Melatonin Corrects Depressive-like Behaviour and Anxiety in Male and Female Offspring Rats in a Model of Prenatal Melatonin Deficit

Abstract

Melatonin deficiency caused by a prolonged light regime leads to a disturbance in the circadian rhythmicity of a number of physiological and biochemical parameters, including disruption of the synchronizing role of the hormone on endocrine and metabolic functions in the body. The aim of the present study was to explore the sex-dependent consequences of prenatal exposure to constant light (CL) on behavioural responses of rat adult offspring. In addition, the effect of melatonin supplementation on pregnant rats exposed to CL was evaluated on emotional disturbance due to melatonin deficiency. Chronic exposure to CL during pregnancy induced impaired emotional responses in male and female adult offspring, including decreased visits to aversive central zone in the open field test and elevated plus maze test and reduced consumption of sweet solutions. The elevated anxiety and anhedonia was corrected in a generation of prenatal melatonin-deficient rats of the two sexes. Our results suggest that prenatal rat exposure to CL provokes long-term behavioural impairments in male and female adult offspring. The beneficial role of melatonin supplementation on these disturbed responses suggests that our prenatal model induces melatonin deficiency that causes sustainable changes in offspring. Further data are needed to ascertain the mechanism underlying the prenatal-induced deleterious effect of melatonin deficiency and possible therapeutic options.