Interactions between neomycin and cerebral dopaminergic and serotoninergic transmission in rats.
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.
el Ayadi
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Department of Biology, Abdelmalek Essaâdi University, Morocco.
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D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000633:toxicity; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology* / Q000633:toxicity; D015220:Calcium Channels / Q000187:drug effects*; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000502:physiology*; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism; D009355:Neomycin / Q000494:pharmacology* / Q000633:toxicity; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000502:physiology*; D013268:Stimulation, Chemical; D014365:Tryptophan Hydroxylase / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D000900:Anti-Bacterial Agents; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009419:Nerve Tissue Proteins; D012701:Serotonin; D014446:Tyrosine 3-Monooxygenase; D014365:Tryptophan Hydroxylase; D008995:Monoamine Oxidase; D002394:Catechol O-Methyltransferase; D009355:Neomycin; D002118:Calcium; D004298:Dopamine