%A Hasegawa,Yoshitaka %A Mukai,Hideo %A Asashima,Makoto %A Hojo,Yasushi %A Ikeda,Muneki %A Komatsuzaki,Yoshimasa %A Ooishi,Yuuki %A Kawato,Suguru %D 2014 %J Frontiers in Neural Circuits %C %F %G English %K Hippocampus,activin,Spine,LTP,synapse,rapid effect,kinase %Q %R 10.3389/fncir.2014.00056 %W %L %M %P %7 %8 2014-June-02 %9 Original Research %+ Prof Suguru Kawato,Bioinformatics Project (BIRD), Japan Science and Technology Agency, The University of Tokyo,Meguro, Japan,kawato@phys.c.u-tokyo.ac.jp %+ Prof Suguru Kawato,Core Research for Evolutional Science and Technology Project of Japan Science and Technology Agency, The University of Tokyo,Meguro, Japan,kawato@phys.c.u-tokyo.ac.jp %+ Prof Suguru Kawato,Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo,Meguro, Japan,kawato@phys.c.u-tokyo.ac.jp %+ Prof Suguru Kawato,National MEXT Project in Special Coordinate Funds for Promoting Science and Technology, The University of Tokyo,Meguro, Japan,kawato@phys.c.u-tokyo.ac.jp %# %! Acute Modulation of Synaptic Plasticity by Activin in Hippocampus %* %< %T Acute modulation of synaptic plasticity of pyramidal neurons by activin in adult hippocampus %U https://www.frontiersin.org/articles/10.3389/fncir.2014.00056 %V 8 %0 JOURNAL ARTICLE %@ 1662-5110 %X Activin A is known as a neuroprotective factor produced upon acute excitotoxic injury of the hippocampus (in pathological states). We attempt to reveal the role of activin as a neuromodulator in the adult male hippocampus under physiological conditions (in healthy states), which remains largely unknown. We showed endogenous/basal expression of activin in the hippocampal neurons. Localization of activin receptors in dendritic spines (=postsynapses) was demonstrated by immunoelectron microscopy. The incubation of hippocampal acute slices with activin A (10 ng/mL, 0.4 nM) for 2 h altered the density and morphology of spines in CA1 pyramidal neurons. The total spine density increased by 1.2-fold upon activin treatments. Activin selectively increased the density of large-head spines, without affecting middle-head and small-head spines. Blocking Erk/MAPK, PKA, or PKC prevented the activin-induced spinogenesis by reducing the density of large-head spines, independent of Smad-induced gene transcription which usually takes more than several hours. Incubation of acute slices with activin for 2 h induced the moderate early long-term potentiation (moderate LTP) upon weak theta burst stimuli. This moderate LTP induction was blocked by follistatin, MAPK inhibitor (PD98059) and inhibitor of NR2B subunit of NMDA receptors (Ro25-6981). It should be noted that the weak theta burst stimuli alone cannot induce moderate LTP. These results suggest that MAPK-induced phosphorylation of NMDA receptors (including NR2B) may play an important role for activin-induced moderate LTP. Taken together, the current results reveal interesting physiological roles of endogenous activin as a rapid synaptic modulator in the adult hippocampus.