A hypothalamic-pituitary system that stimulates the release of plasminogen activator in the rat

We have studied the possible role of the hypothalamic-pituitary system in the control of the release of plasminogen activator (PA) into peripheral blood of male rats. Plasminogen activator was measured by euglobulin lysis time. Desamino-D- arginine vasopressin (dDAVP) and adrenaline injected i.v. induced an increase in plasma PA as did electrical stimulation of the median eminence (ME), but dDAVP had no effect on plasma PA in hypophysectomized rats. The PA response to ME stimulation was similar in Brattleboro rats (deficient in vasopressin) and adrenalectomized Wistar rats compared with intact Wistar rats, but was abolished by section of the pituitary stalk and was negligible in hypophysectomized rats. The 41-residue corticotropin releasing factor (CRF) had no effect on PA release. Saline extracts of anterior pituitary gland from both normal Wistar and Brattleboro rats produced a dose-dependent increase in plasma PA when injected into normal Wistar rats. The activity of pituitary tissue was abolished by boiling, but not by di-isopropyl fluorophosphate which inactivates PA itself. Thus the anterior pituitary gland of the rat contains a heat-labile factor which stimulates the release of PA from peripheral stores into the circulation. This pituitary factor is released by a hypothalamic factor that is neither vasopressin nor CRF.     

Differential expression of vasopressin receptor binding in the hypothalamus during lactation in golden hamsters

Vasopressin (AVP) receptor binding within hypothalamic sites was compared between cycling and lactating female golden hamsters. The density of AVP receptor binding was analyzed by quantitative autoradiography within the ventrolateral hypothalamus and dorsomedial hypothalamic nucleus. Lactation was correlated with a disappearance of AVP receptor binding within the ventrolateral hypothalamus. In contrast, lactation was associated with a two- to three-fold increase in the density of AVP receptor binding within the dorsomedial hypothalamic nucleus. These results suggest that AVP receptor binding within the ventrolateral hypothalamus is responsive to gonadal hormones in female golden hamsters. However, the increase in binding observed within the dorsomedial hypothalamus may be related to other neurobiological changes associated with lactation.     

Distribution and hypothalamic projection of tyrosine-hydroxylase containing neurons of the nucleus of the solitary tract in the pigeon.

The avian nucleus of the solitary tract has an extensive subnuclear organization. Several subnuclear cell groups can be distinguished on the basis of cytoarchitectonic criteria. In general, the subnuclei of the medial division of the nucleus of the solitary tract receive gastrointestinal afferents, whereas the subnuclei of the lateral division of the nucleus of the solitary tract receive cardiopulmonary afferents. Forebrain afferents to the nucleus of the solitary tract are segregated to medial and lateral subnuclei, which are located at the periphery of the nucleus. These peripheral subnuclei of the nucleus of the solitary tract are also the source of ascending axonal projections to the forebrain. In this study, the tyrosine hydroxylase (initial enzyme for catecholamine synthesis) content of the anteromedial hypothalamic projecting neurons of the nucleus of the solitary tract is determined by use of a combined retrograde fluorescent dye-immunofluorescence method. Fast Blue implanted into the anteromedial hypothalamus (in the region of the nucleus periventricularis magnocellularis) resulted in the retrograde labeling of neurons in the caudal two-thirds of the nucleus of the solitary tract. At levels rostral to the obex, dye-labeled cells were mostly observed in the dorsally located subnuclei medialis superficialis pars posterior and lateralis dorsalis pars posterior and in the ventrally located subnucleus medialis ventralis pars posterior. More centrally located subnuclei contained few labeled cells, if any. For example, subnucleus medialis intermedius pars posterior only had a few retrogradely labeled cells, whereas the centrally located subnucleus medialis dorsalis pars posterior was almost devoid of labeled cells. At levels caudal to the obex, many retrogradely labeled neurons of the nucleus of the solitary tract were observed. Neurons immunoreactively labeled for tyrosine hydroxylase were mostly found within subnuclei, which contain anteromedial hypothalamic projection neurons. In subnuclei medialis superficialis pars posterior and lateralis dorsalis pars posterior, 87% of the retrogradely dye-labeled cells were also immunoreactively labeled, whereas in the caudal nucleus of the solitary tract (at levels caudal to the obex), 68% of the retrogradely labeled cells were immunoreactively labeled. Not all tyrosine hydroxylase containing cells had projections to the implantation site in the anteromedial hypothalamus since only 40% of the immunoreactive cells in the caudal nucleus of the solitary tract and 59% of the immunoreactive cells in the subnucleus medialis superficialis pars posterior were retrogradely labeled with Fast Blue.(ABSTRACT TRUNCATED AT 400 WORDS)     

Fine structural studies of growth-hormone-releasing-factor (GRF)-immunoreactive neurons and their synaptic connections in the guinea pig arcuate nucleus

The fine structure of neurons containing human growth-hormone-releasing factor (hGRF) immunoreactivity located in the arcuate nucleus of the guinea pig was studied by means of the preembedding immunohistochemical technique. The perikaryon of labeled neurons was fusiform or ovoid; the nucleus was regular in shape and contained a prominent nucleolus. The main ultrastructural features of the hGRF-immunoreactive neurons were the presence of numerous labeled secretory granules (100-120 nm in diameter) and the abundance and the enlargement of the organelles involved in the synthesis of the peptides: a well-developed rough endoplasmic reticulum and a conspicuous Golgi apparatus. Synaptic inputs were observed on immunoreactive perikarya but, above all, on the labeled dendrites. The unstained presynaptic nerve endings most often contained only small clear vesicles and formed symmetrical contacts. In rare cases, the presynaptic terminals exhibited both small clear and large dense vesicles and constituted asymmetrical contacts. Immunoreactive nerve endings were also observed in this area: the synaptic boutons contained large, stained vesicles and small, unlabeled, clear vesicles. These axon terminals made synaptic contacts with unstained dendritic processes; the contacts were symmetrical. The results indicate that hGRF-immunoreactive neurons of the guinea pig arcuate nucleus present morphological features of neuroendocrine cells. Moreover, the presence of hGRF-labeled nerve endings in the arcuate nucleus itself suggests that a substance related to hGRF might be a neuromodulator, at least in this area.     

环境温度变化对去卵巢大鼠下丘脑视上核和室旁核c-Fos蛋白表达的影响

目的:以不同温度刺激去卵巢大鼠,观察下丘脑视上核(SO)和室旁核(PVN)细胞c-Fos蛋白表达的变化,探讨更年期妇女血压、渗透压以及体温调节功能异常的可能机制.方法:将去卵巢(OVX)和假手术(Sham)大鼠分别置于4,10,25,33和38℃5个温度等级的培养箱内,2 h后取脑.采用免疫组织化学法检测各实验组SO和...     

Impulse activity of individual sensorimotor cortex neurons in rabbits after microiontophoretic administration of antibodies against acid fibroblast growth factor

We studied the sensitivity of sensorimotor cortex neurons in rabbits to microiontophoretic administration of antibodies against acid fibroblast growth factor (anti-aFGF). Spontaneous activity and reaction of neurons to electrical stimulation of ‘feeding centers’ in the lateral hypothalamic area (LHA) were recorded. We analyzed impulse activity of 52 neurons in the sensorimotor cortex. It was shown that 14 neurons (25%) reacted to microiontophoresis of anti-aFGF (excitation and inhibition in 9 and 5 neurons, respectively). Microiontophoretic administration of anti-aFGF did not change the reaction (excitation or inhibition) of 27 neurons to electrical stimulation of LHA. Initially, 14 neurons did not response to LHA stimulation. After microiontophoretic administration of anti-aFGF, 6 of 14 neurons displayed pronounced reactions to electrical stimulation of LHA (excitation and inhibition in 2 and 4 neurons, respectively). These data suggest that aFGF plays an important physiological role in feeding motivations.     

电刺激大鼠下丘脑室旁核对胃缺血-再灌注损伤的影响

采用夹闭大鼠腹腔动脉30min，松开动脉夹血流复灌1h的胃缺血－再灌注损伤模型，观察了电刺激和电损毁下丘脑室旁核（paraventricular nucleus,PVN)对大鼠胃缺血－再灌注损伤（gastric ischemia-reperfusion injury,GI-RI的影响，并对其作用机制进行了初步探讨。结果表明：电刺激PVN后GI－RI显著减轻，且有强度－效应依赖关系；PVN内注射胞体兴奋剂L－谷氨酸后，与电刺激PVN的效应相同；电解损毁双侧PVN则能加重GI－RI；电刺激PVN能显著降低GI－RI大鼠的胃粘膜丙二醛（MDA）含量及胃液酸度和胃蛋白酶活性，但对其超氧化物歧化酶（SOD）的活性及胃液量、总酸排出量、胃整结合粘液量无显著影响。提示PVN对GI－RI具有保护作用，其作用机制可能与降低GI－RI大鼠的胃粘膜MDA含量、胃蛋白酶活性、胃液酸度有关，而与胃液量、总酸排出量、胃壁结合粘液量等因素无明显关系。     

大鼠下丘脑室旁核一氧化氮和外周血白细胞介素1β含量的昼夜节律变化及相关性的探讨

目的:探讨大鼠外周血白细胞介素1β(IL-β)和下丘脑室旁核中的一氧化氮是否具有昼夜节律以及两者的相关性。材料和方法:成年雄性SD大鼠24只随机分为4组,分别在16:00、22:00、4:00和10:00时腹腔注射细菌脂多糖。两小时后,分别麻醉采血及灌注取脑。采用放射免疫分析法测定外周血IL-1β的含量,运用β-NADPH-酶组化和计算机图像分析技术对室旁核中NADPH-d阳性神经元的切面面积和平均灰度值进行分析。结果:1.6:00时组外周血IL-1β含量最高,12:00时组最低,显示出明显的昼夜节律性。2.四组大鼠室旁核内NADPH-d阳性神经元的切面面积12:00时组最大,18:00时组最小,差异有显著性。3.外周血IL-1β含量昼夜节律变化的时相比室旁核一氧化氮产生量昼夜节律变化的时相早6小时。结论:大鼠外周血中IL-1β和室旁核一氧化氮的产生量均有昼夜节律性变化,外周血中IL-1β可能对室旁核一氧化氮的产生有促进作用。     

新兵训练后功能性闭经女兵的心身症状与激素水平

目的:探讨新人伍女兵功能性下丘脑性闭经(FHA)者与月经正常者激素水平及心理健康状况的差异。方法:在某部队新人伍女兵98人接受了为期近4个月的体能训练之后,有54人出现闭经.其中闭经3个月以上者有35人(研究组)。训练后月经正常、在采血时月经周期处于第5～11天者有26人(对照组)。分别测定她们血清中的促卵泡生成素(FSH)、黄体生成素(LH)、雌二醇(E_2)、孕酮(P)、泌乳素(PRL)、睾酮(T)、ACTH、T_3、T_4的水平,并用SCL-90分别评定她们的心理健康状况。结果:FHA 者血清FSH 值为4.96±1.73 mIU/ml,LH 值为2.63±1.78 mIU/ml,E_2的值为7.23±5.37 pg/ml,对照组血清相应值为10.73±2.30mIU/ml、12.31±2.15mIU/ml、41.67±6.13pg/ml,差异有统计学意义(P<0.01),闭经组低于对照组。FHA 组SCL-90的躯体化、人际敏感、抑郁、焦虑及其他因子分大于2的比率分别为:51.4%、42.9%、48.6%、51.4%及37.1%;而对照组这5项分值大于2的比率分别为15.4%、15.4%、19.2%、21.3%及11.5%,两组间这5个因子大于2的人数差异有统计学显著意义(P<0.05),闭经组高于对照组。结论:诊断为FHA 的女兵与月经正常女兵的激素水平有差异,闭经组心身症状的发生率也高于对照组。     

小鼠室旁核内雌激素受体与催产素、加压素表达的免疫组化研究

目的研究雌激素的核受体ER-α和ER-β以及催产素、加压素在成年雌性小鼠下丘脑室旁核内的表达。方法采用硫酸镍铵增强显色的免疫组化SP法检测ER-α、ER-β、催产素和加压素在室旁核内的表达。结果雌激素的两种核受体在室旁核内都有表达,但是以ER-β为主（P〈0.001）,其免疫阳性产物均在细胞核内,未见核外免疫阳性反应。催产素的免疫阳性产物主要在细胞核周围的胞浆即核周质内,而加压素的免疫阳性物质除了在核周质内有很强的反应外,在突起内也可见很强的免疫反应。ER-α的免疫阳性胞体主要在大细胞部内侧,而ER-β、催产素和加压素的免疫阳性胞体主要在背侧帽部或大细胞部的外侧。结论室旁核内两种雌激素受体可能都参与了对催产素和加压素的调节,但ER-β可能发挥了主要的调节作用。