Larvae Isolation Stress (ms) And Dexamethasone (dex), The Role Of Development Of The Mandarin Vole Social Behavior

Stressful experiences during postnatal development can cause long-lasting changes in neuroendocrine systems as well as lasting changes in behavior.The maternal separation paradigm represents a promising animal model to reveal underlying mechanisms of behavioral dysfunctions associated with early life stress.In rodents,3-h daily maternal separation during the first 2 weeks of life has repeatedly been shown to increase anxiety and stress responsiveness in adulthood.Several animal models had been used to describe the long-term effects of early life stress on the physical and behavior.In the present study,we studied the development of changes caused by maternal separation in neuroendocrine systems as well as lasting changes in behavior.Selecting monogamous mandarin voles(Microtus mandarinus) as experimental animal,using i.p injection,immunohistochemistry and behavior observation methods,we tested the preference of mandarin voles for mate or strange heterosexual vole,and compared the behavior in the test of social interaction.Then we used FOS immunohistochemical method to identify the neuron activity.Also,we used AR immunohistochemical method to identify the AR expression.Our results were as follow:1.The present study we individed the monogamous mandarin voles(Microtus mandarinus) into 3 groups.MS,DEX and UNTR.We test the social behavior in the adulthood when the animals grew up to 60-90 days.There were no significant preference of UNTR female and male mandarin voles to mate heterosexual vole,P＞0.05;Animals in the MS shew significant preference of female and male mandarin voles to the mate voles.Total duration and total number of Investigating behavior to strange heterosexual vole decreased in the female of MS.For male in MS,total duration of investigating behavior,latency of amicable behavior to mate heterosexual vole had been decreased;but the duration of the mate's nonsocial behavior had been increased.To the strange heterosexual vole,the latency of aggression and latency of defensive behaviors decreased.There were significant preference of MS female and male mandarin voles to mate heterosexual vole.2.There were significant preference of DEX female mandarin voles to mate heterosexual vole. But the male were different.In the experiment of mate choose,for the female,total duration of aggressive behavior had been increased and latency of aggressive behavior decreased to the strange heterosexual.For the male,to the mate heterosexual,total duration of defensive behaviors decreased and latency of defensive behaviors increased;the total duration and total number of investigating behavior decreased;the total number of amicable behavior increased and the latency decreased.For the male,to the stange heterosexual,the latency of aggressive behavior decreased.3.Compared to MS group,the female of the DEX group spent less time on investigating behavior to strange heterosexual.Interaction between the male and the mate heterosexual,the total duration of nonsocial behavior decreased.The total number of defensive behaviors decreased and the latency increased.In a word,DEX treatment weaken the preference of mandarin voles for mate.4.Compared to UNTR group,in the social interaction experiment,the duration and total number of aggressive behavior decreased,total duration and total number of the self-modification increased for the female in MS group,for the male,the total duration of investigating behavior increased.The expression of FOS and AR were consistent with the behaviors.5.Compared to UNTR group,In the social interaction experiment,the total duration of aggressive behavior decreased of the female in DEX group,.The expression of FOS and AR were consistent with the behaviors.The results suggest that:stressful experiences during postnatal development can cause long-lasting changes in neuroendocrine systems as well as lasting changes in behavior.There were complex neuro relation between central neuro system and AR system.The two system regulate the social behavior together.The further research of the function of MS uctional mechanism would make sense in social problem,such as autism and tendency of violence.