Investigation of the effect of desflurane administeration during day and night period on melatonin levels in rats

Objective: The aim of this study is to investigate the effects of night-day application of desflurane on the melatonin level in rats. Materials and Methods: Twenty-four rats,15 days old,were included in the study and randomized into four groups.Rats were administered 5,7% desflurane at 6L/min flow rate in 100% oxygen from 19:00 to 01:00 (night group), and from 07:00 to 13:00 (day group) during the spring.Contols groups were administered oxygen at 6L/min flow rate during the same time periods.At the end of six-hour period,blood samples of the rats were obtained and then the rats were sacrificed. Blood specimens were centrifuged and melatonin concentrations were measured in plasma by radioimmuno assay. Results: In the comparison of Group night desflurane (GN-D) and Group night control (GN-C) for melatonin levels, no significant difference was detected (p=0,652).In the comparison of Group day desflurane (GD-D) and Group day control (GD-C)for melatonin levels,GD-D displayed significantyl higher levels of melatonin (p=0,011). GN-C showed significantyl higher plasma melatonin concentrations compared to GD-C (p=0,007). Conclusion: We determined that six--hour administration of 5,7% desflurane to 15 days old rats during the day increased plasma melatonin concentration, however the same desflurane administration during the night did not cause any change in plasma melatonin concentration. Key words: Desflurane, rat, plasma melatonin