Control of neurotransmitter release by an internal gel matrix in synaptic vesicles.
Proc Natl Acad Sci U S A
; 100(6): 3485-90, 2003 Mar 18.
Article
em En
| MEDLINE
| ID: mdl-12629223
ABSTRACT
Neurotransmitters are stored in synaptic vesicles, where they have been assumed to be in free solution. Here we report that in Torpedo synaptic vesicles, only 5% of the total acetylcholine (ACh) or ATP content is free, and that the rest is adsorbed to an intravesicular proteoglycan matrix. This matrix, which controls ACh and ATP release by an ion-exchange mechanism, behaves like a smart gel. That is, it releases neurotransmitter and changes its volume when challenged with small ionic concentration change. Immunodetection analysis revealed that the synaptic vesicle proteoglycan SV2 is the core of the intravesicular matrix and is responsible for immobilization and release of ACh and ATP. We suggest that in the early steps of vesicle fusion, this internal matrix regulates the availability of free diffusible ACh and ATP, and thus serves to modulate the quantity of transmitter released.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vesículas Sinápticas
/
Neurotransmissores
Limite:
Animals
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article