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Functional Characterization of a Vesicular Glutamate Transporter in an Interneuron That Makes Excitatory and Inhibitory Synaptic Connections in a Molluscan Neural Circuit
- Source :
- Journal of Neuroscience. 35:9137-9149
- Publication Year :
- 2015
- Publisher :
- Society for Neuroscience, 2015.
-
Abstract
- Understanding circuit function requires the characterization of component neurons and their neurotransmitters. Previous work on radula protraction in the Aplysia feeding circuit demonstrated that critical neurons initiate feeding via cholinergic excitation. In contrast, it is less clear how retraction is mediated at the interneuronal level. In particular, glutamate involvement was suggested, but was not directly confirmed. Here we study a suspected glutamatergic retraction interneuron, B64. We used the representational difference analysis (RDA) method to successfully clone an Aplysia vesicular glutamate transporter (ApVGLUT) from B64 and from a glutamatergic motor neuron B38. Previously, RDA was used to characterize novel neuropeptides. Here we demonstrate its utility for characterizing other types of molecules. Bioinformatics suggests that ApVGLUT is more closely related to mammalian VGLUTs than to Drosophila and Caenorhabditis elegans VGLUTs. We expressed ApVGLUT in a cell line, and demonstrated that it indeed transports glutamate in an ATP and proton gradient-dependent manner. We mapped the ApVGLUT distribution in the CNS using in situ hybridization and immunocytochemistry. Further, we demonstrated that B64 is ApVGLUT positive, supporting the idea that it is glutamatergic. Although glutamate is primarily an excitatory transmitter in the mammalian CNS, B64 elicits inhibitory PSPs in protraction neurons to terminate protraction and excitatory PSPs in retraction neurons to maintain retraction. Pharmacological data indicated that both types of PSPs are mediated by glutamate. Thus, glutamate mediates the dual function of B64 in Aplysia. More generally, our systematic approaches based on RDA may facilitate analyses of transmitter actions in small circuits with identifiable neurons.
- Subjects :
- Male
Vesicular Glutamate Transport Proteins
Interneuron
Biology
Inhibitory postsynaptic potential
Glutamatergic
Interneurons
Aplysia
Chlorocebus aethiops
medicine
Animals
Phylogeny
General Neuroscience
Glutamate receptor
Excitatory Postsynaptic Potentials
Articles
Motor neuron
biology.organism_classification
medicine.anatomical_structure
Inhibitory Postsynaptic Potentials
nervous system
COS Cells
Excitatory postsynaptic potential
Female
Nerve Net
Neuroscience
Subjects
Details
- ISSN :
- 15292401 and 02706474
- Volume :
- 35
- Database :
- OpenAIRE
- Journal :
- Journal of Neuroscience
- Accession number :
- edsair.doi.dedup.....9a8a67c21a539d0ad7e2522d757f8c4f