A. Dityatev et al., Synaptic strength as a function of post- versus presynaptic expression of the neural cell adhesion molecule NCAM, NEURON, 26(1), 2000, pp. 207-217
To evaluate the contributions of the pre- versus postsynaptic expression of
NCAM in regulation of synaptic efficacy, we cultured dissociated hippocamp
al cells from NCAM-deficient and wild-type mice in homo- and heterogenotypi
c combinations. Double recordings from synaptically coupled neurons maintai
ned in heterogenotypic cocultures showed that synaptic strength of excitato
ry but not inhibitory synapses depended on expression of NCAM post- but not
presynaptically. This correlated with higher levels of potentiation and sy
naptic coverage of NCAM-expressing neurons compared to NCAM-deficient neuro
ns in heterogenotypic cocultures. Synaptic density was the same in homogeno
typic cultures of NCAM-deficient and wild-type neurons as well as in hetero
genotypic cocultures in which glutamate receptors were blocked. These obser
vations indicate that the relative levels of postsynaptic NCAM expression c
ontrol synaptic strength in an activity-dependent manner by regulating the
number of synapses.