9 - Drug Action on CNS Flashcards
what is the role of choline acetyltransferase (ChAT)?
transfers acetate ions from acetyl-CoA to choline
where is ACh stored?
synaptic vesicles in axonal terminals
where is ACh released?
synaptic cleft on arrival of action potential and influx of Ca2+
where does ACh bind?
muscarinic (M1-5) and nicotinic receptors
what part of ACh is recycled?
choline - from breakdown of ACh
what % of choline formed from ACh breakdown is taken up into presynaptic terminals?
40-50%
how is choline, formed from the breakdown of ACh, taken up into the presynaptic terminal?
by active, high affinity transporters specific to cholinergic cells
the basal forebrain contains two groups of cholinergic neurons - what are they?
- medial septal group
- nucleus basalis group
what neurotransmitter is found at a NMJ?
ACh
what is a NMJ?
a chemical synapse between a motor neurone and skeletal muscle fibre
action of ACh is terminated by what?
AChE
what is myasthenia gravis?
autoimmune condition that affects nerves and muscles causing weakness
what is the pathophysiology of myasthenia gravis?
- immune system produces antibodies that block/damage ACh receptors on muscles
- prevents muscle contracting
- causes weakness
which muscles are most commonly affected in myasthenia gravis?
eye and facial muscles
commonly those that affect swallowing
what medication can be prescribed for mild cases of myasthenia gravis?
pyridostigmine
