Article

Microtubules to form memory.

Department of Neurosurgery, Fujita Health University, Toyoake, Aichi, Japan.
Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia 01/2008; 113(4):227-35.
Source: PubMed

ABSTRACT Microtunbule-depolymerizing agents cause amnesia. Some signal translocations to the stimulated postsynaptic membrane are essential for inducing LTP in CA1 neurons like AMPA receptors, CaMKII and mRNA. On the other hand, LTP requires protein synthesis and gene expression. This indicates that signals generated at the synapse might be transmitted to the nucleus. Recently, we have reported that LTP-producing stimulation makes new microtubule track between cell body and the stimulated postsynaptic membrane in CA1 neurons. This newly produced microtubule track only to the stimulated postsynaptic membrane might be the route of these bi-directional transportation of signals during LTP formation. This lead us the hypothesis of the "endless memory amplifying circuit" that means gene expression-promoting molecules are translocated from postsynaptic membrane to the cell body and enter into nucleus and activate transcription factors, and gene products, which will probably promote plasticity, may be re-translocated only to the stimulated postsynaptic membrane along microtubules.

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    • "The newly produced microtubules are localized only to the stimulated postsynaptic spine and that might be the route of the bidirectional dendritic transportation of signals during LTP formation. This led us to hypothesize the " endless memory amplifying circuit " (Figure 3), proposing that retrograde gene expression-promoting molecules, such as CaMKIV, are translocated from postsynaptic membrane to the cell body, enter into the nucleus, and activate transcription factors; anterograde gene products such as AMPA receptors [39] and CaMKII may be retranslocated only to the stimulated postsynaptic membrane along microtubules, as we have proposed previously [40] "
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