Expression Of NOS And ER Double-labeled Neurons In Paraventricular Nucleus And Supraoptic Nucleus Of The Postnatal Rat

Objective:(1)Exploring the changes of quantity and expression of NOS positive neurons and ER-IR neurons in the hypothalamus of rats is to show the inherent relationship between nitric oxide(NO)and estrogen.(2)Defining the changes of morphology and coexistence of NOS positive neurons and ER-IR neurons in the hypothalamus of the born rats is to further inquire the action mechanism of nitric oxide(NO)and estrogen.Methods:According to the survival time at the day 10,20,30,60,90 after being born,40 SD rats were divided into 5 groups,n=8 for each group.Using NADPH-d histochemical technique combined with immunohistochemical method,Coronal slices of 40 SD-rats'hypothalamus were collected to observe the diameter and number of NOS positive neurons,ER-IR neurons and NOS/ER double-labeled neurons in paraventricular nucleus(PVN)and supraoptic nucleus (SON)of the rats'hypothalamus and the proportion of double-labeled neurons in each age group.Results:(1)The more concentrated ER-IR neurons were seen in the supraoptic nucleus of hypothalamus at the tenth day after being born.With the age increasing,the expression level of ER was improved gradually and reached the adult level till the 90th day after being born.The quantity of expression of ER in PVN was higher during the early stage after being born(before the tenth day),decreased the 20th day after being born,the least at the 30th day after being born,and increased gradually to reach the adult level from the 30th day to the 90th day after being born.In a word,The quantity of expression of ER in hypothalamus appeared the trend increasing firstly and then decreasing.(2)10 days after being born located in supraoptic nucleus (SON)of the hypothalamus of the rats,NOS/ER double-labeled neurons occupied minority, which cell plasma is blue,cell nucleus is buffy and bigger,and neurite is shorter.With the postnatal development,the number of double-labeled neurons in supraoptic nucleus(SON) increased significantly,neurite lengthening and interweaving.In 10 days after being born group, NOS/ER double-labeled neurons were distributed more concentratedly in the Paraventricular hypothalamic nucleus ventral part(PaV)and were scattered in the parvocellular division,PaP.The double-labeled neurons was elliptic,neurite in the PaV With the increase of age,the number of double-labeled neurons grew in number,neurite lengthening.In 90 days after being born group, the double-labeled neurons were distributed more concentratedly in the PaY,their neurites interweaving with neighbourhood ones.It is not easy to differentiate.They were elliptic or shuttle-shaped,occupied beyond 80～90%.Conclusion:(1)There are coexistence of NOS and ER in the hypothalamic supraoptic nucleus and paraventricular nucleus of rats in each stage after being born.(2)During the course of growth and development of rats,the level of estrogen has positive regulation to expression of NOS positive neurons in the hypothalamic supraoptic nucleus and paraventricular nucleus.