Objective: Study of normal histological feature of brain in Rutlus frissi kutum.
Design: Descriptive study.
Animals: Five adult and normal fish.
Procedure: A total number of five fish from Caspian sea fishing regions were subjected to this study. Tissue specimens were taken from mesencephal and cerebellum. After fixation in 10% fromalin for 24h, they were transferred into the tissue processor, Paraffin blocks were made and thin sections of five micron were cut, The sections were subjected to staining by hematoxylin and eosin and were studied under the light microscope and photomicrographs were taken.
Results: The different parts of the brain were, telencephal, diencephal, mesencephal, cerebellum and myclcnccphal. The mesencephal and cerebellum were composed of both white and gray matter. White matter contained myelinated and unmyclinated fibers and microglical cells.
Conclusion: This species in the Caspian sea like the other vertebrates, possess a density of nervous tissue as brain in the rostral part of the body. Considering the extension of brain this species can be compaired with higher vertebrates. In this fish the mesencephal which is responsible for vision has highly developed. For this, they have sharp-sighted eyes and seem to be good chasers. Generally the vision power of fishes are diffirent and more dependent with their habitat. Cerebellum occupies most of the hindbrain and It’s weight is different in each fish and histologically the arrangement and shape of the constituting cells are similar to those of other fishes and mammals. J. Fac. Vet. Med. Univ. Tehran. 57, 2: 15-18, 2002.