The intra-spine electric force can drive vesicles for fusion: a theoretical model for long-term potentiation

We have estimated the intensity of intra-spine electric fields triggered by stimulation of excitatory spine synapses. We show that this electric force can cause fast electrophoretic movement of negatively charged vesicles which bring new postsynaptic receptors and membrane for insertion during the induction of long-term potentiation (LTP). Due to the direction of an intra-spine electric field, movement of vesicles is electrophoretically directed along the longitudinal spine axis towards the spine head. Thus, the number of fused vesicles may be proportional not only to the increased calcium concentration within the spine head during the induction of LTP but also to the magnitude of electric force which drives vesicles towards the postsynaptic membrane.