Central alpha-melanocyte stimulating hormone attenuates behavioral effects of neuropeptide Y in chicks

This experiment was conducted to determine the effects of central alpha-melanocyte stimulating hormone (alpha-MSH) and its interaction with neuropeptide Y (NPY) on ingestive and non-ingestive behaviors in chicks. Chicks received intracerebroventricular injections of either 0, 0.12 nM alpha-MSH, 0.06 nM NPY, or 0.12 nM alpha-MSH+0.06 nM NPY. Immediately following injection, chicks were placed in an observation arena and the number of steps, jumps, feed pecks, drinks, exploratory pecks, escape attempts, the total distance traveled, and the amount of time spent standing, sitting, sleeping, and preening were monitored for 60 min. Chicks treated with NPY consumed 69% more feed than controls whereas alpha-MSH-treated chicks consumed 71% less. Feed intake of the NPY+alpha-MSH groups was similar to alpha-MSH-treated chicks at 66% less than aCSF-treated chicks. Differences in pecking were found and followed a similar pattern as feed intake. All treatments increased the amount of time chicks were in a sitting posture, and the alpha-MSH+NPY group spent more time sitting than alpha-MSH and NPY alone. The sitting response after alpha-MSH+NPY treatment was similar to the alpha-MSH group but not the NPY group. Other behaviors were not affected by treatment. Thus, we conclude that alpha-MSH, at a concentration that causes a similar magnitude decrease in feed intake as NPY increases feed intake, is a more potent appetite-related signal than NPY. alpha-MSH causes behavioral effects that may secondarily affect feed intake at a low magnitude and may modulate the behavioral effects of NPY in chicks, contributing to the overall effect on feed intake.     

Effects of intracerebroventricular infusion of genistein on gonadotrophin subunit mRNA and immunoreactivity of gonadotrophins and oestrogen receptor-α in the pituitary cells of the anoestrous ewe

The present study was designed to demonstrate whether genistein, a synthetic phytoestrogen, infused into the third ventricle of the brain could affect the gonadotrophic cells regarding the presence of oestrogen receptor-α immunoreactivity and gonadotrophin subunit mRNA hybridising reaction in the ewe. Ewes (n = 7), aged 2 years, in early anoestrous season were infused with Ringer–Locke solution (control, n = 3) or 10 μg/100 μl/h of genistein (n = 4) into the third ventricle over a 5 h period and slaughtered the following morning. Immunoreactivity of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and oestrogen receptor-α (ERα) was determined in the adenohypophysis by immunohistochemistry using antibodies raised against LHβ, FSHβ, and ERα. Messenger RNA analyses were performed by non-isotope in situ hybridisation using sense and antisense riboprobes produced from β subunits of LH and FSH cDNA clones. Computer image analysis was used to determine the percent of cells exhibiting immunohistochemical and/or hybridising reaction. It was found that in ewes infused with genistein, the percentage of LH-positive cells and the density of immunoreactive-LHβ material decreased significantly (P ≤ 0.001), but the percentage of mRNA LHβ-expressing cells and the intensity of the hybridisation signal increased significantly (P ≤ 0.001), compared to the vehicle-infused animals. The genistein infusions had no effect on the immunoreactivity of FSH cells or on the expression of mRNA for FSHβ. The percentage of ERα-positive cells increased significantly after genistein infusions (P ≤ 0.001) and this increase was significant in the LH but not in FSH cells (P ≤< 0.001). In conclusion, we suggest that genistein can stimulate the expression of immunoreactive ERα in the pituitary LH-cells but not in FSH-cells and change the endocrine activity of LH-producing cells of anoestral ewes.     

神经肽Y刺激血管平滑肌增殖和losartan的干预作用

目的：搪塞神经肽Ｙ和肾素－血管紧张素系统之间的相互作用与高血压疾病发生之间的关系。方法：应用快速微量ＭＴＴ比色法和荧光免疫组化定量技术,观察神经肽Ｙ对体外２血管平滑肌细胞增殖活度和血管平滑肌细胞核细胞增殖的表达的影响以及血管临终素Ⅱ受体拮抗剂ｌｏｓａｒｔａｎ对其影响的干预作用,结果：神经肽Ｙ可刺激体外２血管平滑肌的增殖、使其增殖活度（ＭＴＴ－ＯＤ值）和细胞内核增殖怕（ＰＣＮＡ）的表达明显高于对照组     

Effect of follicle stimulating hormone treatment on the pituitary response to luteinizing hormone-releasing hormone in post-menopausal women

To study the role of exogenous follicle stimulating hormone(FSH) in the attenuation of luteinizing hormone (LH) responseto luteinizing hormone-releasing hormone (LHRH) during ovulationinduction in women, 10 healthy post-menopausal women were treatedwith FSH (225 IU/day) for 5 days and normal saline (2 ml/day)for another 5 days. The two regimens were given consecutivelyin a 10 day experiment. The regimen for the first 5 days wasrandomly chosen and was given to the women in an alternate way.The response of LH to an i.v. injection of 10 µg LHRHwas investigated twice on day 1 (i.e. before the onset of treatmentand 12 h later) and once on days 2, 5 and 10 of the experiment(0900 h). Basal FSH and LH values before the onset of treatmenton day 1 were similar in the five women who started with thesaline and the five who started with the FSH regimen. BasalFSH values increased significantly during treatment with FSH,while LH and oestradiol values remained unchanged throught thewhole experiment. LH increment 30 min post –LHRH did notchange significantly either during the first 24 h or duringthe whole experiment regardless of the starting regimen. Theseresults demonstrate that in post-menopausal women the responseof LH to LHRH is not affected by exogenous administration ofFSH. It is suggested that exogenous FSH does not show activitieson gonadotrophin secretion similar to those ascribed to a gonadotrophinsecretion similar to those ascribed to a gonadotrophin surgeattenuating factor.     

Galanin-like peptide is co-localized with alpha-melanocyte stimulating hormone but not with neuropeptide Y in the rat brain

Ultrasound can be heard by bone conduction in man. However, there has been no consensus about the perception mechanism of bone-conducted ultrasound (BCU). In the current study, to clarify the central auditory system of BCU, the effects of stimulus duration for 30 kHz BCU on N1m were compared with those for air-conducted 1 kHz tone bursts by magnetoencephalography. As a result, the growth of N1m amplitude for both stimuli saturated at the duration of 40 ms, which suggest that the temporal integration system of BCU is similar to that of audible sound. However, significant differences in the growth were observed below the saturation points. The results indicate a possibility that there are some differences in the central auditory system between BCU and audible sound.     

Prepubertal changes in the synthesis, storage and release of growth hormone and luteinising hormone and in the immunoreactivity of oestrogen receptor-alpha in lamb pituitary cells. A morphofunctional study

The present study was designed to determine the changes in the synthesis, storage and release of luteinising hormone (LH) and growth hormone (GH) in the hypophyseal cells by investigating the presence of oestrogen receptor-alpha (ERalpha) in developing prepubertal female lambs. The experiment was carried out on 14 prepubertal (17-week-old) and 14 peripubertal (32-week-old) ovary-intact lambs. Morphofunctional changes in the cells of the adenohypophyseal population were assayed with immunohistochemistry (IH), in situ hybridisation (ISH), Real-time PCR and radioimmunoassay (RIA). Blood samples (n=14) were taken every 2 weeks from 17 to 32 weeks of age for estimation of GH and LH by RIA. Computer image analysis was used to determine the percent of cells exhibiting IH and/or ISH reaction. The percentage of cells stained for LHbeta and GH increased for both LH- and GH-producing cells and were higher (P<0.001) in the peripubertal than prepubertal group. The percentage of mRNA LHbeta-expressing cells decreased and were lower for the peripubertal (P<0.001) than prepubertal group. The GH mRNA in pituitaries of prepubertal lambs was higher in comparison to peripubertal ones (P<0.001). The percentage of ERalpha positive cells increased significantly (P<0.001) in peripubertal compared to prepubertal lambs and this increase was significant (P<0.001) in both LH- and GH-producing cells. Plasma LH concentrations increased from 27 weeks of age, while GH concentrations gradually decreased from 17 weeks of age (P<0.05). The histomorphological changes in the LH- and GH-producing cells reflect the increasing pattern of the regulation of secretory processes of these hormones and an escalating regulatory role of oestrogen in the physiology of these cells during the prepubertal period. These results support the involvement of both hormones in the events leading up to puberty.     

环胞霉素A抑制神经肽Y诱导大鼠心肌细胞肥大效应

目的:观察Ca²⁺/CaM依赖的钙调神经磷酸酶(CaN)抑制剂环胞素A(CsA)对神经肽Y诱导心肌细胞肥大效应的影响。方法:用神经肽Y(NPY)刺激Wistar乳鼠心肌细胞,并用环胞素A加以干预。应用氚-亮氨酸([³H]-Leu)掺入法测定心肌细胞蛋白质合成速率、RT-PCR法测心肌细胞c-junmRNA表达。结果:(1)心肌细胞氚-亮氨酸([³H]-Leu)掺入量测定:与对照组相比,NPY10nmol/L组氚-亮氨酸([³H]-Leu)掺入量有所增高,但与对照组比无显著差别,而NPY100nmol/L组心肌细胞氚[³H]-Leu掺入量较对照组明显增高(P＜0.05)。CsA组和对照组相比无显著差别。(2)心肌细胞内c-junmRNA表达:NPY组心肌细胞c-junmRNA的RT-PCR产物量明显高于对照组和CsA组(P＜0.01),对照组和CsA组间无显著差别。结论:NPY刺激心肌细胞蛋白质合成增加、心肌细胞原癌基因(肥大早期反应基因)c-junmRNA表达,提示NPY可诱导心肌细胞肥大;CaN抑制剂CsA可阻断NPY上述效应,说明Ca²⁺/CaM依赖的CaN信号途径在其中起重要作用。     

Losartan对神经肽Y诱导血管平滑肌

目的:观察神经肽Y(NPY)与血管紧张素受体拮抗剂losartan对体外培养的血管平滑肌细胞(VSMC)中PCNA、PDGF、c-myc癌基因表达的影响,从分子生物学的角度探讨NPY在高血压、动脉粥样硬化发生中的作用和losartan的逆转作用。方法:应用荧光免疫组化定量技术(ACAS570共聚焦激光扫描显微细胞仪)。结果:NPY刺激VSMC增殖,使其PCNA、PDGF和c-myc癌基因的表达明显高于对照组;losartan则可逆转NPY对VSMC增殖的刺激作用,使PCNA、PDGF和c-myc癌基因表达的平均荧光值降低。结论:NPY促进VSMC的增殖,其作用与高血压的发生有关;而losartan对高血压的治疗作用可能与拮抗NPY对VSMC增殖的刺激作用有关。     

Morphological evidence for neuronal regulation of luteinizing hormone-releasing hormone-containing neurons by neuropeptide Y in the rat septo-preoptic area

Using a preembedding double immunolabeling technique, synaptic contacts were found between luteinizing hormone-releasing hormone (LHRH)-containing neurons and neuropeptide Y-containing axonal fibers in the rat septo-preoptic area. In demonstrating LHRH neurons, we used mainly an antiserum generated against rat gonadotrophic hormone-releasing hormone-associated peptide. Although many diaminobenzidine-labeled neuropeptide Y-containing fibers were seen around silver-gold-labeled LHRH cell bodies, synapses with synaptic membrane specialization were scarce. The fiber terminals usually contained many small clear vesicles and some large cored vesicles. The synapses were characterized with the presynaptic accumulation of the small clear vesicles and symmetric thickenings of the synaptic membranes.     

In vitro effects of neuropeptide Y in rat neocortical and hippocampal tissue

Neuropeptide Y (NPY) network effects in hippocampus and frontal cortex and its impact on epileptiform neocortical discharges were investigated in rat juvenile brain slices. NPY (1 μM) reduced amplitudes of paired pulse stimulation in hippocampal brain tissue (p<0.05) whereas NPY (1 nM-2 μM) had no effect in neocortex. Late stage epileptiform activity in the neocortex was unaffected by NPY (1 μM). Our results point to a region dependent effect of NPY with a high impact on hippocampal and minimal impact on neocortical networks.     

Current concepts of the roles of follicle stimulating hormone and luteinizing hormone in folliculogenesis

Around 400 follicles sequentially mature and ovulate duringan average women‘s reproductive lifetime. From birth tothe menopause, the other 99.98% of her follicles begin developmentbut never complete it. Instead they default to atresia due toinadequate stimulation by follicle stimulating hormone (FSH).Follicular growth to the stage of antrum formation (0.25 mmdiameter) is independent of gonadotrophic stimulation. Antrumformation and further growth to the stage at which folliclesbecome potentially able to begin pre-ovulatory development (2–5mm diameter) require tonic stimulation by FSH. Before onsetof puberty, blood concentrations of FSH do not rise sufficientlyto sustain development beyond this stage, therefore all antralfollicles become atretic. After puberty, as each menstrual cyclebegins, FSH concentrations rise beyond a critical ‘threshold’and multiple follicles are recruited to begin pre-ovulatorydevelopment. Due to increases in its responsiveness to FSH andluteinizing hormone (LH), one of these follicles becomes selectedto ovulate while the remainder become atretic. At mid-follicularphase, the dominant follicle reaches 10 mm in diameter and increasinglysynthesizes oestradiol. Tonic stimulation by FSH and LH, underpinnedby local paracrine signalling, maintains oestrogen secretionby the dominant follicle, which grows to 20 mm in diameter beforeit ovulates in response to the mid-cycle LH surge. The development-relatedresponse to LH shown by the pre-ovulatory follicle raises thepossibility that exogenous LH might be used as an adjunct totherapy with exogenous FSH in clinical ovulation induction regimenswhere the aim is to induce monovulation.     

Tyrosine hydroxylase-immunoreactivity and its relations with gonadotropin-releasing hormone and neuropeptide Y in the preoptic area of the guinea pig

The present study examines the distribution of tyrosine hydroxylase (TH) immunoreactivity and its morphological relationships with neuropeptide Y (NPY)- and gonadoliberin (GnRH)-immunoreactive (IR) structures in the preoptic area (POA) of the male guinea pig. Tyrosine hydroxylase was expressed in relatively small population of perikarya and they were mostly observed in the periventricular preoptic nucleus and medial preoptic area. The tyrosine hydroxylase-immunoreactive (TH-IR) fibers were dispersed troughout the whole POA. The highest density of these fibers was observed in the median preoptic nucleus, however, in the periventricular preoptic nucleus and medial preoptic area they were only slightly less numerous. In the lateral preoptic area, the density of TH-IR fibers was moderate. Two morphological types of TH-IR fibers were distinguished: smooth and varicose. Double immunofluorescence staining showed that TH and GnRH overlapped in the guinea pig POA but they never coexisted in the same structures. TH-IR fibers often intersected with GnRH-IR structures and many of them touched the GnRH-IR perikarya or dendrites. NPY wchich was abundantly present in the POA only in fibers showed topographical proximity with TH-IR structures. Althoug TH-IR perikarya and fibers were often touched by NPY-IR fibers, colocalization of TH and NPY in the same structures was very rare. There was only a small population of fibers which contained both NPY and TH. In conclusion, the morphological evidence of contacts between TH- and GnRH-IR nerve structures may be the basis of catecholaminergic control of GnRH release in the preoptic area of the male guinea pig. Moreover, TH-IR neurons were conatcted by NPY-IR fibers and TH and NPY colocalized in some fibers, thus NPY may regulate catecholaminergic neurons in the POA.     

The value of basal serum follicle stimulating hormone, luteinizing hormone and oestradiol concentrations following pituitary down-regulation in predicting ovarian response to stimulation with highly purified follicle stimulating hormone.

The value of gonadotrophin and oestradiol concentrations following pituitary down-regulation with leuprolide acetate in predicting ovarian response to stimulation was evaluated in three groups of women undergoing ovarian stimulation for in-vitro fertilization with highly purified follicle stimulating hormone (FSH). Leuprolide acetate was started in the midluteal phase, and either stopped at menses (IVF-SL group, n = 3), or continued throughout stimulation (IVF-LL group, n = 38; oocyte donors, n = 58). Ovarian stimulation was started on cycle day 3, after blood was drawn for down-regulated FSH, luteinizing hormone (LH) and oestradiol. Higher down-regulated LH was predictive of higher oestradiol on day 5 of stimulation in both IVF groups, and of need for fewer ampoules in the IVF-LL group, but not of oestradiol on day of human chorionic gonadotrophin (HCG) administration or number of oocytes retrieved. Higher FSH after down-regulation predicted yield of fewer oocytes in the donor and IVF-LL groups, and higher oestradiol on day 5 of stimulation, need for fewer ampoules and a shorter duration of therapy in both IVF groups. Higher oestradiol after down-regulation was associated with higher oestradiol on day 5 of stimulation and on day of HCG administration, a shorter duration of therapy and need for fewer ampoules in all groups. Whereas these results do not ascribe any predictive significance to LH, they suggest that oestradiol and FSH concentrations after down-regulation are predictive of the pattern of ovarian response to stimulation and of oocyte yield.     

Neuroprotection by neuropeptide Y in cell and animal models of Parkinson's disease

This study was aimed to investigate the potential neuroprotective effect of neuropeptide Y (NPY) on the survival of dopaminergic cells in both in vitro and in animal models of Parkinson's disease (PD). NPY protected human SH-SY5Y dopaminergic neuroblastoma cells from 6-hydroxydopamine-induced toxicity. In rat and mice models of PD, striatal injection of NPY preserved the nigrostriatal dopamine pathway from degeneration as evidenced by quantification of (1) tyrosine hydroxylase (TH)-positive cells in the substantia nigra pars compacta, levels of (2) striatal tyrosine hydroxylase and dopamine transporter, (3) dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) as well as (4) rotational behavior. NPY had no neuroprotective effects in mice treated with Y(2) receptor antagonist or in transgenic mice deficient for Y(2) receptor suggesting that NPY effects are mediated through this receptor. Stimulation of Y(2) receptor by NPY triggered the activation of both the ERK1/2 and Akt pathways but did not modify levels of brain derived neurotrophic factor (BDNF) or glial cell line-derived neurotrophic factor. These results open new perspectives in neuroprotective therapies using NPY and suggest potential beneficial effects in PD.     

Characterization of NPY mRNA-expressing cells in the human brain: co-localization with Y2 but not Y1 mRNA in the cerebral cortex, hippocampus, amygdala, and striatum

Neuropeptide Y (NPY) is one of the most abundant peptides in the central nervous system. Its effects on, for example, cognition, memory and motor functions are thought to be mediated mainly via its interactions with the NPY Y1 and Y2 receptor subtypes. We had previously described the neuroanatomical organization of the Y1 and Y2 mRNA expression in humans. However, in view of the lack of information regarding the overall detailed distribution of NPY mRNA expression in the human brain, a complete picture of the anatomical organization of the NPY-related genes was still missing. Thus, in the present study, the regional distribution of NPY mRNA-expressing cells was analyzed in the post-mortem human brain. In addition, double labeling in situ hybridization was performed to characterize the NPY neuronal populations in relation to the Y1 and/or Y2 receptor mRNA localization in the human cerebral cortex, striatum, and amygdala. NPY mRNA was found to be abundant in layers II and VI of the neocortex, polymorphic layer of the dentate gyrus, basal ganglia, and amygdala. Double labeling in situ hybridization showed the co-expression of NPY mRNA with the Y2, but not with the Y1, mRNA in the human cerebral cortex, hippocampus, amygdala, striatum, and nucleus accumbens, and the existence of co-expression of the Y1 and Y2 mRNAs in the cerebral cortex and amygdala. Overall, these results suggest a role for the Y2, but not Y1, as an autoreceptor in the NPY neuronal populations of the human brain.     

神经肽Y对bcl-2、bax、fas基因表达和血管平滑肌细胞增殖的作用

目的:研究神经肽Y(NPY)对细胞凋亡相关基因表达和细胞增殖的作用。方法:应用生物化学比色法和荧光免疫组化定量技术观察NPY对血管平滑肌细胞(VSMC)中细胞凋亡相关基因bcl-2、bax及fas表达和细胞核增殖抗原(PCNA)的平均荧光值。结果:NPY作用下,细胞凋亡相关基因bcl-2、bax和fas表达及VSMC的增殖活度和PCNA明显高于对照组。结论:NPY可影响VSMC细胞凋亡的相关基因表达及增殖活动。     

低氧预适应后小鼠海马神经肽Y及突触的变化

目的 探讨低氧预适应产生神经保护作用的机制。方法 将小鼠随机分为对照组（H0组）和低氧组（H4组）,H4组为通过整体重复低氧建立的小鼠低氧预适应动物模型,H0组不进行低氧处理。用免疫组织化学方法检测小鼠海马神经肽Y(NPY)及突触体素（SYP）的表达,电镜观察海马CA1区的不对称突触和穿通型不对称突触形态及数量。结果 与H0组相比较,H4组海马NPY阳性细胞数量有中等量增多(n=30),SYP阳性细胞数量有明显增多(n=30),而海马CA1区的不对称突触和穿通型不对称突触数量减少(n=6)。结论 低氧预适应后海马的这些变化可能降低了神经元的兴奋性,从而增强了脑抵抗低氧/缺血的能力而产生神经保护作用。     

Co-existence of neuropeptides and differential inhibition of vasodilator responses by neuropeptide Y in guinea pig uterine arteries

The co-localization of substance P (SP) with calcitonin gene-related peptide (CGRP), and vasoactive intestinal peptide (VIP) with neuropeptide Y (NPY) of the guinea pig uterine artery were investigated with immunocytochemistry. The SP/CGRP fibre population was distinct from the VIP/NPY fibre population. Both types of fibres ran in the medial-adventitial border, and appeared as coarsed and fine varicosed. Uterine arterial dilatation was evoked by acetylcholine (ACh), SP, CGRP, and VIP in precontracted arteries as examined by a sensitive in vitro method. Strong relaxations were seen by ACh, CGRP and VIP. NPY had no relaxant effect per se but was found to be a potent inhibitor of vasodilation induced by ACh and SP, while relaxations induced by VIP and CGRP were unaffected. The functional significance of NPY in the uterine artery may to a large extent be to increase tension not only by potentiation of contraction but additionally by inhibiting vasodilator responses.     

无精与严重少精症Y染色体AZF区域微缺失与生殖激素的关系

目的 探讨Y染色体AZF区域微缺失与生殖激素的关系.方法 应用多重PCR扩增对100例无精与严重少精症患者的4个区域15个位点进行AZF基因检测,并采用贝克曼全自动化学发光仪进行生殖激素的测定.采用Epidata建立数据库,应用SAS软件进行均数和方差分析F检验的统计分析.结果 100例患者中发生AZF微缺失的患者13...