Effects of prenatal exposure to lithium on indoleamines in maturing mouse brain

Levels of the intermediates 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) and activities of the enzymes 5-hydroxytryptophan decarboxylase (5-HTPD) and monoamine oxidase (MAO) were measured in 4 different brain regions of maturing mice exposed to LiCl during prenatal and postnatal development. 5-HT and 5-HIAA levels were reduced significantly in all brain regions of 1 day old mice. 5-HIAA was also reduced in hemispheres of 1 week olds. There were some marginally significant elevations and reductions in 5-HTPD and MAO activity at various ages. It is suggested that lithium is reducing 5-HT synthesis and perhaps storage also but that neonates recover quite rapidly from the prenatal exposure.