The Center for Alternatives to Animal Testing is an academic center affiliated with the Division of Toxicological Sciences in the Department of Environmental Health Sciences of the Johns Hopkins University Bloomberg School of Public Health.

 

Johns Hopkins School of Public Health

Research Grants 2004-2005

Organotypic Culture of Cerebellar Slice for Studies of Developmental Neurotoxicity of Methylmercury

William D. Atchison, Ph.D.
Michigan State University, East Lansing, Michigan

Methylmercury (MeHg) is extremely toxic and among the most common forms of mercury found in the environment. MeHg causes prominent neurotoxicicity. The developing brain is especially sensitive to MeHg. Our goal is to understand the mechanisms responsible for this selective vulnerability of certain cells in the brain to MeHg. During development, neurons migrate from one region of the brain to another. This process, can be studied using cultures of brain slices of neonatal rat. Migration of these neurons involves the complex interactions between chemical messengers known as neurotransmitters which either excite, or inhibit electrical activity in the neurons. We propose to develop this system, in our lab for studies of developmental neurotoxicity with MeHg. This preparation can be used for studies of acute and semichronic exposure to MeHg, thus reducing the need for semichronic injections of neonatal animals with MeHg. Furthermore, more than one preparation can be made from a single rat brain, animal, again reducing the overall number of animals needed for a series of studies. Because this preparation maintains the normal intact and developing synaptic connections, it offers a greater advantage over cell culture systems in which the normal connections between neurons (known as circuits) are lost. Movement of cerebellar neurons (in particular, a group called the "granule cells") and concurrent measures of changes in calcium within the cell will be studied using confocal laser scanning microscopic measures in response to acute and sernichronic exposure to MeHg. These studies will be an important contribution to the understanding of developmental neurotoxicity with MeHg.