycaemic agent
Treat type 2 diabetes
Sulphonylurea