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Protective effect of bradykinin against glutamate neurotoxicity in cultured rat retinal neurons.
- Source :
-
Investigative ophthalmology & visual science [Invest Ophthalmol Vis Sci] 2000 Jul; Vol. 41 (8), pp. 2273-8. - Publication Year :
- 2000
-
Abstract
- Purpose: To identify the localization and expression of bradykinin (BK)-B2 receptors in rat retina and examine the effects of BK on glutamate-induced neurotoxicity using cultured rat retinal neurons.<br />Methods: An immunohistochemical study using a specific antibody against BK-B2 receptor was performed with rat retina. Primary cultures were obtained from the retina of fetal rats (gestation day 17-19). Expression of BK-B2 receptor mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR) using total RNA obtained from cultured retinal neurons. Cultured cells were exposed to glutamate (1 mM) for 10 minutes and followed by incubation in glutamate-free medium for 1 hour. The effects of BK were assessed by simultaneous application of BK with glutamate. The neurotoxic effects on retinal cultures were quantitatively assessed by the trypan blue exclusion method.<br />Results: Immunohistochemical study demonstrated that BK-B2 receptors were expressed in the ganglion cell, inner nuclear layers, and outer nuclear layers. Furthermore, BK-B2 receptor mRNA expression was observed in cultured retinal neurons. Cell viability was markedly reduced by 10-minute exposure to 1 mM glutamate followed by a 1-hour incubation in glutamate-free medium. Simultaneous application of BK at concentrations of 0.001 to 1 microM with glutamate demonstrated dose-dependent protection against glutamate neurotoxicity. The protective action of BK (1 microM) was inhibited by simultaneous application of BK-B2 receptor antagonist, Hoe140 (1 microM). Furthermore, 1 microM BK had protective effects on neurotoxicity induced by 1 microM ionomycin, a calcium ionophore, and sodium nitroprusside (SNP, 500 microM), a nitric oxide (NO)-generating agent. However, BK did not inhibit neurotoxicity induced by 3-morpholinosydnonimine (SIN-1, 10 microM), an NO and oxygen radical donor.<br />Conclusions: These results suggest that BK-B2 receptors were distributed in rat retinas and cultured retinal neurons and that BK had a protective action against glutamate neurotoxicity through BK-B2 receptors in cultured retinal neurons. It is suggested that BK-induced protection against glutamate neurotoxicity took place downstream to NO generation and upstream to oxygen radical generation.
- Subjects :
- Adrenergic beta-Antagonists pharmacology
Animals
Bradykinin Receptor Antagonists
Cell Survival
Cells, Cultured
Dose-Response Relationship, Drug
Electrophoresis, Agar Gel
Ionomycin toxicity
Molsidomine toxicity
Neurons cytology
Neurons metabolism
Nitroprusside toxicity
RNA, Messenger biosynthesis
Rats
Rats, Wistar
Receptor, Bradykinin B2
Receptors, Bradykinin biosynthesis
Receptors, Bradykinin genetics
Retina cytology
Retina metabolism
Reverse Transcriptase Polymerase Chain Reaction
Bradykinin analogs & derivatives
Bradykinin pharmacology
Glutamic Acid toxicity
Molsidomine analogs & derivatives
Neurons drug effects
Neuroprotective Agents pharmacology
Retina drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0146-0404
- Volume :
- 41
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- Investigative ophthalmology & visual science
- Publication Type :
- Academic Journal
- Accession number :
- 10892873