[Effect of S-adenosyl-L-methionine on cerebral monoamine turnover after hypoxia in rats].

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.