Circadian profile of salivary melatonin secretion and its concentration after epileptic seizure in patients with drug-resistant epilepsy – Preliminary report

BackgroundThe results of a few previous studies assessing melatonin concentration in epileptic patient are ambiguous. This study aimed at: (1) comparing the circadian profile of salivary melatonin excretion in epileptic patients with that in healthy subjects and with circadian frequency profile of seizures and (2) assessing the effect of epileptic seizure upon salivary melatonin concentration.MethodsThe study included thirty patients suffering from drug-resistant epilepsy aged from 22 to 45 years (mean age 37.17, SD ± 10.25). All subjects had their saliva taken in order to determine melatonin concentration and its circadian excretion profile performed every 4 h. Additionally, saliva samples were collected in order to assess concentration of melatonin directly after epileptic seizure and 2 h later.ResultsThe circadian profile of melatonin secretion in epileptic patients did not differ significantly from a profile in healthy subjects. Epileptic women showed statistically higher average salivary melatonin concentration at 2 a.m., 6 a.m. and 10 a.m., compared to epileptic men; this may be related to lower age average of women as well as to their different hormonal profile.ConclusionThe significantly higher salivary melatonin concentration at 6 a.m. in patients with diurnal seizures (occurring mainly in the morning) may suggest proconvulsive effect of this hormone. Epileptic seizure did not lead to significantly elevated salivary melatonin concentration. Epileptogenic effect of melatonin might be corroborated by significantly elevated salivary melatonin levels directly after nocturnal tonic–clonic seizure which affected patients with highest concentration of this hormone at 2 a.m. These observations would need confirmation based on studies of larger groups of epileptic patients.