Histological, histochemical and immunohistochemical studies on the paraventricular and supraoptic nuclei of the hypothalamus in the adult new zealand rabbits

الملخص EN

The present investigation aims to give a detailed histomorphological feature of the anterior group of hypothalamus of adult New Zealand rabbits in both sexes.

Specimens were prepared to be examined microscopically by using light and transmission electron microscope.

The obtained results revealed that, the anterior group of the hypothalamus composed of paraventricular (PVN) and supraoptic nuclei (SON).

The paraventricular nucleus was located on either sides of the 3rd ventricle.

It consisted of different-shaped neurons which appeared in the form of clusters and irregular groups intermingled with nerve fibers associated with neuroglia cells and permeated by blood capillaries.

Ultrastructurally, the neurons appeared polyhedral in shape contained large eccentric euchromatic nucleus and electron lucent cytoplasm contained many mitochondria, rER, Golgi apparatus, numerous ribosomes and some secretory granules.

On the other hand, the supraoptic nucleus was located dorsolateral to the optic chiasma and consisted of two portions; thin medial and thick lateral one.

The neurons of the thin medial part appeared pyramidal in shape with vesicular oval eccentric nuclei and lightly stained cytoplasm, while that of the thick lateral one showed irregular groups or rows of oval and pyriform shaped cells contained vesicular rounded eccentric nuclei.

Ultrastructurally, the neurons of the thick lateral part of SON appeared pyriform in shape with spherical eccentric euchromatic nucleus in electron lucent cytoplasm showed intensive network of rER, many mitochondria, Golgi apparatus, numerous free ribosomes and few secretory granules.

The cytoplasmic granules of the PVN and SON neurons gave positive reaction with all nonspecific and specific stains used.

Also, they gave positive immunoreactions when subjected to Anti-CGA and Anti-NSE antibodies.

There were no microscopic structural differences correlated to neither sex nor age of studied animals.