INVESTIGADORES
CAPANI Francisco
congresos y reuniones científicas
Título:
Localization of actin in rat pinceau.
Autor/es:
BOBIK, M., CAPANI, F.; ELLISMAN, M. H. ; MARTONE, M. E.
Lugar:
New Orleans
Reunión:
Congreso; Society for Neuroscience Meeting; 2000
Resumen:
The pinceau is a cerebellar structure formed by basket cell (BC) axon collaterals converging on the Purkinje cell axon initial segment (PCIS). In a previous study on the distribution of F-actin in the rat brain (Capani et al., submitted), we noted that the pinceau area was particularly enriched in F-actin. To determine the cellular elements stained for F-actin, we employed correlated light and electron microscopy (EM) using phalloidin-eosin, followed by fluorescence photooxidation. Three-dimensional EM analysis using electron tomography established the presence of actin in BC axons, particularly in those regions with high density of synaptic vesicles. Some astrocytes enveloping the PCIS and soma were also positive for actin. The most intense staining was found in thin fibers, 0.15ìm in diameter, that coursed through the pinceau region. These fibers had some characteristics of astrocytic processes, but lacked velous extensions. We further studied the distribution of F-actin using multilabel confocal microscopy. Actin labeling showed almost complete colocalization with PSD95, and with the potassium channel subunit Kv 3.2. Actin partially colocalized with GFAP, but rarely colocalized with neurofilament protein, which stains the main axons of pinceau fibers. Our results suggest that the terminal portions of pinceau fibers and some astrocytic processes are characterized by high concentrations of F-actin. The identity of the intensely stained processes remains to be determined. Because actin plays a major role in cell motility and maintaining cell architecture, the presence of high concentrations of F-actin in pinceau raises the possibility that this region is more dynamic than previously suspected.