ABSTRACT
Vesicular glutamate transporters (VGLUT1-3) carry glutamate into synaptic vesicles. VGLUT3 has been reported to be localized in nonglutamatergic neuronal populations in the brain. However, detailed subcellular localization of VGLUT3 has not been shown. In particular, the identity of synaptic vesicles expressing VGLUT3 remains to be revealed. Here we present novel electron microscopic postembedding immunogold data from mouse and rat brains showing that small, clear, and round synaptic vesicles in γ-aminobutyric acid (GABA)-ergic nerve terminals contain labeling for both VGLUT3 and the vesicular GABA transporter (VGAT). Immunoisolation of synaptic vesicles confirmed the immunogold data and showed vesicular colocalization of VGLUT3 and VGAT. Moreover, we show that gold particles signaling VGLUT3 are present in synaptic vesicles in acetylcholinergic nerve terminals in the striatum. Quantitative immunogold analyses reveal that the density of VGLUT3 gold particles is similar in GABAergic terminals in the hippocampus and the neocortex to that in cholinergic terminals in the striatum. In contrast to in the hippocampus and the neocortex, VGLUT3 was absent from VGAT-positive terminals in the striatum. The labeling pattern produced by the VGLUT3 antibodies was found to be specific; there was no labeling in VGLUT3 knockout tissue, and the observed labeling throughout the rat brain corresponds to the known light-microscopic distribution of VGLUT3. From the present results, we infer that glutamate is released with GABA from inhibitory terminals and acetylcholine from cholinergic terminals.
Subject(s)
Amino Acid Transport Systems, Acidic/metabolism , Brain/metabolism , Vesicular Inhibitory Amino Acid Transport Proteins/metabolism , Amino Acid Transport Systems, Acidic/deficiency , Amino Acid Transport Systems, Acidic/ultrastructure , Animals , Brain/cytology , Choline O-Acetyltransferase/metabolism , Gene Expression Regulation/genetics , Green Fluorescent Proteins/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Microscopy, Immunoelectron , Rats , Rats, Wistar , Synaptic Vesicles/metabolism , Synaptic Vesicles/ultrastructure , Vesicular Inhibitory Amino Acid Transport Proteins/ultrastructureABSTRACT
BACKGROUND: Increased urine secretion of peptides has been found in celiac disease, probably resulting from increased intestinal uptake of peptides caused by damage to the small gut mucosa. METHODS: High-performance liquid chromatography of low-molecular-weight peptides in the urine was performed over 6 months, before and after a gluten-free diet was instituted in children who clinically improved while consuming the diet. RESULTS: A significant decrease of peptide levels was observed in children consuming the gluten-free diet. Certain peptide peaks thought to be gluten related decreased the most after the patients began the diet. CONCLUSIONS: Because the peptides decrease in patients consuming a gluten-free diet, it is reasonable to conclude that such peptides have a mostly dietary origin.
Subject(s)
Celiac Disease/diet therapy , Celiac Disease/urine , Glutens/administration & dosage , Peptides/urine , Adolescent , Child , Child, Preschool , Chromatography, High Pressure Liquid , Gliadin/urine , Glutens/urine , Humans , Molecular WeightSubject(s)
Peptides/urine , Schizophrenia/urine , Adolescent , Female , Humans , Male , Schizophrenia/diagnosisABSTRACT
BACKGROUND: In celiac disease, the mucosa in the small intestine is damaged. This study was conducted to determine whether the normal peptide and protein uptake from the gut is increased in patients with celiac disease. METHODS: The low-molecular-weight peptides were measured in urine from children and adults with untreated celiac disease. A reversed-phase technique was used. RESULTS: The excretion of peptides increased compared with that in an age- and sex-matched reference group. CONCLUSIONS: Celiac patients have hyperpeptiduria. It is possible that some of these peptides are bioactive and may mediate varying systemic effects also found in untreated celiac disease.