Light and electron microscopic autoradiographic investigation of the septo-dentate pathway in rat brain

• Main Author: Rose, Ann Marie
• Language: English
• Published: 2010
• Subjects: Synapses; Hippocampus (Brain); Hippocampus
• Online Access: http://hdl.handle.net/2429/19827

This study was undertaken to resolve the conflict between two existing studies regarding the layer in the dentate gyrus where the septal fibers terminate. This was accomplished by injecting radioact ively labelled amino acids into the medial septum where they were incorporated into protein by the cell bodies and transported to the nerve terminals. Autoradiographic grain counts showed labelling was moderately heavy in the subgranular zone of the dentate gyrus, whereas labelling was scant in the molecular layer. These findings support the work of Raisman et al., (1965), but indicate the degeneration seen by Mosko, et al., (1973) in the molecular layer may have been artefactual. The ultrastructure of the septal terminals in the subgranular zone of the dentate gyrus was described. These terminals formed asymmetrical synapses onto dendrites and spines, and contained clear round vesicles. They resembled cholinergic nerve terminals described in other regions of the brain. These findings agree with accumulating evidence that the septo-dentate pathway is cholinergic. === Medicine, Faculty of === Graduate