beta-Phorbol ester-induced enhancement of exocytosis in large mossy fiber boutons of mouse hippocampus

beta-Phorbol esters (BPE), synthetic analogues of diacylglycerol (DAG), induce the potentiation of transmission in many kinds of synapses through activating the C(1) domain-containing receptors. However, their effects on synaptic vesicle exocytosis have not yet been investigated. Here, we evaluated...

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Bibliographic Details
Published in:The journal of physiological sciences 2009-07, Vol.59 (4), p.263-274
Main Authors: Hikima, Takuya, Araki, Rikita, Ishizuka, Toru, Yawo, Hiromu
Format: Article
Language:English
Subjects:
Animals
Calcium - metabolism
Excitatory Postsynaptic Potentials - drug effects
Exocytosis - drug effects
Green Fluorescent Proteins - genetics
Green Fluorescent Proteins - metabolism
In Vitro Techniques
Mice
Mice, Inbred C57BL
Mice, Transgenic
Mossy Fibers, Hippocampal - drug effects
Mossy Fibers, Hippocampal - physiology
Original Paper
Phorbol Esters - pharmacology
Presynaptic Terminals - drug effects
Presynaptic Terminals - physiology
Recombinant Fusion Proteins - genetics
Recombinant Fusion Proteins - metabolism
Staurosporine - pharmacology
Synaptic Transmission - drug effects
Citations: Items that this one cites
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Summary:beta-Phorbol esters (BPE), synthetic analogues of diacylglycerol (DAG), induce the potentiation of transmission in many kinds of synapses through activating the C(1) domain-containing receptors. However, their effects on synaptic vesicle exocytosis have not yet been investigated. Here, we evaluated the vesicular exocytosis directly from individual large mossy fiber boutons (LMFBs) in hippocampal slices from transgenic mice that selectively express synaptopHluorin (SpH). We found that the activity-dependent increment of SpH fluorescence (DeltaSpH) was enhanced by 4beta-phorbol 12,13-diacetate (PDAc), one of the BPEs, without influencing the recycled component of SpH. These PDAc effects on DeltaSpH were almost completely inhibited by staurosporine, a non-selective antagonist of protein kinases. However, intermittent synaptic transmission was still potentiated through a staurosporine-resistant mechanism. The staurosporine-sensitive cascade may facilitate the vesicle replenishment, thus maintaining the fidelity of transmission at a high level during repetitive firing of the presynaptic neuron.
ISSN:1880-6546
1880-6562
DOI:10.1007/s12576-009-0031-0