L14 GOK Flashcards
Wnt3a involved in D-V of what ?
retina ganglion cells
motor unit is ?
consists of 1 motor neuron and all the muscle fibres it innervates
each motor has one of 3 types of muscle fibre name muscle fibre types ?
fast twitch , slow twitch , intermediate
NT @ NMJ ?
ACH
nitotinic receptors at postsynapse
what fills synaptic cleft ?
synaptic basal lamina
where are the ACHR located ?
post junctional folds - crest
trough contains NA+ channels
active zone ?
where NT accumulate in vesicles (presynapse)
where do the signals for pre/postsynaptic differentiation localise?
synaptic basal lamina
whats basal lamina?
strong , fibrous permeable matrix for cell attachment
prepatterning ?
clustering of ACHR before axon arrival
once nerve arrives what happens to clusters ?
large clusters form whereaxon innervates while you get disappearance of primitive clusters in non synaptic areas
whats agrin ?
a signal for post-synaptic differentiation secreted by axon
what does agrin do ?
agrin KO ?
causes ACHR clustering
abnormal synapses
choline actyltransferase CHAT KO = ?
synapse formation (LESS ach)
what affect does ACH have on synaptic differentiation
destabilises synapse with no agrin
DKO of agrin and CHAT
synapse formation
initially in agrin KO synapses still form but then theres loss of synapse as time goes on what does this tell us ?
other signals involved in synapse formation eg wnt
agrin required for synapse maintenance
what happens when ACH agonist is added to culture with ACHR clustering ?
the clusters disperse
MUSK is ?
KO ?
muscle specific kinase - receptor tyrosine kinase
component of agrin receptor complex
ko - abnormal synapse NMJ - lack clustering
LRP4 ?
a member of the low density
lipoprotein receptor family.
Essential for synapse formation
lrp4 -/- mice identical MuSK -/- mice
agrin binds LRP4 what happens ?
MUSK phosphorylated
Rapsyn can bind what ?
ACHR and MUSK (p)
pulls ACHR into synapse
