下丘脑室旁核经迷走神经复合体对哮喘大鼠的神经调控研究

为探讨下丘脑室旁核对哮喘大鼠的神经调控途径,取健康雄性SD大鼠制备哮喘模型并诱发哮喘发作,运用WGA-HRP逆行追踪法与免疫组织化学染色法(ABC法)相结合的双重标记方法,在光镜下观察向迷走神经复合体(DVC)发出投射的下丘脑室旁核(PVN)神经元内Fos蛋白的表达情况。结果显示:PVN内有三种阳性细胞,即HRP逆行标记神经元、Fos样免疫阳性神经元和HRP/Fos双标神经元。这些神经元主要见于PVN小细胞部的内侧亚核和外侧亚核,散在分布于背侧亚核,在前小细胞亚核内未见阳性反应;Fos样免疫阳性细胞呈双侧分布,且HRP逆标神经元,HRP/Fos双标神经元也为双侧分布,但以注射区同侧占优势。HRP/Fos双标神经元占HRP标记细胞的44.22%。本研究结果提示,哮喘大鼠发作时中枢内包括下丘脑PVN、延髓DVC的多个脑区内神经元兴奋,且两者之间通过直接投射联系参与哮喘的调控。     

内脏伤害性刺激后Fos在大鼠脑内NOS阳性神经元内的表达

目的：观察一氧化氮合酶(NOS)阳性神经元在内脏伤害性信息传递通路上的分布。方法：给予大鼠内脏伤害性刺激后，采用Fos免疫组织化学(ABC法)和还原型尼克酰胺腺嘌呤二核苷酸脱氢酶(NADPH-d)组织化学双重染色的方法，观察脑内NOS和Fos阳性神经元的分布。结果：脑内Fos／NOS双标阳性神经元主要分布在孤束核，中缝背核，丘脑室旁核，下丘脑室旁核、室周核、背内侧核，中脑导水管周围灰质腹外侧部、背外侧部，臂旁内侧核，内侧缰核，杏仁复合体内侧部等部位。结论：NO是内脏伤害性信息传递和调控通路上的神经递质之一。     

延髓内脏带儿茶酚胺能神经元对LPS免疫刺激的Fos表达

目的　探讨“延髓内脏带 (MVZ)至下丘脑室旁核 (PVN)”的儿茶酚胺能通路在“免疫 脑通讯”中的作用。　方法　应用WGA HRP逆行追踪与抗Fos和抗酪氨酸羟化酶 (TH)抗体双重免疫组织化学相结合的三重标记方法 ,即先将WGA HRP注入大鼠一侧PVN内 ,存活 4 8h后经腹腔注射免疫刺激剂脂多糖 (LPS)诱发免疫反应后 ,观察MVZ中WGA HRP逆标细胞、Fos蛋白和儿茶酚胺能神经元 (以TH为标记物 )的分布及表达状况。　结果　在MVZ内发现 7种阳性神经元 ,即HRP、Fos、TH单标细胞、Fos HRP、Fos TH、HRP TH双标细胞和Fos HRP TH三标细胞。Fos HRP双标记和Fos HRP TH三标记细胞分别占总HRP逆行标记细胞的 12 5 %和 39 6 %。　结论　MVZ对LPS免疫刺激起反应 ,并可能将免疫信息经儿茶酚胺能神经元上传至PVN ;MVZ可能作为“免疫 脑通讯”的一个中继站 ,通过“MVZ→PVN”通路起免疫调节作用。     

一氧化氮合酶在大鼠杏仁基外侧核传入神经元内的分布

目的：研究一氧化氮合酶(NOS)在大鼠杏仁基外侧核(BLA)传入投射神经元中的分布。方法：采用霍乱毒素B亚单位(CTb)逆行追踪和还原型尼克酰胺腺嘌呤二核苷酸脱氢酶(NADPH—d)组织化学双重染色相结合的方法。结果：双标神经元(NADPH-d／CTb)主要分布在孤束核、蓝斑、臂旁内侧核、中缝背核、中央灰质背侧部、丘脑室旁核、下丘脑室旁核、下丘脑室周核、下丘脑腹内侧核以及杏仁内侧核等神经核团。结论：NOS在大鼠BLA传人投射神经元中主要分布于上述核团,并且提示NO参与BLA的功能调节。     

热应激时下丘脑视上核和室旁核Fos蛋白的表达

为了探讨不同温度下,大鼠的行为表现及大鼠下丘脑视上核和室旁核内神经元Fos蛋白的表达情况,本研究将成年SD大鼠置于不同温度(24℃、34℃、38.5℃、42℃),相对湿度为60%的实验仓内60min,观察大鼠的行为表现;同时应用免疫组化染色技术,观察大鼠下丘脑视上核和室旁核内Fos阳性神经元的形态、分布和数量的变化。行为学结果显示:24℃时,大鼠无异常表现,直肠温度为36℃左右;34℃仅引起大鼠直肠温度升高至38℃左右,动物行为无明显变化;38.5℃和42℃时,大鼠直肠温度升高至39℃以上,最初大鼠精神萎靡,活动减少,但随后转为兴奋状态,出现惊跳、逃窜行为。免疫组化染色结果显示:24℃时,下丘脑视上核、室旁核内Fos阳性细胞较少;34℃时,Fos阳性细胞的表达量增加;38.5℃时,Fos阳性细胞数达到峰值;42℃时又降低,并出现三种Fos阳性细胞:即胞核为Fos阳性、胞浆为Fos阳性以及胞浆、胞核均为Fos阳性。以上结果表明下丘脑视上核、室旁核内Fos蛋白的表达随温度的升高而发生明显的变化,提示这两个核团参与了热应激过程。     

去窦弓神经后大鼠臂旁核亚核内Fos和NADPH-d的分布

目的探讨大鼠臂旁核神经型一氧化氮合酶是否参与减压反射的调节。方法用Fos蛋白免疫组织化学结合还原型尼克酰胺腺嘌呤二核苷酸脱氢酶(NADPH-d)组织化学双重染色的方法,观察去窦弓神经后Fos和NADPH-d在臂旁核各亚核内的分布情况。结果与假手术组和正常对照组相比,臂旁外侧核外亚核、内侧核外亚核和K-F核内Fos免疫阳性反应明显增强。在这些Fos阳性神经元的表面通常可见NADPH-d阳性纤维终末分布,但偶见Fos和NADPH-d双标神经元。结论臂旁外侧核外亚核、内侧核外亚核和K-F核内部分神经元可被去窦弓神经术特异性激活;一氧化氮可能主要通过突触前机制参与此刺激的传递过程。     

含后叶加压素的视上核神经元及含P物质的中缝背核神经元至下丘脑室旁核投射的研究

用HRP逆行追踪与免疫细胞化学结合的方法,对某些投射至大鼠下丘脑室旁核的神经元的化学性质进行了研究.结果显示在视上核内存在三种标记细胞:HRP单标细胞、后叶加压素免疫反应阳性单标细胞和HRP后叶加压素双标细胞.双标细胞为大、中型椭圆形或圆形细胞,约占HRP标记细胞总数的22%.在中缝背核投射至室旁核的神经元中,部分为P物质免疫反应阳性,双标细胞为中小型梭形细胞,约占HRP标记细胞总数的20%.上述结果提示:视上核有后叶加压素能神经元、中缝背核有P物质能神经元投射到室旁核.     

NOS在大鼠杏仁皮质核传入神经元内的分布

目的研究一氧化氮合酶(NOS)在杏仁皮质核传入投射神经元中的分布。方法采用霍乱毒素B亚单位(CTb)逆行追踪和还原型尼克酰胺腺嘌呤二核苷酸脱氢酶(NADPH-d)组织化学双重染色相结合的方法。结果双标神经元(NADPH/CTb)主要分布在孤束核(Sol)、蓝斑(LC)、臂旁内侧核(MPB)、中缝背核(DR)、中央灰质外侧部(CGL)、中央灰质背侧部(CGD)、丘脑室旁核(PV)、下丘脑室旁核(Pa)、下丘脑室周核(Pe)、下丘脑腹内侧(VMH)核以及杏仁内侧核(ME)等神经核团。结论NOS在大鼠杏仁皮质核传入投射神经元中主要分布于上述核团,并且提示NO参与杏仁皮质核的功能调节。     

大鼠延髓至下丘脑室旁核的儿茶酚胺能投射神经元在胃伤害性刺激后的FOS表达

用ＨＲＰ注入下丘脑室旁核逆行追踪与抗Ｆｏｓ和抗酪氨酸羟化酶（ＴＨ）双重免疫细胞化学相结合的三重标记方法，对大鼠孤束核和延髓腹外侧区至下丘脑室旁核的儿茶酚胺能投射神经元对胃伤害性刺激后的ｃ－ｆｏｓ表达进行了观察，发现孤束核和延髓腹外侧区有７种不同的标记细胞：ＨＲＰ、Ｆｏｓ、ＴＨ单标细胞，Ｆｏｓ／ＨＲＰ、Ｆｏｓ／ＴＨ、ＨＲＰ／ＴＨ双标细胞，Ｆｏｓ／ＨＲＰ／ＴＨ三标细胞。上述７种标记细胞主要分布在延髓中、尾段孤束核的内侧亚核、连合亚核和延髓腹外侧区以及两者之间的网状结构。ＨＲＰ标记细胞以注射侧为主，对侧有少量分布。本文结果证明，大鼠孤束核和延髓腹外侧区至下丘脑室旁核投射的部分儿茶酚胺能神经元可能参与胃伤害性刺激的传导和调控。     

大鼠展神经核和前庭神经核内GABA反应神经元向动眼神经核的投射

用辣根过氧化物酶(horseradish peroxidase,HRP)逆行标记结合γ-氨基丁酸(γ-amino-butyric acid,GABA)的免疫组织化学双标技术观察大鼠的展神经核和前庭神经核内GABA阳性神经元的分布,以及其向动眼神经核的投射。结果表明:注射HRP于大鼠动眼神经核内直肌亚核后,在对侧展神经核区以及前庭神经核、脑桥旁正中网状结构中发现HRP单标记细胞;在前庭神经核内,可见HRP单标记、GABA阳性和HRP/GABA双标记三类神经元,其中HRP/GABA双标记细胞占HRP标记细胞总数的47.1%。结果表明GABA在前庭神经核向动眼神经核的抑制性投射中起一定作用,而在展神经核向动眼神经核投射的核间通路中,可能不是起主要作用的抑制性神经递质。     

Evidence for the medullary visceral zone as a neural station of neuroimmunomodulation

The aim of the present study was to test the possibility that the catecholaminergic projectional pathway from the vagus nerve to the medullary visceral zone (MVZ) thence to the paraventricular nucleus of hypothalamus (PVN) was involved in the cytokine-to-brain communication. A triple labeling method in which WGA-HRP retrograde tracing was combined with anti-Fos and -TH immunohistochemical staining was used. WGA-HRP was stereotaxically injected into unilateral PVN in the rat, after a survival of 48 h, animals received intraperitoneal injection of lipopolysaccharide (LPS). The distribution of the HRP retrogradely labeled neurons, Fos protein positive and catecholaminergic neurons (tyrosine hydroxylase as marker) in the MVZ was observed. Subdiaphragmatic vagotomy (SDV) and sham surgery were also used to observe the different Fos expression in the MVZ after intraperitoneal administration of lipopolysaccharide (LPS) or pyrogen-free saline (NS). Under light microscope, seven types of positively stained neurons could be distinguished within the MVZ, namely neurons single-labeled with Fos, HRP or TH, respectively; neurons double-labeled with Fos/TH, Fos/HRP or HRP/TH separately; and neurons triple-labeled with Fos, HRP and TH staining. Intraperitoneal LPS caused lots of robust Fos expression within the MVZ in the sham surgery groups and this response in the MVZ was markedly inhibited in the vagotomized rats. The results suggested that some catecholaminergic neurons in the MVZ could send projections to the PVN and this pathway might be involved in the relay of peripheral immune information via vagus nerve. MVZ was a neural relay station in the immune-to-brain communication and might play a significant role in the neuroimmunomodulation via vagus-MVZ-PVN pathway.     

Acute ethanol induces Fos in GABAergic and non-GABAergic forebrain neurons: a double-labeling study in the medial prefrontal cortex and extended amygdala

The purpose of this study was to further address the hypothesis that ethanol activates GABAergic neurons in specific brain neurocircuits that mediate motivated behavior and control of action, such as the central extended amygdala and medial prefrontal cortex. Male Sprague-Dawley rats received habituation to 7 days of daily intragastric administration of water (5 ml/kg) followed by a single acute intragastric dose of ethanol (2.5 g/kg) or water then, 2 h later, by paraformaldehyde perfusion. Rats left undisturbed in the animal room throughout the experiment were also perfused (naive group). Brain sections were processed for single Fos immunohistochemistry or dual Fos immunohistochemistry/glutamic acid decarboxylase (GAD) mRNA in situ hybridization. Intragastric water administration increased the number of Fos-immunoreactive cells in the infralimbic cortex and lateral part of the central nucleus of the amygdala compared with the naive group. Ethanol administration increased the number of Fos-immunoreactive cells in the infralimbic (+57.5%) and prelimbic (+105.3%) cortices, nucleus accumbens shell region (+88.2%), medial part of the central nucleus of the amygdala (+160%), and lateral part of the bed nucleus of the stria terminalis (+198.8%) compared with the water-treated group. In the nucleus accumbens shell region, central nucleus of the amygdala, and bed nucleus of the stria terminalis, more than 80% of Fos-immunoreactive neurons were GABAergic after ethanol administration. In contrast, in the prelimbic cortex, 75% of Fos-immunoreactive neurons were not GABAergic. These results constitute new evidence for region-specific functional interactions between ethanol and GABAergic neurons.     

Histochemical identification of a PVN-hindbrain feeding pathway

Unilateral coronal knife cuts through the ventrolateral pontine reticular formation produce overeating and overweight when combined with contralateral parasagittal knife cuts in the medial hypothalamus (MH). The knife cuts were in a position to sever fiber projections from the paraventricular nucleus to the hindbrain. The present study used histochemical techniques to confirm that hyperphagia-producing knife cuts transect PVN-hindbrain fiber connections. In Experiment 1, adult female rats received a unilateral coronal knife cut in the ventrolateral pontine reticular formation. Horseradish peroxidase (HRP) was applied to the knife cut region and two to three days later brains were processed for the localization of neurons labeled with HRP. HRP-labeled neurons were found in the PVN, particularly in the caudal parvocellular region. Additional HRP-labeled neurons were observed in other medial hypothalamic areas but none were found in the ventromedial nucleus. HRP-filled cells were also found in the lateral hypothalamus, central nucleus of the amygdala, and in the nucleus of the solitary tract (NST). Many of the PVN projections to the hindbrain contain oxytocin and Experiment 2 determined if hyperphagia-inducing knife cuts sever PVN oxytocinergic fibers. Adult female rats received unilateral MH cuts, unilateral pontine cuts, or a contralateral combination of both cuts. One to eight days later the brains were processed for immunocytochemistry. The MH cuts and pontine cuts were found to interrupt descending oxytocinergic fibers. Taken together, these results support the hypothesis that interruption of a direct PVN-hindbrain oxytocinergic projection is responsible for the hypothalamic hyperphagia-obesity syndrome. However, the results do not rule out the involvement of a multisynaptic pathway or additional neurochemical systems.     

Fos expression in neurons immunoreactive for neuronal nitric oxide synthase in the rat paraventricular nucleus after intraperitoneal injection of interleukin-1 beta

Double immunostaining for Fos and neuronal nitric oxide synthase (nNOS) was used to examine whether nNOS-immunoreactive neurons in the paraventricular hypothalamic nucleus (PVN) are activated to express Fos immunoreactivity by intraperitoneal injection of interleukin-1 beta (IL-1 beta) in the rat. Quantitative analysis revealed that some nNOS-positive PVN neurons are activated by IL-1 beta (4 microg/kg, i.p.) administration, but the majority of the IL-1 beta-activated PVN neurons do not express nNOS and are distributed mainly in the parvocellular part of the PVN.     

“Green odor” inhalation by rats down-regulates stress-induced increases in Fos expression in stress-related forebrain regions

In the present study, on rats, a quantitative analysis of Fos protein immunohistochemistry was performed as a way of investigating the effects of inhalation of green odor (a mixture of equal amounts of trans-2-hexenal and cis-3-hexenol) on the neuronal activations in stress-related forebrain regions induced by acute and repeated stress. Rats were exposed to restraint stress for 90 min each day for 1, 2, 4, 7, or 11 consecutive days. The hypothalamic paraventricular nucleus (PVN), amygdala, hippocampus and paraventricular thalamic nucleus (PVT) were examined. Both acute and repeated restraint stress increased Fos-positive cells in the entire hypothalamic PVN, in the central and medial amygdala, and in PVT, although these responses declined upon repeated exposure to such stress. The stress-induced Fos responses were much weaker in rats that inhaled green odor during each day's restraint. No increases in Fos-positive cells were observed in the hippocampus in acutely stressed rats. The Fos-immunoreactive response to acute stress shown by the piriform cortex did not differ significantly between the vehicle + stress and green + stress groups. Green odor had inhibitory effects on the stress-induced corticosterone response, body-weight loss, and adrenal hypertrophy. These results suggest that in rats, green odor inhalation may, in an as yet unknown way, act on the brain to suppress activity in the neuronal networks involved in stress-related responses (such as activation of the hypothalamo–pituitary–adrenocortical axis and activation of the sympathetic nervous system, as well as stress-induced fear responses).     

大鼠下丘脑室旁核GABA_A Rα1阳性神经元参与内毒素诱导的免疫应激反应

为探讨下丘脑室旁核(PVN)内GABAA受体α1亚单位(GABAARα1)阳性神经元是否参与内毒素(LPS)诱导的免疫应激反应,本研究采用腹腔注射LPS建立免疫应激模型,对照组注射等量的生理盐水,应用免疫荧光双标记与激光共聚焦显微镜技术,观察两组大鼠下丘脑PVN内Fos和GABAARα1阳性神经元的形态、分布和数量的变化以及Fos和GABAARα1阳性神经元之间的关系。结果显示:LPS可使大鼠PVN内Fos阳性神经元数量显著增高,GABAARα1阳性神经元的染色增强,且其中的部分神经元同时表达Fos和GABAARα1;经计数Fos/GABAARα1双标阳性神经元的比例占Fos阳性神经元的27%,占GABAARα1阳性神经元的32%。本实验结果提示PVN内的部分GABAARα1阳性神经元参与了由LPS诱导的免疫应激反应,说明GABA可能通过GABAA受体在免疫应激反应中发挥作用。上述结果为阐明免疫应激反应时GABAAR在下丘脑-垂体-肾上腺轴中的作用提供了形态学基础。     

Mating behavior induces selective expression of Fos protein within the chemosensory pathways of the male Syrian hamster brain.

The effect of mating behavior on the expression of Fos protein was analyzed within the chemosensory pathways of the male Syrian hamster brain. Following a single mating test, the number of Fos-immunoreactive (Fos-ir) neurons increased within the amygdala, bed nucleus of the stria terminalis and medial preoptic area. The mating-induced pattern of Fos expression within these brain regions shows a strong correlation with the sites of lesions that eliminate or alter mating behavior. In addition, Fos expression was increased within the paraventricular nucleus of the hypothalamus. These results provide the first demonstration of a dynamic and selective pattern of neuronal activity within specific nuclei known to be essential for mating behavior in the male Syrian hamster.