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Interactions between neomycin and cerebral dopaminergic and serotoninergic transmission in rats
1Department of Biology, Abdelmalek Essaâdi University, Morocco.
Abstract:
The aim of this work was to investigate the effects of neomycin on monoamine contents of rat striatal tissue. The analysis was performed by HPLC with electrochemical detection. Rats were injected with neomycin (2 mg/kg; i.p.) and killed at different times over 24 h. The striatal homogenate was injected in a reversed-phase HPLC. Results showed a significant increase in dopamine tissue level (+35 per cent; 4 h after neomycin injection) and a decrease (-36 per cent) in the level of its metabolites. Striatal serotonin level showed a rapid and significant (p < 0.001) increase, +130 per cent, 2 h after neomycin injection. DOPAC/DA and 5HIAA/5HT ratios were reduced by 34 per cent and 46 per cent respectively. These results indicate an inhibitory effect of neomycin on striatal dopaminergic and serotoninergic systems. Several mechanisms could be involved in these effects of neomycin in the biosynthesis process through stimulation of tyrosine hydroxylase and tryptophane hydroxylase and/or MAO and COMT activities. The blockage of calcium channels was also suggested.
Insights
Neomycin significantly alters dopamine and serotonin levels in rat brains, impacting neurotransmitter balance. This study reveals neomycin
Area of Science:
- Neuroscience
- Pharmacology
- Biochemistry
Background:
- Monoamine neurotransmitters like dopamine and serotonin are crucial for brain function.
- Neomycin is an antibiotic with potential neurological side effects that require investigation.
Purpose of the Study:
- To investigate the impact of neomycin administration on monoamine levels in rat striatal tissue.
- To elucidate the effects of neomycin on dopamine and serotonin pathways in the brain.
Main Methods:
- Rats were administered neomycin (2 mg/kg; i.p.) and observed over 24 hours.
- Striatal tissue homogenates were analyzed using High-Performance Liquid Chromatography (HPLC) with electrochemical detection.
- Levels of dopamine, serotonin, and their metabolites were quantified.
Main Results:
- Neomycin caused a significant increase in striatal dopamine levels (+35%) and a decrease in its metabolite levels (-36%).
- Striatal serotonin levels increased significantly (+130%) within 2 hours post-injection.
- Ratios of DOPAC/DA and 5HIAA/5HT were reduced, indicating altered neurotransmitter metabolism.
Conclusions:
- Neomycin exerts an inhibitory effect on both dopaminergic and serotoninergic systems in the rat striatum.
- Potential mechanisms include altered biosynthesis via enzyme stimulation (tyrosine hydroxylase, tryptophan hydroxylase) or modified enzyme activity (MAO, COMT).
- Calcium channel blockade is also suggested as a possible mechanism for neomycin's neurochemical effects.