Modulation of GABAergic transmission in the cerebellar stellate cell network by neurotransmitter spillover and synaptic cross talk

Cerebellar stellate cells are interconnected interneurons located in the outer molecular layer. They provide inhibition to Purkinje cells, thereby modulating the final output of the cerebellum. In this work, electrophysiological means were employed to study the stellate cell network at the single synapse level. Sustained excitatory input invading the molecular layer was found to depress the chemical transmission between stellate cells, due to a decrease in the release probability of the inhibitory neurotransmitter ?-Aminobutyric acid (GABA). Analysis of synaptic parameters combined with the application of pharmacological tools indicated the involvement of metabotropic GABAB receptors and ionotropic L-?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-receptors localized in the axon of stellate cells. Ca2+ imaging experiments performed with Two-photon Microscopy confirmed the role of presynaptic receptors in affecting the axonal Ca2+ signals that trigger GABA release. These findings support the relevance of presynaptic receptors and provide another example of neurotransmitter spillover and cross talk between synapses, enriching the scenario of signal transmission at central synapses.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Heidelberg

Year

2006

Author dc:creator

• Astori, Simone

Contributors dc:contributor

• Köhr, Georg

Repository record source_url

http://www.ub.uni-heidelberg.de/archiv/7032

OAI identifier oai:identifier

oai:archiv.ub.uni-heidelberg.de:7032