Changes of the Cholinergic Innervation to the Hippocampus after Entorhinal Cortex Lesion in Rat / 대한해부학회지

The hippocampus is known as involved in learning and memory functions and the entorhinal cortex plays a crucial role as a gateway connecting the several areas and hippocampal formation. Entorhinal cortex lesions have been employed in numerous studies as the Alzheimer's disease model. The purpose of this study were to identify the CNS hip-pocampal and cholinergic pathway and to investigate the morphological changes of the hippocampal cholinergic inner-vations by using the Pseudorabies virus injection into the hippocampus after entorhinal cortex lesions. The pseudorabies virus and double labelled neurons (ChAT and PRV) were distributed at several different nuclei including agranular insular cortex, bed nucleus of stria terminalis, central amygdala, globus pallidus, lateral segment, lateral hypothalamic area, laterodorsal tegmental nucleus, medial septal nucleus, mesencephalic reticular nucleus, periaqueductal gray matter and substantia innominata The morphological changes were observed in the hippocampal cholinergic innervation after entorhinal cortex lesions. These data suggested that the hippocampal cholinergic innervation showed morphological changes throughout the whole brain areas after entorhinal cortex lesion.

CNS cholinergic innervation to the hippocampus in the rat using pseudorabies virus as a neurotracer

The hippocampus is a central area of the memory-related neural system. Combined immunohistochemistry against choline acetyl transferase and retrograde transneuronal labelling of the pseudorabies virus were used to identify cholinergic neurons in the central nervous system projecting to the hippocampal formation of the rat. Five to ten microL of Bartha strain of pseudorabies virus were injected into the dentate gyrus, CA1 and CA3 of the hippocampus of 20 Sprague Dawley rats using stereotaxic instrument. Forty eight to 96 hr after the injection, the brains were removed and the tissue sections were processed for double immunofluorescence procedure using polyclonal antibodies against pseudorabies virus or choline acetyl transferase. The double labelled neurons were distributed at several different nuclei and the labelling patterns of three different areas of the hippocampus were similar. These data suggests that the cholinergic innervation to the hippocampus were distributed in a transsynaptic manner throughout the whole brain area.

Central Vagal Involvement in Ovarian Innervation of the Rat / 체질인류학회지

The mammalian ovary has been known as receiving its innervation by sympathetic and sensory neurons of the peripheral nervous system from the brain. Recently, there were several functional reports that the vagus nerves were also regulating the ovarian function, but the vagus nerve had not been identified by clear morphological evidence. A viral transneuronal tracing technique has been used to demonstrate the morphological evidence for the central vagal involvement in ovarian innervation in brain areas. Bartha strain of pseudorabies virus injection was made into the ovary of Sprague Dawley rats. In experimental group, the vagus nerve of the same injection side was removed right after ovarian injection. At five days after initial injection, all the rats were sacrificed and brains were processed for immunohistochemistry. Several central nuclei including hypothalamic paraventricular nucleus showed strong bilateral positive labelings after unilateral injection in control rats, but the positive labelings were disappeared or decreased in several hypothalamic nuclei and nuclei of the vagus nerve. In conclusion, these results provide the morphological evidence that vagus nerve has neural connection to ovary and by which the central nervous system may maintains the state of ovulation and reproduction as a possible parasympathetic routes in mammals.