Receptor pharmacology Flashcards
What does Tubocurarine do?
Nicotinic receptor antagonist, competitively preventing ACh from binding, resulting in muscle relaxation
What does Atropine do?
Muscularinic receptor antagonist, competitively preventing ACh from binding
What does Neostigmine do?
AChE inhibitor, resulting in sustained ACh activity
What does Tetrodotoxin do?
Voltage gated sodium channel blocker, inhibiting action potential generation
What does Suxamethonium do?
Nicotinic receptor agonist
How can Suxamethonium be a nicotinic receptor agonist, except be used as a muscle relaxant?
Suxamethonium has a longer duration of effect than ACh and is not broken down by AChE, therefore, preventing muscle cell repolarization
What are the main neurotransmitters and receptors of the sympathetic nervous system?
Adrenaline and NA binding to alpha and beta receptors
What are the pre-ganglionic receptors present in the parasympathetic and sympathetic nervous system?
Nicotinic
What are the post-ganglionic receptors present in the sympathetic nervous system?
Alpha and beta receptors
What does activating alpha-1 receptors do?
- Vasoconstriction of vascular smooth muscle
- Pupil dilation
- Urine retention (sphincter contraction)
- Glycogenolysis
- Inhibit renin release
What does activating alpha-2 receptors do?
- Decrease in intracellular cAMP (inhibits further NA release)
- Decrease insulin secretion
What does activating beta-1 receptors do?
- Increased HR
2. Increase renin (Increased BP)
What does activating beta-2 receptors do?
- Bronchodilation
- Vasodilation
- Decreased gastric motility
- Increased insulin secretion
What receptors does adrenaline show the highest affinity for?
A1, B1, B2 > A2
What receptors does NA show the highest affinity for?
A1 > B1, A2 > B2
Which drugs are selective A1 agonists? antagonist?
Agonist: Phenylephrine
Antagonist: Phentolamine
What are the post-ganglionic receptors present in the parasympathetic nervous system?
Muscularinic
Which catecholamine is most abundant in the blood?
Adrenaline
Briefly outline noradrenaline synthesis
Tyrosine –> L-DOPA –> Dopamine –> Noradrenaline
How does the botulism toxin prevent action potential generation?
Protease which cleaves snare proteins, preventing neurotransmitter vesicle release into the synaptic cleft
Is adrenaline a neurotransmitter?
No, it is a hormone produced by the adrenal medulla
What are the six steps of signal transduction?
- Recognition
- Transduction
- Transmission
- Modulation of an effector
- Response Termination
