Histological, histochemical, and immunohistochemical studies of hippocampus in male New Zealand rabbits

Abstract

The present study aims to give detailed histomorphological features of the hippocampus of adult male New Zealand rabbits. Both histological and histochemical specimens were prepared to be examined microscopically by using a light microscope. The hippocampus appeared as C‐shaped hippocampal proper, dentate gyrus, and subiculum. The hippocampal proper subdivided along its length according to the density and size of its major constituent pyramidal cells into four distinct regions named Cornu Ammonis (CA1, CA2, CA3, and CA4). With the histochemical preparations, each of these regions consisted of five layers, stratum alveolus, stratum oriens, stratum pyramidale, stratum radiatum, and stratum lacunosum‐moleculare. The stratum pyramidale constituted the middle dark zone and contained the principal excitatory neurons and a few interneurons. Histochemically, the pyramidal neurons along all regions of the CA reacted positively to Grimelius silver impregnation, lead hematoxylin, Gomori's aldehyde fuchsin, aldehyde thionine, Gomori's chrome alum hematoxylin, and performic acid alcian blue stains. Immunohistochemically, the pyramidal neurons reacted positively to anti‐NSE antibodies. The dentate gyrus was formed of three distinct layers. The subiculum was formed of proper subiculum, presubiculum, and parasubiculum.

The Anatomy of the Hippocampus

“…Cornu ammonis of the hippocampus can be subdivided into four regions (Figure 2, 3): CA1, CA2, CA3, and CA4 (13)(14)(15)(16)(17). The CA1 is the largest region and is delimited laterally by the presubiculum and medially by CA2.…”