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[Effect of S-adenosyl-L-methionine on cerebral monoamine turnover after hypoxia in rats]
Abstract:
The effects of S-Adenosyl-L-methionine (SAMe) on cerebral monoamine turnover at 60 min of reoxygenation after hypoxia (PaO2, 31-35 mmHg) for 15 min were studied in 44 rats anesthetized with nitrous oxide. The accumulations of monoamine metabolites: 3-methoxy 4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were determined after probenecid. The accumulations of noradrenaline (NA) and dopamine (DA) were also determined after pargyline. In the non-treated group, there was an impairment of degradation of NA to MHPG and of DA to DOPAC or HVA in the control group (no hypoxia). These changes were accompanied by higher levels of NA and DA in the cerebral cortex, hypothalamus and striatum than those of the control group. In the group treated with 100 mg/kg SAMe plus 38 mg/kg mannitol 3 min after the start of reoxygenation, there were no significant changes in these metabolites and amines. Mannitol alone did not cause significant changes. There were no changes in serotonin and 5-HIAA in any of the groups studied. The effects of SAMe were studied in an additional 16 awake rats. MHPG in all regions measured after probenecid in the rats treated with SAMe was higher than that without SAMe. It appears that SAMe ameliorates perturbation of cerebral catecholamine turnover produced by reoxygenation after hypoxia.
Insights
S-Adenosyl-L-methionine (SAMe) appears to protect against changes in cerebral catecholamine turnover caused by reoxygenation after hypoxia. This suggests SAMe may be beneficial in mitigating neurological damage from oxygen deprivation.
Area of Science:
- Neuroscience
- Biochemistry
- Pharmacology
Context:
- Hypoxia followed by reoxygenation can disrupt normal brain function.
- Cerebral monoamine turnover is crucial for neurological processes.
- Investigating neuroprotective agents is vital for understanding brain injury.
Purpose:
- To investigate the effects of S-Adenosyl-L-methionine (SAMe) on cerebral monoamine turnover during reoxygenation after hypoxia.
- To determine if SAMe can prevent or reduce biochemical changes associated with hypoxic-ischemic brain injury.
- To assess the impact of SAMe on catecholamine and metabolite levels in rat brain regions.
Summary:
- Studies in rats showed that hypoxia followed by reoxygenation impaired the degradation of noradrenaline (NA) and dopamine (DA).
- Treatment with SAMe (100 mg/kg) significantly prevented these alterations in monoamine metabolites (MHPG, DOPAC, HVA) and amine levels.
- No significant changes were observed in serotonin or its metabolite (5-HIAA), and mannitol alone had no effect.
Impact:
- SAMe demonstrates potential as a therapeutic agent to ameliorate disruptions in cerebral catecholamine turnover caused by reoxygenation after hypoxia.
- Findings suggest SAMe may offer neuroprotection against hypoxic-ischemic insults by stabilizing monoamine systems.
- Further research into SAMe's mechanisms and clinical efficacy in neurological conditions is warranted.