Effect Of Chronic Stress On Memory And Emotion In Olfactory Deficient Mice And Effect Of Olfactory Deficient On LTD In Mice Hippocampal CA1

Smell is one of the animal’s most important sense. The olfactory system is a very complicated system, its projection relates to a number of important areas in the brain such as the amygdala, hippocampus, prefrontal and orbitofrontal cortex which is related to emotion, learning and memory. Clinical studies found that damage of olfactory function is often accompanied with dementia, Parkinson and other degenerative diseases. On the other hand, some patients with mental disorders (such as depression, anxiety) not only showed abnormal activity in hippocampus and amygdala areas, but also showed olfactory disfunction. However, it is not clear the causality between olfactory injury and depression. Previous researchers found that stress (especially chronic stress) were closely related to mental diseases. Anosmia is a kind of stress, and stress, the olfactory projections overlap with stress and depression related areas in the brain. But at present we know little about the effect of chronic stress on anomsia related brain disfunction.The olfactory-deficient mice was induced by injection the solution of zinc sulfate into nasal to destroy olfactory mucosa cells. Chronic stress was applied to anosmia mice. Then, we examined the behavior, smell, memory, emotion and neural plasticity in olfactory deficient mice. We found that olfaction were damaged by the solution of zinc sulfate, and their spatial memory ability were impaired by anosmia. Chronic stress can promote olfaction recovery, and improve spatial memory in anosmia mice. But chronic stress can cause depression like behavior in olfactory deficient mice. Furthermore, the amplitude of early phase LTD was significant reduced in Olfactory deficient mice. Our study suggested that chronic stress may exert versatile action on brain function in anosmia mice to enhance learning and exaggerate depressive behavior.