TY - JOUR
T1 - Ampa receptor subunit glur1 (glua1) serine-845 site is involved in synaptic depression but not in spine shrinkage associated with chemical long-term depression
AU - He, Kaiwen
AU - Lee, Angela
AU - Song, Lihua
AU - Kanold, Patrick O.
AU - Lee, Hey Kyoung
PY - 2011/4
Y1 - 2011/4
N2 - The structure of dendritic spines is highly plastic and can be modified by neuronal activity. In addition, there is evidence that spine head size correlates with the synaptic α-amino-3-hydroxy-5-methylisoxazole propionic acid (AMPA) receptor (AMPAR) content, which suggests that they may be coregulated. Although there is evidence that there are overlapping mechanisms for structural and functional plasticity, the extent of the overlap needs further investigation. Specifically, it is unknown whether AMPAR levels determine spine size or whether both are regulated via parallel pathways. We studied the correlation between spine structural plasticity and long-term synaptic plasticity following chemical-induced long-term depression (chemLTD). In particular, we examined whether the regulation of AMPARs, which is implicated in LTD, is critical for spine morphological plasticity. We used mutant mice specifically lacking the serine-845 site on the type 1 glutamate receptor (GluR1, or GluA1) subunit of AMPARs (mutants). These mice specifically lack N-methyl-D-aspartate (NMDA) receptor (NMDAR)-dependent LTD and NMDAR activation-induced AMPAR endocytosis. We found that chemLTD causes a rapid and persistent shrinkage in spine head volume of hippocampal CA1 pyramidal neurons in wild types similar to that reported in other studies using low-frequency stimulation (LFS)-induced LTD. Surprisingly, we found that although S845A mutant mice display impaired chemLTD, the shrinkage of spine head volume occurred to a similar magnitude to that observed in wild types. Our results suggest that there is dissociation in the molecular mechanisms underlying functional LTD and spine shrinkage and that GluR1-S845 regulation is not necessary for spine morphological plasticity.
AB - The structure of dendritic spines is highly plastic and can be modified by neuronal activity. In addition, there is evidence that spine head size correlates with the synaptic α-amino-3-hydroxy-5-methylisoxazole propionic acid (AMPA) receptor (AMPAR) content, which suggests that they may be coregulated. Although there is evidence that there are overlapping mechanisms for structural and functional plasticity, the extent of the overlap needs further investigation. Specifically, it is unknown whether AMPAR levels determine spine size or whether both are regulated via parallel pathways. We studied the correlation between spine structural plasticity and long-term synaptic plasticity following chemical-induced long-term depression (chemLTD). In particular, we examined whether the regulation of AMPARs, which is implicated in LTD, is critical for spine morphological plasticity. We used mutant mice specifically lacking the serine-845 site on the type 1 glutamate receptor (GluR1, or GluA1) subunit of AMPARs (mutants). These mice specifically lack N-methyl-D-aspartate (NMDA) receptor (NMDAR)-dependent LTD and NMDAR activation-induced AMPAR endocytosis. We found that chemLTD causes a rapid and persistent shrinkage in spine head volume of hippocampal CA1 pyramidal neurons in wild types similar to that reported in other studies using low-frequency stimulation (LFS)-induced LTD. Surprisingly, we found that although S845A mutant mice display impaired chemLTD, the shrinkage of spine head volume occurred to a similar magnitude to that observed in wild types. Our results suggest that there is dissociation in the molecular mechanisms underlying functional LTD and spine shrinkage and that GluR1-S845 regulation is not necessary for spine morphological plasticity.
KW - Dendritic
KW - α-amino-3-hydroxy-5-methylisoxazole propionic acid receptor
UR - http://www.scopus.com/inward/record.url?scp=79955130334&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79955130334&partnerID=8YFLogxK
U2 - 10.1152/jn.00913.2010
DO - 10.1152/jn.00913.2010
M3 - Article
C2 - 21307330
AN - SCOPUS:79955130334
VL - 105
SP - 1897
EP - 1907
JO - Journal of Neurophysiology
JF - Journal of Neurophysiology
SN - 0022-3077
IS - 4
ER -