The Research Of Neural Fiber Links Between The Ventromedial Nucleus Of Hypothalamus And Hippocampus In Rats

Objective: To reveal the afferent and efferent nerve fiber links between the ventromedial nucleus of hypothalamus(VMH)and hippocampus in rats,providing the morphological basis for internal activities such as feeding and energy metabolism of nerve regulation mechanism research.Methods: Referenced to the stereotaxicatlas of rats,with the help of the brain stereotaxic instrument,retrograde tracer Evans blue(EB)was injected into the left side of VMH(group A,18)or hippocampal CA2 area(group B,18)of SD rats.Three days later,4% paraformaldehyde cardiac perfusion,frozen sliced and reserved under the fluorescence microscope.Group C(VMH control group)and group D(hippocampus control group)were injected the same dose of deionized water as group A and group B.Results: The results of this experiment are as follows:Group A,including 18 rats,2 of them died due to bleeding or intracranial infection after 4 days feeding.The injecting site of 12 rats have been proved to be accurate by observing the inverted fluorescence microscope,and bilateral hippocampal CA2,CA3 region labeled with fluorescence clearly.There is a statistically significant difference among different EB doses(P<0.05)and average fluorescent labeling cells on the right side compared to the left side of the hippocampus(P<0.05).Group B,including 18 rats.The injecting site of 16 rats have been proved to be accurate by observing the inverted fluorescence microscope after 4 days feeding.Fluorescence labeling cells were not observed in VMH no matter how doses EB injected.Group C,including 18 rats.The injecting site of 11 rats have been proved to be accurate by observing the inverted fluorescence microscope after 4 days feeding.Fluorescence labeling cells were not observed in both sides of the hippocampus.Group D,including 18 rats.The injecting site of 15 rats have been proved to be accurate by observing the inverted fluorescence microscope after 4 days feeding.Fluorescence labeling cells were not observed in VMH.Conclusion: The conclusions of this experiment are as follows:1 There are nerve fibers projection from Hippocampus to VMH and not yet found nerve fibers projection from VMH to Hippocampus,meaning the fiber connection may be one-way projection.2 VMH could accept the projection fibers from bilateral hippocampal CA2,CA3 area,and the ipsilateral projection is stronger than contralateral projection.