Synapsin- and actin-dependent frequency enhancement in mouse hippocampal mossy fiber synapses. / Owe, Simen G.; Jensen, Vidar; Evergren, Emma; Ruiz, Arnaud; Shupliakov, Oleg; Kullmann, Dimitri M.; Storm-Mathisen, Jon; Walaas, S. Ivar; Hvalby, Øivind; Bergersen, Linda H.
In: Cerebral Cortex, Vol. 19, No. 3, 01.03.2009, p. 511-523.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Synapsin- and actin-dependent frequency enhancement in mouse hippocampal mossy fiber synapses
AU - Owe, Simen G.
AU - Jensen, Vidar
AU - Evergren, Emma
AU - Ruiz, Arnaud
AU - Shupliakov, Oleg
AU - Kullmann, Dimitri M.
AU - Storm-Mathisen, Jon
AU - Walaas, S. Ivar
AU - Hvalby, Øivind
AU - Bergersen, Linda H.
PY - 2009/3/1
Y1 - 2009/3/1
N2 - The synapsin proteins have different roles in excitatory and inhibitory synaptic terminals. We demonstrate a differential role between types of excitatory terminals. Structural and functional aspects of the hippocampal mossy fiber (MF) synapses were studied in wild-type (WT) mice and in synapsin double-knockout mice (DKO). A severe reduction in the number of synaptic vesicles situated more than 100 nm away from the presynaptic membrane active zone was found in the synapsin DKO animals. The ultrastructural level gave concomitant reduction in F-actin immunoreactivity observed at the periactive endocytic zone of the MF terminals. Frequency facilitation was normal in synapsin DKO mice at low firing rates (∼0.1 Hz) but was impaired at firing rates within the physiological range (∼2 Hz). Synapses made by associational/commissural fibers showed comparatively small frequency facilitation at the same frequencies. Synapsin-dependent facilitation in MF synapses of WT mice was attenuated by blocking F-actin polymerization with cytochalasin B in hippocampal slices. Synapsin III, selectively seen in MF synapses, is enriched specifically in the area adjacent to the synaptic cleft. This may underlie the ability of synapsin III to promote synaptic depression, contributing to the reduced frequency facilitation observed in the absence of synapsins I and II.
AB - The synapsin proteins have different roles in excitatory and inhibitory synaptic terminals. We demonstrate a differential role between types of excitatory terminals. Structural and functional aspects of the hippocampal mossy fiber (MF) synapses were studied in wild-type (WT) mice and in synapsin double-knockout mice (DKO). A severe reduction in the number of synaptic vesicles situated more than 100 nm away from the presynaptic membrane active zone was found in the synapsin DKO animals. The ultrastructural level gave concomitant reduction in F-actin immunoreactivity observed at the periactive endocytic zone of the MF terminals. Frequency facilitation was normal in synapsin DKO mice at low firing rates (∼0.1 Hz) but was impaired at firing rates within the physiological range (∼2 Hz). Synapses made by associational/commissural fibers showed comparatively small frequency facilitation at the same frequencies. Synapsin-dependent facilitation in MF synapses of WT mice was attenuated by blocking F-actin polymerization with cytochalasin B in hippocampal slices. Synapsin III, selectively seen in MF synapses, is enriched specifically in the area adjacent to the synaptic cleft. This may underlie the ability of synapsin III to promote synaptic depression, contributing to the reduced frequency facilitation observed in the absence of synapsins I and II.
KW - Actin filaments
KW - Frequency facilitation
KW - Hippocampal synapses
KW - Immunoelectron microscopy
KW - Presynaptic plasticity
UR - http://www.scopus.com/inward/record.url?scp=59749083595&partnerID=8YFLogxK
U2 - 10.1093/cercor/bhn101
DO - 10.1093/cercor/bhn101
M3 - Article
C2 - 18550596
AN - SCOPUS:59749083595
VL - 19
SP - 511
EP - 523
JO - Cerebral Cortex
JF - Cerebral Cortex
SN - 1047-3211
IS - 3
ER -
ID: 40831084