TY - JOUR T1 - Synaptic Vesicle Depletion Correlates with Attenuated Synaptic Responses to Prolonged Repetitive Stimulation in Mice Lacking α-Synuclein JF - The Journal of Neuroscience JO - J. Neurosci. SP - 8797 LP - 8807 DO - 10.1523/JNEUROSCI.22-20-08797.2002 VL - 22 IS - 20 AU - Deborah E. Cabin AU - Kazuhiro Shimazu AU - Diane Murphy AU - Nelson B. Cole AU - Wolfram Gottschalk AU - Kellie L. McIlwain AU - Bonnie Orrison AU - Amy Chen AU - Christopher E. Ellis AU - Richard Paylor AU - Bai Lu AU - Robert L. Nussbaum Y1 - 2002/10/15 UR - http://www.jneurosci.org/content/22/20/8797.abstract N2 - Although the mutation of α-synuclein, a protein associated with presynaptic vesicles, is implicated in the etiology and pathogenesis of Parkinson's disease, the biological function of the normal protein is unknown. Mice that lack α-synuclein have been generated by homologous recombination in embryonic stem cells. Electron microscopic examination of hippocampal synapses revealed a striking selective deficiency of undocked vesicles without affecting docked vesicles. Field recording of CA1 synapses in hippocampal slices from the mutant mice demonstrated normal basal synaptic transmission, paired-pulse facilitation, and response to a brief train of high-frequency stimulation (100 Hz, 40 pulses) that exhausts only docked vesicles. In contrast, the α-synuclein knock-out mice exhibited significant impairments in synaptic response to a prolonged train of repetitive stimulation (12.5 Hz, 300 pulses) capable of depleting docked as well as reserve pool vesicles. Moreover, the replenishment of the docked vesicles by reserve pool vesicles after depletion was slower in the mutant synapses. Thus, α-synuclein may be required for the genesis and/or maintenance of a subset of presynaptic vesicles, those in the “reserve” or “resting” pools. These results reveal, for the first time, the normal function of endogenous α-synuclein in regulating synaptic vesicle mobilization at nerve terminals. ER -