Glucose and lactate are equally effective in energizing activity-dependent synaptic vesicle turnover in purified cortical neurons.
Neuroscience
; 141(1): 157-65, 2006 Aug 11.
Article
en En
| MEDLINE
| ID: mdl-16713114
ABSTRACT
This study examines the role of glucose and lactate as energy substrates to sustain synaptic vesicle cycling. Synaptic vesicle turnover was assessed in a quantitative manner by fluorescence microscopy in primary cultures of mouse cortical neurons. An electrode-equipped perfusion chamber was used to stimulate cells both by electrical field and potassium depolarization during image acquisition. An image analysis procedure was elaborated to select in an unbiased manner synaptic boutons loaded with the fluorescent dye N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl)pyridinium dibromide (FM1-43). Whereas a minority of the sites fully released their dye content following electrical stimulation, others needed subsequent K(+) depolarization to achieve full release. This functional heterogeneity was not significantly altered by the nature of metabolic substrates. Repetitive stimulation sequences of FM1-43 uptake and release were then performed in the absence of any metabolic substrate and showed that the number of active sites dramatically decreased after the first cycle of loading/unloading. The presence of 1 mM glucose or lactate was sufficient to sustain synaptic vesicle cycling under these conditions. Moreover, both substrates were equivalent for recovery of function after a phase of decreased metabolic substrate availability. Thus, lactate appears to be equivalent to glucose for sustaining synaptic vesicle turnover in cultured cortical neurons during activity.
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Base de datos:
MEDLINE
Asunto principal:
Vesículas Sinápticas
/
Corteza Cerebral
/
Ácido Láctico
/
Glucosa
/
Neuronas
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
Neuroscience
Año:
2006
Tipo del documento:
Article
País de afiliación:
Suiza