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Objective To study the expression levels of interlukin-18(IL-18) in the CA1 region of the hippocampus and habenular of the rats with chronic stress. Methods Male Wistar rats (n = 30) weighting about 185～255g were divided into test group (T, n = 15) and control group (C, n = 15) randomly. The rats in group T were exposed to various types of stresses every day for consecutive 21 days. The rats in group C did not receive any stress during 21 days. Weighting and open-field tests were carried out on each rat before the test and on the 22nd day. On the 22nd day, brains were removed and cut coronally. Immunohistochemistry method was used to measure the expression levels of IL-18. Results After 21 -day stress, the body weight, erection time, rearing times, horizontal crossing numbers,modifying times and defecation in group T((297.33 ±25.83)g,(5.14 ±2.02)s,(19.00 ± 9.01), (9.47 ±3.64),(3. 93 ± 1. 87)and(4. 93 ± 1. 94)) were significantly different from those of group C((322.00 ±30.34)g,(1.97 ±0.93)s,(39.80 ±18.58),(14.80 ±5.88),(7.27 ±2.87)and(1.93 ±1.16)) (P < 0.01, P < 0.05). The average optical density values of IL-18 positive cells in CA1 region and habenular in group T ((0.3923 ±0.0084 and 0.4577 ±0.0234)) were higher than that in group C ((0. 3165 ±0.0063 and 0. 3400 ±0.0097)) (P<0.01). Conclusion The expression levels of IL-18 of the hippocampus glial cells and of the habenular neurons in the rats is increase after the chronic stress.
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Objective To observe the effects of estrogen on the behavior and the norepinephrine level in the habenular nucleus of depressive rats,and explore the mechanism of estrogen involved in the process of antidepression.Methods Thirty rats were chosen from forty male Wistar rats,which had the similar scores in open field test.The depression models of rats were established by chronic mild stress.Open field test and forced swimming test were performed to detect the behavioral changes between rats with ovary excision(OVX) and with estradiol-treated ovary excision(OV/ER).High performance liquid chromatography(HPLC) was used to observe the changes of norepinephrine level in habenular nucleus.Results After 21-day chronic mild stress,the open field test showed that the vertical motion and cross motion in OV/ER group were increased(P
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Objective:In this experiment we used pain-related neurons of Hb unit discharges recording asa standard to observe the effects of prostaglandin E2 (i. p. ) on Hb unit discharges. Methods :The methodsof unit discharges recording and radiant heat induced tail flick responce were used. Results :The dischargesof pain-excited neurons increased after the addition of PGE2 (i. p. ). The discharges of pain-inhibited neu-rons dec reased after the addition of PGE2(i. p. );PGE2(i. p. ) caused the pain threshold to drop after sym-pathetic nerves were destroyed by 6-OHDA. There were no changes of the pain threshold in undestroyedgroup (P＞0.05). The percentage changes of Hb neurons dropped compared with that of undestroyedgroup (P＜0. 05). Conclusion: The PGE2 could change the discharges of pain-related neurons in Hb, inwhich the sympathetic system might participate in the process.
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Objective:To observe the change of BDNF level expression in experimental in hippocampal and habenular nucles in experimental depression rats.Methods:The depression model of rats was established by chronic unpredictable mild stress. Openfield test was performed to detect the behavior of rats. Immunohistochemistry was used to observe the changes of BDNF level.Results:Compared to the control group,the number of depressed animals was much less than that of normal animals.Conclusion:The level of BDNF decrease significantly in experimental depressive model of rats.
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WGA-HRP was iontophoretically delivered into the habenular nuclei in 40 rats to observe the distribution of the retrograde labeled cells; and into the entopeduncular nucleus(EPN), lateral preoptic area(LPO), medial preoptic area(MPO), nucleus septalis fimbriatis(SF), nucleus triangularis septi(TS), nucleus tractus diagonalis (Broca)(DBN)and lateral hypothalamic area(LHA) in 12 rats to observe the distribution of the orthograde labeled fibers in the habenular nuclei. It was found that the afferents of various parts of the habenular nuclei were different.The lateral habenular nucleus mainly recieves the afferents from the EPN, LPO and LHA, and the medial habenular nucleus from the SF, TS and LHA. Furthermore, the lateral habenular nucleus can be divided into medial and lateral parts, the medial habenular nucleus can be divided into medial and lateral parts as well, their afferent connections are also different.
ABSTRACT
WGA-HRP was iontophoretically delivered into various parts of the habenular nuclei (the lateral segment of the lateral habenular nucleus LHb-L, the medial segment of the lateral habenular nucleus LHb-M, and the medial habenular nucleus MHb) in 40 rats to study the route and distribution of the anterograde labeled fibers and terminals in the brain. The efferent projections of the habenular nuclei follow three routes, the rostral, contralateral and caudal pathways. Along the rostral pathway fibers leave the lateral habenular nucleus, follow the stria medullaris thalami rostrally, and distribute to the thalamic dorsomedial nucleus, paratenial nucleus and lateral preoptic area. Fibers from the contralateral pathway distribute to the opposite lateral habenular nucleus by way of the commissura habenularum Fibers in the caudal pathway originate mainly from the MHb and LHb-M, and distribute to the interpeduncular nucleus with a dorsoventral topographic localization. In addition some of the caudal efferent fibers run caudally and terminate in the raphe nuclei and reticular formation etc.