Modulation of presynaptic calcium transients by metabotropic glutamate receptor activation: a differential role in acute depression of synaptic transmission and long-term depression.
J Neurosci
; 22(16): 6885-90, 2002 Aug 15.
Article
en En
| MEDLINE
| ID: mdl-12177186
ABSTRACT
Activation of group I metabotropic glutamate receptors (mGluRs) can induce acute depression of excitatory synaptic transmission and long-term depression (LTD) in area CA1 of the rat hippocampus. The underlying mechanisms for both forms of depression are unknown. By measuring presynaptic calcium transients, we show that a reduction in the stimulation-induced presynaptic calcium rise that triggers vesicular release causes the acute depression of transmission by group I mGluRs. In contrast, the mechanism underlying mGluR-induced LTD does not involve a persistent change in stimulation-induced calcium influx. However, analysis of paired-pulse facilitation experiments suggests a presynaptic location for expression of this form of LTD. Furthermore, we show that mGluR-induced LTD can be completely blocked by a specific mGluR5 antagonist, whereas mGluR1 antagonists strongly attenuate the acute depression of transmission. These results support the hypothesis that the acute depression of transmission caused by activation of group I mGluRs involves regulation of stimulation-induced presynaptic calcium transients, whereas mGluR-induced LTD involves a distinct presynaptic modulation downstream of calcium influx.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fura-2
/
Receptores de Glutamato Metabotrópico
/
Terminales Presinápticos
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Transmisión Sináptica
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Señalización del Calcio
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Inhibición Neural
Límite:
Animals
Idioma:
En
Revista:
J Neurosci
Año:
2002
Tipo del documento:
Article
País de afiliación:
Estados Unidos