Median lifetime of filopodia on pyramidal neuron in hippocampus

Range ~10 min
Organism Rat Rattus norvegicus
Reference Dailey, M.E. and Smith, S.J (1996) The dynamics of dendritic structure in developing hippocampal slices. J. Neurosci., 16: 2983-2994. abstract, p.2985 right column 2nd paragraph & p.2992 right column bottom paragraphPubMed ID8622128
Method Abstract:"Time-lapse fluorescence confocal microscopy was used to directly visualize the formation and dynamics of postsynaptic target structures (i.e., dendritic branches and spines) on pyramidal neurons within developing tissue slices. Within a 2 week period of time, pyramidal neurons in cultured slices derived from early postnatal rat (postnatal days 2-7) developed complex dendritic arbors bearing numerous postsynaptic spines."
Comments Abstract:"At early stages (1-2 d in vitro), many fine filopodial protrusions on dendrite shafts rapidly extended (maximum rate approximately 2.5 microM/minute) and retracted (median filopodial lifetime, 10 min), but some filopodia transformed into growth cones and nascent dendrite branches." p.2985 right column 2nd paragraph:"Motile protrusions were not confined to the tips of growing branches: lateral filopodia and growth cone-like sprouts were commonly seen along developing dendrite shafts. Most of the filopodial protrusions (up to 10 μm long) extended (maximal rate: ∼2.5 μm/min) from dendrite shafts, then retracted back to the shaft within 30 min or less (median lifetime, 10 min) (Fig. 2 B,C). Filopodia emerged from many different sites along the longitudinal extent of the apical and basal dendrites, although “hot spots” of filopodial protrusion were occasionally seen where filopodia repeatedly emerged and retracted from a localized site." p.2992 right column bottom paragraph:"The abundance of dendritic protrusive motions observed in [investigators’] studies supports the hypothesis (Saito et al., 1992) that dendrites are active partners in the initiation of synaptogenic cell–cell contacts, not merely passive targets for axonal exploration. The relatively short lifetimes (∼10 min) of most of the filopodia at early stages in development also suggest that any single image (e.g., from a fixed tissue specimen) would drastically under-represent the total number of filopodial eruptions that would occur during a typical developmental synaptogenesis period extending over several days."
Entered by Uri M
ID 112043