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Updated: Jun 3, 2026

Vibrodissociation of Neurons from Rodent Brain Slices to Study Synaptic Transmission and Image Presynaptic Terminals
Published on: May 25, 2011
Biphasic action of axonal GABA-A receptors on presynaptic calcium influx
1Université Paris Descartes, Paris, France. brandon.stell@parisdescartes.fr
Abstract:
Although ionotropic γ-aminobutyric acid A receptors (GABA(A)Rs) have long been known to exist on the axons of many different cells, their effect on axon excitability and synaptic transmission remains controversial. Here, using high-speed Ca(2+) imaging, it is shown that they induce a biphasic effect in parallel fibers of the cerebellar cortex. Multicellular measurements indicate a facilitation of action potential (AP)-evoked Ca(2+) transients, which is subsequently followed by depression. However, the receptor activation does not increase influx of Ca(2+) into individual fibers but instead, increases the probability of AP generation. These results provide a description of the effect of presynaptic GABA(A)R activation and explain why reports of the effect of their activation have been so varied.
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