Difference between a normal control rat and the vacuolization of pyramidal neurons in the CA3 region of a rat treated with domoic acid

(Left) CA3 region of the hippocampus of a control rat showing a cluster of pyramidal cells with good preservation and integrity of cell membranes and organelles. The nucleus (N) and nucleolus (ncl) are easily identified. A well-preserved electrodense dendritic spine is shown (arrow). Scale Bar = x2.5μm. (Right) CA3 region of the hippocampus of a rat treated by gavage domoic acid for 64 days. Image shows a pyramidal cell with easily identifiable nucleus (N), the cytoplasm and surrounding neuropil with numerous vacuoles (V) of various sizes giving a "Swiss cheese" effect. The neuropil refers to intricate interwoven cell processes including glial processes, synaptic terminals, axons, and dendrites that are interspersed among the nerve cells in the gray matter of the CNS. Scale Bar = x2.5μm. (Source: Pulido 2008. Creative Commons Attribution license. http://creativecommons.org/licenses/by/3.0.)