Synapsin regulates Basal synaptic strength, synaptic depression, and serotonin-induced facilitation of sensorimotor synapses in Aplysia.
Synapsin is a synaptic vesicle-associated protein implicated in the regulation of vesicle trafficking and transmitter release, but its role in heterosynaptic plasticity remains elusive. Moreover, contradictory results have obscured the contribution of synapsin to homosynaptic plasticity. We previously reported that the neuromodulator serotonin (5-HT) led to the phosphorylation and redistribution of Aplysia synapsin, suggesting that synapsin may be a good candidate for the regulation of vesicle mobilization underlying the short-term synaptic plasticity induced by 5-HT. This study examined the role of synapsin in homosynaptic and heterosynaptic plasticity. Overexpression of synapsin reduced basal transmission and enhanced homosynaptic depression. Although synapsin did not affect spontaneous recovery from depression, it potentiated 5-HT-induced dedepression. Computational analysis showed that the effects of synapsin on plasticity could be adequately simulated by altering the rate of Ca(2+)-dependent vesicle mobilization, supporting the involvement of synapsin not only in homosynaptic but also in heterosynaptic forms of plasticity by regulating vesicle mobilization.
Fioravante
Diasinou
D
Department of Neurobiology and Anatomy, W M Keck Ctr for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, TX 77225, USA.
Liu
Rong-Yu
RY
Netek
Anne K
AK
Cleary
Leonard J
LJ
Byrne
John H
JH
D000818:Animals; D001048:Aplysia / Q000502:physiology*; D018920:Coculture Techniques; D003198:Computer Simulation; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004594:Electrophysiology; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D009046:Motor Neurons / Q000187:drug effects; D009473:Neuronal Plasticity / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects; D018408:Patch-Clamp Techniques; D010957:Plasmids / Q000235:genetics; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012701:Serotonin / Q000494:pharmacology*; D013569:Synapses / Q000187:drug effects* / Q000502:physiology*; D016704:Synapsins / Q000235:genetics / Q000502:physiology*; D013572:Synaptic Vesicles / Q000187:drug effects / Q000648:ultrastructure
C092350:FM 4-64; D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D016704:Synapsins; D012701:Serotonin; D017868:Cyclic AMP-Dependent Protein Kinases