Embryonic exposure to thimerosal, an organomercury compound, causes abnormal early development of serotonergic neurons

Neurosci Lett. 2011 Nov 14;505(2):61-4. doi: 10.1016/j.neulet.2011.05.053. Epub 2011 Jun 6.


Even though neuronal toxicity due to organomercury compounds is well known, thimerosal, an organomercury compound, is widely used in pediatric vaccine preservation. In the present study, we examined whether embryonic exposure to thimerosal affects early development of serotonergic neurons. Thimerosal (1mg Hg/kg) was intramuscularly administered to pregnant rats on gestational day 9 (susceptible time window for development of fetal serotonergic system), and fetal serotonergic neurons were assessed at embryonic day 15 using anti-serotonin antibodies. A dramatic increase in the number of serotonergic neurons localized to the lateral portion of the caudal raphe was observed in thimerosal group (1.9-fold increase, p<0.01 compared to control). These results indicate that embryonic exposure to thimerosal affects early development of serotonergic neurons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / drug effects
  • Cell Differentiation / physiology*
  • Disease Models, Animal
  • Female
  • Nervous System Malformations / chemically induced*
  • Nervous System Malformations / embryology
  • Nervous System Malformations / pathology
  • Pregnancy
  • Prenatal Exposure Delayed Effects / chemically induced*
  • Prenatal Exposure Delayed Effects / pathology
  • Preservatives, Pharmaceutical / toxicity
  • Raphe Nuclei / abnormalities*
  • Raphe Nuclei / drug effects*
  • Raphe Nuclei / embryology
  • Rats
  • Rats, Wistar
  • Serotonergic Neurons / drug effects*
  • Serotonergic Neurons / pathology*
  • Thimerosal / toxicity*


  • Preservatives, Pharmaceutical
  • Thimerosal