NMDA receptor triggered molecular cascade underlies compression-induced rapid dendritic spine plasticity in cortical neurons.

NMDA receptor triggered molecular cascade underlies compression-induced rapid dendritic spine plasticity in cortical neurons. Exp Neurol. 2015 Feb 20; Authors: Chen LJ, Wang YJ, Chen JR, Tseng GF Abstract Compression causes the reduction of dendritic spines of underlying adult cortical pyramidal neurons but the mechanisms remain at large. Using a rat epidural cerebral compression model, dendritic spines on the more superficial-lying layer III pyramidal neurons were found quickly reduced in 12hours, while those on the deep-located layer V pyramidal neurons were reduced slightly later, starting 1day following compression. No change in the synaptic vesicle markers synaptophysin and vesicular glutamate transporter 1 suggest no change in afferents. Postsynaptically, N-methyl-D-aspartate (NMDA) receptor trafficking to synaptic membrane was detected in 10minutes and lasting to 1day after compression. Translocation of calcineurin to synapses and enhancement of its enzymatic activity were detected within 10minutes as well. These suggest that compression rapidly activated NMDA receptors to increase postsynaptic calcium, which then activated the phosphatase calcineurin. In line with this, dephosphorylation and activation of the actin severing protein cofilin, and the consequent depolymerization of actin were all identified in the compressed cortex within matching time frames. Antagonizing NMDA receptors with MK801 before compression prevented t...
Source: Experimental Neurology - Category: Neurology Authors: Tags: Exp Neurol Source Type: research