Abstract

Activities of glucose-6-phosphate dehydrogenase (G-6-PDH) for the pentose phosphate pathway and lactate dehydrogenase (LDH) for the glycolytic pathway were compared in the rat (Rattus norvegicus), bat (Eidolon helvum) and pangolin (Manis tricuspis) visual relay centers to observe possible modifications that enable these mammals to cope with their habitation. Ten species each of both sexes were used for this study.  After being sacrificed by cervical dislocation, their skulls were opened using bone forceps to expose the brains. The superior colliculi (SC) and lateral geniculate bodies (LGB) were excised from each brain, and were homogenized using Polter-Elvehjem homogenizer and assayed spectrophotometrically for the activities of G-6-PDH and LDH. It was observed that the histochemical activities of the enzymes showed significant differences (p < 0.05) of both SC and LGB of the three mammals as revealed in the quantitative histochemical localization of these two enzymes of carbohydrate metabolism. The result indicated that enzymes of carbohydrate metabolism play a vital role in the visual functions of these mammals.

Key words: Superior colliculus, lateral geniculate body, glucose-6-phosphate dehydrogenase, lactate dehydrogenase.