Synaptic vesicle mobility in mouse motor nerve terminals with and without synapsin.
We measured synaptic vesicle mobility using fluorescence recovery after photobleaching of FM 1-43 [N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide] stained mouse motor nerve terminals obtained from wild-type (WT) and synapsin triple knock-out (TKO) mice at room temperature and physiological temperature. Vesicles were mobile in resting terminals at physiological temperature but virtually immobile at room temperature. Mobility was increased at both temperatures by blocking phosphatases with okadaic acid, decreased at physiological temperature by blocking kinases with staurosporine, and unaffected by disrupting actin filaments with latrunculin A or reducing intracellular calcium concentration with BAPTA-AM. Synapsin TKO mice showed reduced numbers of synaptic vesicles and reduced FM 1-43 staining intensity. Synaptic transmission, however, was indistinguishable from WT, as was synaptic vesicle mobility under all conditions tested. Thus, in TKO mice, and perhaps WT mice, a phospho-protein different from synapsin but otherwise of unknown identity is the primary regulator of synaptic vesicle mobility.
Gaffield
Michael A
MA
Neuroscience Program, University of Colorado Medical School, Anschutz Medical Campus, Aurora, Colorado 80045, USA.
Betz
William J
WJ
D008841:Actin Cytoskeleton / Q000187:drug effects; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D036681:Fluorescence Recovery After Photobleaching; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009046:Motor Neurons / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D019319:Okadaic Acid / Q000494:pharmacology; D009924:Organ Culture Techniques; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors; D010770:Phosphotransferases / Q000037:antagonists & inhibitors; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D019311:Staurosporine / Q000494:pharmacology; D016704:Synapsins / Q000235:genetics / Q000378:metabolism*; D013572:Synaptic Vesicles / Q000378:metabolism*; D013696:Temperature; D053778:Thiazolidines / Q000494:pharmacology
D019086:Bridged Bicyclo Compounds, Heterocyclic; D004791:Enzyme Inhibitors; C073804:FM1 43; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D016704:Synapsins; D053778:Thiazolidines; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D019319:Okadaic Acid; D004533:Egtazic Acid; D010770:Phosphotransferases; D010744:Phosphoric Monoester Hydrolases; D019311:Staurosporine; C037067:latrunculin A; D002118:Calcium