The identification of vesicular glutamate transporter 3 suggests novel modes of signaling by glutamate

Abstract

Quantal release of the principal excitatory neurotransmitter glutamate requires a mechanism for its transport into secretory vesicles. Within the brain, the complementary expression of vesicular glutamate transporters (VGLUTs) 1 and 2 accounts for the release of glutamate by all known excitatory neurons. We now report the identification of VGLUT3 and its expression by many cells generally considered to release a classical transmitter with properties very different from glutamate. Remarkably, subpopulations of inhibitory neurons as well as cholinergic interneurons, monoamine neurons, and glia express VGLUT3. The dendritic expression of VGLUT3 by particular neurons also indicates the potential for retrograde synaptic signaling. The distribution and subcellular location of VGLUT3 thus suggest novel modes of signaling by glutamate.

Vesicular glutamate transporter 3-immunoreactive pericellular baskets ensheath a distinct population of neurons in the lateral septum

“…In the basal forebrain, axonal co-expression of VGLUT3-immunoreactivity was shown for the striatal cholinergic interneurons. In contrast, the VGLUT3-ir fibrous structures in the LS did not co-express acetylcholine, serotonin and, only rarely, GABA (Fremeau et al, 2002;Gras et al, 2002;Herzog et al, 2004).…”

Expression of c-Fos in arcuate nucleus induced by electroacupuncture: Relations to neurons containing opioids and glutamate

“…VGLUT3 is considered to be a marker for neurons that contain glutamate (Fremeau et al, 2002;Gritti et al, 2006;Guo et al, 2005). In this respect, Gritti et al have shown that almost all (96-100%) VGLUT3-labeled neurons are positively stained for phosphate-activated glutaminase (pGlu), an enzyme that synthesizes glutamate from glutamine, and that approximately 70% of pGlucontaining neurons are co-labeled with VGLUT3.…”

“…Triple-fluorescent immunohistochemical labels for c-Fos, glutamate, and β-endorphin-Currently, vesicular glutamate transporter 3 (VGLUT3), present in perikarya as well as neuronal processes, has been employed to identify neurons that use glutamate as a neurotransmitter (Fremeau et al, 2002;Gritti et al, 2006;Guo et al, 2005). Thus, we stained VGLUT3 to detect glutamatergic neurons.…”

Vesicular Glutamate Transporter 2 Is Associated with the Cochlear Nucleus Commissural Pathway

“…VGLUTs accumulate glutamate in synaptic vesicles and are prime markers for excitatory glutamatergic terminals (Fremeau et al 2002(Fremeau et al , 2001Gabellec et al 2007;Kaneko et al 2002;Zhou et al 2007). In addition, we conducted retrograde tract tracing experiments combined with immunohistochemical identification of glycine and GABA to identify which CN-commissural neurons were not inhibitory.…”