Effect of diabetes on levels and uptake of putative amino acid neurotransmitters in rat retina and retinal pigment epithelium

Vilchis, Carmen; Salceda, Rocı́o

doi:10.1007/bf02532391

Cited by 50 publications

(40 citation statements)

References 25 publications

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“…Li et al (37) reported an increased accumulation of extracellular glutamate in the neocortex submitted to hyperglycemic ischemia, which was correlated with the cell damage observed. In this study, we reported that diabetes had no effect on both synaptosomal GABA and glutamate transport, which is partially in accordance with the observations of Vilchis and Salceda (8). These authors demonstrated an increment in GABA uptake, without changes in glutamate uptake in diabetic rat retina and retinal pigment epithelium.…”

Section: Diabetes Vol 53 August 2004supporting

confidence: 92%

“…Several authors have shown that diabetes modifies the levels of free amino acids (7,8) and the accumulation of amino acid neurotransmitters. Vilchis and Salceda (8) reported an increase in taurine and ␥-aminobutyric acid (GABA) uptake, whereas glycine and glutamate uptake remained unaffected in diabetic rat retina and retinal pigment epithelium.…”

mentioning

confidence: 99%

“…Vilchis and Salceda (8) reported an increase in taurine and ␥-aminobutyric acid (GABA) uptake, whereas glycine and glutamate uptake remained unaffected in diabetic rat retina and retinal pigment epithelium. In a previous study performed in 6-month-old diabetic Goto-Kakizaki (GK) rat synaptosomes, we demonstrated a diabetes-induced decrease in glutamate accumulation, leading to the hypothesis that diabetes modifies glutamate transport and increases neuronal injury occurring under pathological conditions (3).…”

mentioning

confidence: 99%

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Oxidative Stress Affects Synaptosomal γ-Aminobutyric Acid and Glutamate Transport in Diabetic Rats

et al. 2004

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Evidence suggests that oxidative stress is involved in the pathophysiology of diabetic complications and that insulin has a neuroprotective role in oxidative stress conditions. In this study, we evaluated the in vitro effect of insulin in the susceptibility to oxidative stress and in the transport of the amino acid neurotransmitters ␥-aminobutyric acid (GABA) and glutamate in a synaptosomal fraction isolated from male type 2 diabetic Goto-Kakizaki (GK) rat brain cortex. The ascorbate/ Fe 2؉ -induced increase in thiobarbituric acid reactive substances (TBARSs) was similar in Wistar and GK rats and was not reverted by insulin (1 mol/l), suggesting that other mechanisms, rather than a direct effect in membrane lipid peroxidation, may mediate insulin neuroprotection. Diabetes did not affect GABA and glutamate transport, despite the significant decrease in membrane potential and ATP/ADP ratio, and insulin increased the uptake of both GABA and glutamate in GK rats. Upon oxidation, there was a decrease in the uptake of both neurotransmitters and an increase in extrasynaptosomal glutamate levels and in ATP/ADP ratio in GK rats. Insulin treatment reverted the ascorbate/Fe 2؉ -induced decrease in GABA accumulation, with a decrease in extrasynaptosomal GABA. These results suggest that insulin modulates synaptosomal GABA and/or glutamate transport, thus having a neuroprotective role under oxidizing and/or diabetic conditions.

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Section: Diabetes Vol 53 August 2004supporting

confidence: 92%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Oxidative Stress Affects Synaptosomal γ-Aminobutyric Acid and Glutamate Transport in Diabetic Rats

et al. 2004

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“…In addition, we could not detect any substantial increase in retinal taurine concentration in diabetic rats which were fed a taurine-supplemented diet. The retina has a remarkable capacity to maintain taurine concentration [77,78], and any access of retinal taurine is probably rapidly removed after the cessation of food intake.…”

Section: Discussionmentioning

confidence: 99%

Antioxidants attenuate early up regulation of retinal vascular endothelial growth factor in streptozotocin-diabetic rats

et al. 2001

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Aims/hypothesis. A strong positive correlation has been found between lipid peroxidation product and vascular endothelial growth factor concentrations in the vitreous of patients with proliferative diabetic retinopathy. To establish a causal relation between diabetes-associated enhanced oxidative stress and vascular endothelial growth factor production, we evaluated two antioxidants, dl-a-lipoic acid and taurine, on retinal vascular endothelial growth factor protein and mRNA expression and on parameters of oxidative stress in streptozotocin-diabetic rats. Methods. Our experiments were on control rats and streptozotocin-diabetic rats with a 6-week duration of diabetes, treated with or without dl-a-lipoic acid (100 mg´kg ±1´d±1 , i. p.) or taurine (1 % in the diet) starting from induction of diabetes. Vascular endothelial growth factor protein in retinal homogenates was assessed by sandwich ELISA with an affinity-purified polyclonal antibody and vascular endothelial growth factor mRNA by ribonuclease protection assay. Retinal lipid peroxidation products i. e. malondialdehyde plus 4-hydroxyalkenals were quantified with n-methyl-2-phenylindole. Retinal reduced and oxidized glutathione, ascorbate, dehydroascorbate, and sorbitol pathway intermediates were measured spectrofluorometrically, and taurine by reverse-phase HPLC.Results. Vascular endothelial growth factor protein concentration (means SD) was increased in diabetic rats compared with control rats (33 7 vs 19 5 pg/mg total protein, p < 0.01) This increase was attenuated by taurine (26 8, p < 0.05) and prevented by dla-lipoic acid (21 4, p < 0.01). Vascular endothelial growth factor mRNA abundance was reduced by 1.4-fold in diabetic rats compared with control rats and this decrease was attenuated but not completely prevented by both antioxidants. Malondialdehyde plus 4-hydroxyalkenal concentration was increased in diabetic rats compared with control rats, and both antioxidants arrested accumulation of lipid peroxidation products. Taurine, reduced glutathione, oxidized glutathione, ascorbate, dehydroascorbate and sorbitol pathway intermediate concentrations as well as oxidized glutathione/reduced glutathione and dehydroascorbate/ascorbate ratios were similar in control and diabetic rats treated with or without taurine. Conclusion/interpretation. Oxidative stress is directly involved in up regulation of vascular endothelial growth factor protein in the retina during early diabetes. [Diabetologia (2001

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“…One important diabetic complication, platelet hyperaggregation, has been normalized by the alteration of bile acids composition through the addition of taurine (Franconi et al 1995). Another complication is T1D retinopathy which have shown significantly less taurine levels in the retina, compared with that in healthy rats (Vilchis & Salceda 1996). Diabetic nephropathy are other major complication of T1D.…”

Section: Diabetes-associated Disturbances In Bile Acids and Gut Micromentioning

confidence: 99%

Potentials and Limitations of Bile Acids and Probiotics in Diabetes Mellitus

Mikov¹,

Al‐Salami²,

Goločorbin-Kon³

2011

Type 1 Diabetes - Complications, Pathogenesis, and Alternative Treatments

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Effect of diabetes on levels and uptake of putative amino acid neurotransmitters in rat retina and retinal pigment epithelium

Cited by 50 publications

References 25 publications

Oxidative Stress Affects Synaptosomal γ-Aminobutyric Acid and Glutamate Transport in Diabetic Rats

Oxidative Stress Affects Synaptosomal γ-Aminobutyric Acid and Glutamate Transport in Diabetic Rats

Antioxidants attenuate early up regulation of retinal vascular endothelial growth factor in streptozotocin-diabetic rats

Potentials and Limitations of Bile Acids and Probiotics in Diabetes Mellitus

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