Isoflurane increases, but sevoflurane decreases blood concentrations of melatonin in women

Abstract  The blood concentrations of melatonin are elevated by stress-induced sympathetic nerve excitation and are affected by some anesthetics. Isoflurane has an effect to increase sympathetic nerve activity when compared with sevoflurane. This study was performed to investigate the effects of these two anesthetics on the blood concentrations of melatonin. Female patients were anesthetized with either isoflurane or sevoflurane. We obtained blood samples before and 5min after 5% isoflurane (ISO group) or 7% sevoflurane (SEV group) anesthesia. The blood melatonin concentrations during anesthesia in the ISO group increased significantly, from 65 ± 60 to 170 ± 90pg·ml–l; mean ± SD (P < 0.05), whereas those in the SEV group decreased, from 60 ± 50 to 30 ± 30pg·ml–l (P < 0.05). In conclusion, isoflurane increases, but sevoflurane decreases blood melatonin concentrations.