Effect of maternal stress on circadian rhythm and metabolism

Abstract

It is well established that maternal stress causes defective functions in several important brain regions such as hypothalamus, hippocampus and amygdala. However, the effect of maternal stress on the suprachiasmatic nucleus (SCN) which acts as a central pacemaker driving circadian rhythm remains largely unknown. In the present study, I focused on the question whether stress in pregnant mice could influence the circadian clockwork in the SCN of their offspring and its physiological relevance. SCN slices from 1 week-old transgenic mice maintained rhythmic PER1::LUC expression for more than a week, and maternal stress caused shortened periodicity and reduced amplitude, and even loss of rhythm in some cases. However, in SCN slices from 5 week-old mice, altered period and arrhythmicity were recovered as similar to those of adult mice while the amplitude of PER1::LUC was still lower than the control group. In addition, mRNA profiles of several molecular clock genes in liver of prenatally stressed adult mice were affected. In accordance with the liver clock, rhythmic profiles of metabolic genes involved in glucose metabolism were altered in maternally stressed mice. However, although liver glycogen contents were slightly decreased, plasma glucose levels were not changed, suggesting that maternal stress cannot disrupt glucose homeostasis in normal feeding condition. Taken together, these findings suggest that maternally stressed mice can adjust to their environment after birth, likely for overcoming the effect of prenatal stress on circadian timing system