L10 - ACh Flashcards
describe synaptic synthesis, storage, release, reuptake, degradation of ACh
what is the common combination of subunits for the nAChR (for ACh) in the CNS
(2x a4) and (3xB2)
(and others)
or
5x a7
what is the common combination of subunits for the nAChR (for ACh) in muscle
2x a1, B1, 1x delta, 1x gamma
how many ACh binding sites are there on the nAChR and where
2
between a and B subunits
what are CNS (ACh) nAChRs permeable to
Na
K
Ca2+
what are muscle (ACh) nAChRs permeable to
mainly just Na and K
what types of a and B subunits of ACh nAChR are found in muscle?
a1
B1
what types of a and B subunit of ACh nAChRs are found in CNS
B2-4
a2-10 (excluding 8)
where is ACh found in the CNS
- cell bodies in caudate nuclei project into thalamus
- nuclei in septum project into cortex annd hippocampus
- cell bodies in magnocellular forbrain project into thalamus, olfactory system and cortex
- interneurones in striatum and retina
describe the differences between a (5x a7) and a (2x a4 + 3x B2) nAChR
(2x a4 + 3x B2) is equally permeable to Na and Ca
(5x a7) is 10 more permeable to Ca
5x a7 has faster desensitisation
it is also less sensitive to ACh (higher EC50)
what are the three important nuclei that are made up of ACh containing neurones
caudate nuclei
septum nuclei
magnocellular forebrain nuclei
ACh (across all types of receptors) can have 3 types of electrical responses, what are they?
- fast depolarisation fast inactivation (nAChRs)
- slow depolarisation slow inactivation (muscarinic via inhiibition of K channels)
- slow hyperpolarisation slow inactivation (muscarinic receptors via inhibition of Ca /Na channels or activation of K channels)
what type of receptors are muscarinic
GPCRs
how many subtypes of muscarinic recpeptor are there and where are they located
what muscarinic recepotrs are found postsynaptically
what G protein are they coupled to
M1, M3, M5
Gq/11