Autonomic and NMJ Pharmacology Flashcards
How many types of cholinergic receptors exist?
2, ionotropic (ion channel nicotinic receptor) and metabotropic (g-protein)
How many types of adrenergic receptors exist?
1, metabotropic
What is the function of presynaptic autoreceptors?
Bind to transmitter,
inhibits voltage gated Calcium channels
reduces further transmitter release
Where is the neurotransmitter usually metabolised?
Within the cell
What are the two components of the NMJ?
Efferent motor neurones and the skeletal muscle
Give examples of how you could stop the NMJ synapses working well?
Stop acetylcholine being packaged into vesicles
Stop vesicle release by blocking calcium channels
Stop vesicle release by preventing vesicle fusion
Blocking post synaptic nicotinic receptors
Use an agonist to keep these receptors open, causes brief muscle twitching and then paralysis as voltage gated channels stay in their refractory state
How can you make the NMJ synapses work better?
Prolong action potential, by letting in more calcium ions and releasing more acetylcholine
Stop the breakdown of acetylcholine by blocking the enzyme acetylcholinesterase
What can depolarizing and non-depolarizing blockers be used for paralysis?
Surgical procedures, controlling spasms in tetanus
What can anticholinesterases be used for?
Treating myasthenic conditions
Reversing action of non-depolarizing blockers
Stops the breakdown of Ach by blocking the acetylcholinesterase so it hangs around in the synaptic cleft for longer.
How can you stop transmission in the ANS at the ganglion?
Inhibit ACH, Ca2+
Why can you activate nicotinic receptors at the ganglion using Nicotine but not at the NMJ?
Nicotine is more potent at the ganglion
Why are there no clinical applications of ganglionic transmission modulation?
Drugs modulate parasympathetic and parasympathetic ganglionic transmission and probably NMJ transmission too, producing complex actions with many side-effects
What can parasympathetic postganglionic transmission be affected by
Muscarinic receptor agonists
Muscarinic receptor antagonists
What is gluacoma characterised by?
High intraoccular pressure
Where does aqeous humour normally drain?
Through the trabecular network into the canal of schlemm
