Abstract

Ethanol has been established to impair vision but its level of impact on the activity of succinic dehydrogenase (SDH) in visual intracranial relay centers has not been fully analyzed. Effects of chronic administration of ethanol on the activity of succinic dehydrogenase (SDH) was investigated on the lateral geniculate body (LGB) and superior colliculus (SC) in forty adult wistar rats of average weight 200±2.30 g, randomly distributed into four groups (2 treatments × 2 replicate) T1, T2, C1, and C2 (n=10).The animals were fed with standard laboratory mouse chow and provided with water ad libitum. Groups T1 and T2 received 25% ethanol in 2% sucrose solution while groups C1and C2 received distilled water and 2% sucrose solution respectively for six weeks except T2 animals that were allowed an extra 2-weeks ethanol withdrawal period. The animals were sacrificed by cervical dislocation while the regions of LGB and SC were processed for histochemical staining and bioassay of SDH. Shrunken brains were seen in treatment groups with significant brain weight loss (P < 0.01) compared to controls. Histochemical findings showed decreased staining intensity of SDH in both LGB and SC of treatment sections compared to the controls. Biochemical estimation of the enzymatic activity and protein concentration of SDH in LGB and SC showed significantly decreased values (P < 0.05) in treatment groups compared to the control groups. Reduced staining intensity and biochemical quantification findings on SDH suggest that long term intake of ethanol also impairs the process of carbohydrate metabolism via Kreb’s cycle in the neurons of visual relay centers of lateral geniculate body and superior colliculus which may impair visual acuity and sensibilities.

Key words: Ethanol, succinic dehydrogenase, visual relay centers, Kreb’s cycle.