Morphometric and Stereological Studies of the Pons and Medulla Oblongata of the African Striped Ground Squirrel (Xerus erythropus)

Abstract

The study was undertaken to investigate the structure and functional relationships of the pons and Medulla Oblongata of African Striped Ground Squirrel (Xerus erythropus). Twenty (20) adult African striped ground squirrels were used for this study (10 males and 10 females). The ground squirrels were obtained from the surrounding villages of Zaria Local Government, Kaduna state Nigeria. Each Squirrel was euthanized using ketamine hydrochloride at 80mg/kg bw followed by gentle perfusion with neutral formal saline. A pair of scissors, chisel and scalpel blade were used to gently extract the brain (craniotomy). The extracted brain was fixed in Bouin’s fluid for 24 hours and processed histologically. Morphometrically, the absolute brain weight was higher in male than female while the brain length was higher in female. The absolute weight of medulla oblongata was significantly higher in male than female (p<0.05). Stereologically, the neuronal volume of medulla oblongata was higher in female squirrel than in male while male squirrel has higher neuronal number of pons and medulla oblongata. In conclusion, the higher brain morphometry in male squirrels may be suggestive of a higher locomotive activity and a good climbing ability than the female counterpart.