Unexpected high density of neuropeptide Y Y1 receptors in the guinea pig spleen

Receptors for neuropeptide Y (NPY) and peptide YY (PYY) have been extensively characterized in the brain. Less is known about NPY receptor subtypes in the spleen, though it is well established that NPY produces vascular contraction in this tissue. In the present study, we found an unusually high density of Y₁ receptors in the guinea pig spleen. These receptors are localized to the red pulp and exhibit a pharmacology that is consistent with the Y₁ receptor. On the other hand, only very low densities for Y₂ receptors were observed. Therefore, the guinea pig spleen may be a ideal tissue for further study of the role of Y₁ receptors in cardiovascular and immune function.     

Species differences in the reflex effects of lingual afferent nerve stimulation on lip blood flow and arterial pressure

We evoked changes in lower lip blood flow and systemic arterial blood pressure by electrically stimulating the central cut end of the lingual nerve in artificially ventilated, urethane-anesthetized, cervically vago-sympathectomized cats, rats, rabbits, and guinea pig. The systemic arterial blood pressure changes were species-dependent: increases in rat, consistent decreases in rabbit and guinea pig, and variable among individuals in cat. In cat and rabbit, lip blood flow increases, which occurred only ipsilaterally to the stimulated nerve and showed no statistically significant correlation with the systemic arterial blood pressure changes. In rat, the ipsilateral lip blood flow increase was markedly greater than the contralateral one, and although there was a significant correlation between each of them and the systemic arterial blood pressure changes, the ipsilateral increase presumably included an active vasodilatation. In guinea pig, lip blood flow decreased on both sides in proportion to the systemic arterial blood pressure reductions. Thus, species variability exists in the sympathetic-mediated systemic arterial blood pressure changes and parasympathetic-mediated lip blood flow responses themselves, and in the relationship between them.Abbreviations a.u. arbitary units - LBF lip blood flow - LN lingual nerve - SABP systemic arterial blood pressure - SP substance P - Vsp trigeminal spinal nucleusCommunicated by I.D. Hume     

Neuropeptide Y immunoreactivity in the mammalian liver: pattern of innervation and coexistence with tyrosine hydroxylase immunoreactivity

Summary The distribution of nerve fibers displaying neuropeptide Y immunoreactivity in relationship to the catecholaminergic innervation of rat, guinea pig, and rabbit liver was investigated by single- and double-label immunofluorescence methods. In all three species, neuropeptide Y-immunoreactive fibers are prominent in association with the vasculature, biliary pathway, and stromal compartment. The neuropeptide Y innervation of the parenchyma, on the other hand, differs among the three species in term of density. It is quite sparse in the rat and rabbit, particularly in the former species. In the guinea pig liver, numerous single, varicose neuropeptide Y-containing nerve fibers innervate the hepatic parenchyma; often, thin processes surround single hepatocytes and lie close to sinusoids. The immunoreactive pattern of tyrosine hydroxylase, a marker for catecholaminergic neurons and fibers, is comparable to that of neuropeptide Y. Most neuropeptide Y-containing nerve fibers also contain tyrosine hydroxylase immunoreactivity, in all three species, with the exception of the rabbit parenchyma, where a substantial proportion of catecholaminergic fibers lack immunoreactivity for neuropeptide Y. Finally, systemic administration of the sympathetic neurotoxin, 6-hydroxydopamine, in rats and guinea pigs resulted in virtually complete elimination of both neuropeptide Y- and tyrosine hydroxylase-immunoreactive fibers. These findings are consistent with the hypothesis that neuropeptide Y-containing nerve fibers form a subpopulation of the sympathetic innervation of the mammalian liver, which is likely to originate from prevertebral sympathetic ganglia.     

Angiostrongylus cantonensis: Rejection of pulmonary arterial transfers of lung stage worms

Experimental transfer of the lung stage worms of Angiostrongylus cantonensis was performed between permissive hosts (rats) and between permissive (rat) and nonpermissive hosts (guinea pigs and rabbits). These worms from rats were rejected when implanted into nonpermissive hosts. Unexpectedly, similar worms did not survive well even in permissive hosts; the majority of recipient rats did not have first-stage larvae (L₁) in their stools and, even when positive for L₁, the number of the larvae shed was few. These findings contrast with the successful pulmonary arterial transfer of younger, intracranial-stage worms. It was shown that differences in rat strain between donor and recipient had no significant effect on the subsequent worm survival in recipient hosts. The alteration of maintaining conditions of the intrapulmonary worms, prior to transfer, in terms of temperature, media, and maintaining period, also showed no profound effect on the subsequent worm survival. The kinetics of precipitating and reaginic antibody levels in rats implanted with the intrapulmonary worms were analogous to those in rats with intracranial-stage worms. The findings indicate that some qualitative differences may exist between the worms obtained from two different sites.     

Distribution and origin of substance P and neuropeptide Y-immunoreactive nerves in the guinea-pig heart

Summary The localization and origin of substance P (SP)-, neuropeptide Y (NPY)-, and noradrenaline/tyrosine hydroxylase (NA/TH)-immunoreactive (IR) nerves in the guinea-pig heart were investigated by means of immunohistochemistry; quantitative analysis was performed by radioimmunoassay (NPY) and high performance liquid chromatography (NA). Both untreated animals and animals subjected to stellatectomy, combined stellatectomy and local capsaicin pretreatment of the vagal nerves or systemic application of capsaicin were studied. A dense network of SP-IR nerves was observed in the right atrium in different locations: (1) around local cardiac ganglion cells, (2) close to blood vessels, (3) within the myocardium, and (4) close to and within peri and endocardium.A moderately dense SP-innervation, mainly related to blood vessels, was found in the ventricles. Very dense networks of NPY and TH-IR nerve fibers with an overlapping distributional pattern around blood vessels and in the myocardium were seen in both the atria and the ventricles. In addition, some cell bodies in local cardiac ganglia were NPY-IR. Bilateral stellatectomy resulted in a reduction of SP-IR in the right atrium (55% of control), which was more pronounced after additional capsaicin pretreatment of the vagal nerves (44% of control).In the left ventricle no significant depletion of SP-IR was seen by either stellatectomy or combined stellatectomy and capsaicin treatment of the vagal nerves. It was not possible to establish any defined target areas within the heart for vagal or spinal SP-IR afferents by use of immunohistochemical methods. Systemic capsaicin treatment caused a total loss of SP-IR nerves in the heart. After bilateral stellatectomy the levels of NPY-IR and NA were reduced to about 10% of control in both the right atrium and left ventricle. In accordance, NPY and TH-IR nerves were also almost totally absent in the heart after bilateral stellatectomy.     

几种实验动物骨骼肌肌球蛋白ATP酶与SDH酶染色的比较

本文为研究ATP酶和SDH酶两种反应法在骨骼肌分型方面的异同。在兔、豚鼠、大白鼠和小鼠的腓肠肌的恒冷连续切片中,取相邻的两片分别做ATP酶和SDH酶反应,然后选取两片相对应部位做显微摄片,并进行比较。结果显示:两种酶反应中,Ⅰ型纤维的吻合率是83％,Ⅱ型纤维的吻合率为68％。本文认为,ATP酶和SDH酶两种反应所作的分型不能视为等同。     

A Comparison of the Binding of [3H]Proprionyl-Neuropeptide Y to Rat and Human Frontal Cortical Membranes

The binding characteristics of [3H]proprionyl-neuropeptide Y ([3H]proprionyl-NPY) were studied in frontal cortical membranes prepared from rat and human postmortem tissue. The specific binding of NPY decreased as the magnesium concentration increased from 1.05 to 10 mM. The binding was also influenced by the concentration of GTP in the buffer medium, with a resulting 45% decrease in NPY binding in the presence of 10(-6) M GTP. Using equilibrium binding studies, [3H]proprionyl-NPY was found to bind in both tissues with high affinity to a single class of receptors with a similar KD (0.035 nM). However, kinetic experiments in both tissues provided evidence for two components of [3H]proprionyl-NPY binding which may be related to receptor states. Competition binding experiments showed that peptide YY (PYY) was equal to NPY in its ability to displace [3H]proprionyl-NPY, whereas rat and human pancreatic polypeptide were without effect up to a concentration of 10(-6) M. This suggests that, whereas PYY and NPY may compete for the same receptor(s), the pancreatic polypeptides probably act on a separate population of receptors.     

神经肽Y免疫反应神经和细胞在大鼠颌下腺的分布

本研究应用免疫组织化学ＡＢＣ技术,观察了含神经肽Ｙ神经和细胞在大鼠颌下腺内的分布特点。结果显示：含神经肽Ｙ神经纤维主要走行于腺泡、导管及血管周围。颌下腺内神经节细胞和颗粒曲管细胞亦呈神经肽Ｙ免疫反应阳性。提示：大鼠颌下腺的腺体分泌和血液供应可能受神经肽Ｙ能神经调控。     

氟骨症不同动物模型的建立与评价

目的 为选择合适的实验动物并建立氟骨症动物模型,研究不同动物对氟化物致骨骼损伤的敏感性.方法 分别选取离乳新西兰兔、Hartley豚鼠、Wistar大鼠、KM小鼠各16只,每种动物随机分为两组,每组8只,即对照组(C):饲喂标准饲料,饮用去离子水;模型组(M):饲喂标准饲料,饮用150 mg/L氟化钠(NaF)去离子水.在饲喂60 d后取股骨制作组织切片观察组织形态变化,并测定股骨骨氟、骨钙、骨磷的含量及血清碱性磷酸酶(ALP)活性.结果 与对照组相比,各种实验动物模型组生长发育受到显著的抑制,股骨形态破坏明显,骨矿化显著减少,骨氟含量显著升高,血清ALP活性显著增强,但股骨钙和磷含量差异无显著性(P＞0.05).结论 高氟可不同程度的损害豚鼠、家兔、小鼠、大鼠的生长发育及骨骼系统,导致产生氟骨症,但综合考察,以豚鼠、家兔较为敏感,其次为小鼠、大鼠.     

Peripheral insulin administration attenuates the increase in neuropeptide Y concentrations in the hypothalamic arcuate nucleus of fasted rats

Fasting increases neuropeptide Y (NPY) concentrations in the arcuate nucleus (ARC), its site of synthesis, and in other regions of the rat hypothalamus. Neuropeptide Y is a potent central orexigenic agent and may therefore stimulate appetite during fasting. We tested the hypothesis that low plasma insulin levels stimulate ARC levels of NPY in fasted rats. Compared with freely fed controls (n = 8), rats fasted for 72 h (n = 8) showed significantly lower plasma insulin levels (28.9 ± 1.6 vs. 52.6 ± 5.7 pmol/l; p < 0.001) and higher ARC NPY concentrations (14.2 ± 1.8 vs. 8.4 ± 2.2 fmol/μg protein; p < 0.001). Fasted rats treated with subcutaneous insulin (5 U/kg/day; n = 10), which nearly normalized plasma insulin (46.6 ± 2.8 pmol/l), showed intermediate ARC NPY levels (11.2 ± 1.4 fmol/μg protein; p < 0.01 vs. controls and untreated fasted rats). Insulin administered peripherally, therefore, attenuates fasting-induced NPY increases in the ARC, supporting the hypothesis that hypoinsulinemia stimulates hypothalamic NPY.     

Age-Related Bidirectional Changes in Neuropeptide Y Peptides in Rat Adrenal Glands, Brain, and Blood

Age-related changes in neuropeptide Y (NPY) regulation were studied in rat adrenal glands, brains, and blood by radioimmunoassay and biochemical characterization using reversed phase HPLC and gel filtration chromatography. NPY immunoreactivity (pmol/g tissue +/- SEM) in rat adrenal glands increased from 7 +/- 1 (6 weeks old) to 1,500 +/- 580 (69 weeks old). Biochemical characterization by HPLC showed that this increase was due to those of NPY and methionine sulfoxide NPY. In contrast, in rat brain, NPY content decreased in an age-dependent manner specifically in striatum, hippocampus, medulla oblongata, and spinal cord and the sulfoxide form was not detected. In rat blood, the circulating level of NPY was high (3-5 pmol/ml plasma +/- SEM) but did not change significantly with age or by adrenal demedullation. Only a small increase of the sulfoxide form of NPY was observed in aged rat plasma. The age-dependent changes in regulation and modification of NPY in adrenal glands and in specific brain areas may have physiological relevance in the regulation of catecholamine release from adrenal glands and some brain functions during aging.     

The relationship between gastrin cells and bombesin-like immunoreactive nerve fibres in the gastric antral mucosa of guinea-pig,rat, dog and man

Summary The relationship between bombesin-like immunoreactive (bombesin-LI) nerve fibres and gastrin-LI G-cells was examined in gastric antral mucosa from guineapig, rat, dog and man using a double-labelling fluorescence immunohistochemical technique. The greatest density of bombesin-LI nerve fibres was found within the basal mucosa in all species and the density of innervation decreased towards the luminal surface. Most G-cells were in a band occupying approximately the middle third of the mucosa. The proportion of G-cells found within a distance of 2 m from bombesin-LI nerve fibres was low in all species (6% in the guinea-pig, 22% in the rat, 14% in the dog, and 9% in the human). It is proposed that the neuropeptide released from bombesin-LI antral mucosal nerve fibres traverses distances of greater than several m to reach the target G-cells. This may be achieved by passage through the mucosal microcirculation.     

Separation and identification of neuropeptide Y, two of its fragments and their degradation products using capillary electrophoresis–mass spectrometry

This paper describes the development of an analytical method for the separation and identification of neuropeptide Y (NPY) and two important NPY fragments by capillary electrophoresis (CE) and mass spectrometry (MS). A satisfactory separation and the highest sensitivity were obtained with formic acid at high concentrations (250 mM, pH 2.75). The addition of 25 or 50 mM triethylamine (TEA) improved the separation. When applying full scan CE–MS, the separated peptides could be detected and identified using the spectra of each peak. The use of TEA as an additive to the formic acid slightly decreased the sensitivity but was compensated by the improved efficiency. The best compromise for optimal separation and MS detection was found to be 50 mM formic acid to which 50 mM TEA was added. CE–MS could be used for identification of the decomposition products of NPY. Decomposition products with one amino acid difference, which could not be distinguished with CE–UV, could be distinguished with CE–MS.     

Heterogeneity of [3H]Dipyridamole Binding to CNS Membranes: Correlation with [3H]Nitrobenzylthioinosine Binding and [3H]Uridine Influx Studies

The relationship between the nucleoside transport system and the nitrobenzylthioinosine-sensitive and -resistant [3H]dipyridamole binding sites was examined by comparing the characteristics of [3H]dipyridamole binding with those of [3H]nitrobenzylthioinosine binding and [3H]-uridine influx in rabbit and guinea pig cerebral cortical synaptosomes. Two distinct high-affinity synaptosomal membrane-associated [3H]dipyridamole binding sites, with different sensitivities to inhibition by nitrobenzylthioinosine, were characterized in the presence of 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS, 0.01%) to prevent [3H]dipyridamole binding to glass tubes and filters. The nitrobenzylthioinosine-resistant [3H]-dipyridamole binding sites represented a greater proportion of the total membrane sites in guinea pig than in rabbit (40 vs. 10% based on inhibition studies). In rabbit, nitrobenzylthioinosine-sensitive [3H]dipyridamole binding (KD = 1.4 +/- 0.2 nM) and [3H]nitrobenzylthioinosine binding (KD = 0.30 +/- 0.01 nM) appeared to involve the same membrane site associated with the nitrobenzylthioinosine-sensitive nucleoside transporter. By mass law analysis, [3H]-dipyridamole binding in guinea pig could be resolved into two components based on sensitivity to inhibition by 1 microM nitrobenzylthioinosine. The nitrobenzylthioinosine-resistant [3H]dipyridamole binding sites were relatively insensitive to inhibition by all of the nucleoside transport substrates and inhibitors tested, with the exception of dipyridamole itself. In guinea pig synaptosomes, 100 microM dilazep blocked nitrobenzylthioinosine-resistant [3H]uridine transport completely but inhibited the nitrobenzylthioinosine-resistant [3H]dipyridamole binding component by only 20%. Furthermore, a greater percentage of the [3H]dipyridamole binding was nitrobenzylthioinosine resistant in guinea pig compared with rabbit, yet both species had a similar percentage of nitrobenzylthioinosine-resistant [3H]uridine transport.(ABSTRACT TRUNCATED AT 250 WORDS)     

大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育

本实验用免疫组织化学ＡＢＣ法研究了大鼠胼胝体内神经肽Ｙ免疫反应阳性（ＮＰＹ－ＩＲ）纤维的生后发育。结果发现,许多ＮＰＹ－ＩＲ纤维在大鼠出生时便存在于胼胝体内。ＮＰＹ－ＩＲ胼胝体纤维的密度在生后１周内继续逐渐增高,在第２周内达到最高峰。之后,ＮＰＹ－ＩＲ胼胝体纤维的密度逐渐下降,至第３周末时接近成年时的水平,即仅有少量ＮＰＹ－ＩＲ纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多ＮＰＹ－ＩＲ胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。     

自发性高血压鼠脑底动脉神经肽Y能神经纤维的起源

应用免疫组织化学ABC法和神经节切除术,观察了16只自发性高血压鼠（分手术Ⅰ、Ⅱ、Ⅲ组和对照组）脑底动脉主要分支神经肽Y能神经纤维的起源,对照组自发性高血压鼠大脑前动脉,大脑中动脉,大脑后动脉和基底动脉壁上均可见棕褐色的神经肽Y能阳性纤维,纤维似曲线状,多呈网状走行,密度较高,手术Ⅰ组作双侧颈上神经节切除术,脑底动脉主要分支的阳性纤维明显减少,但不完全消失,手术Ⅱ组作双侧星状神经节切除术,脑底动脉主要分支壁上的阳性纤维明显减少;手术Ⅲ组作双侧颈上神经节和星状神经节切除术,脑底动脉主要分支的阳性纤维完全消失,结果提示;自发性高血压鼠脑底动脉主要分支神经肽Y能神经纤维起源于双侧颈上神经节和星状神经节,讨论了NPY神经在高血压时期在防御脑中风和血脑屏障破裂方面所起的作用。     

Neuropeptide Y: An Endogenous Inhibitor of Norepinephrine-Stimulated Melatonin Secretion in the Rat Pineal Gland

The biosynthesis of the hormone melatonin (MEL) by the mammalian pineal gland has been thought to be regulated strictly by stimulatory factors, most predominantly norepinephrine (NE), released from the sympathetic nerve fibers which heavily innervate the gland. Evidence from many investigators suggests that sympathetic fibers may colocalize other neuroactive factors in addition to NE. One of these factors is neuropeptide Y (NPY), which has been found in the nerve fibers of the pineal gland. The present study sought to explore potential interactions between NE and NPY in the regulation of pineal MEL secretion. Specific, saturable, and reversible binding of 125I-NPY to intact cultured pinealocytes was measured with an affinity constant of 1 nM and an NPY binding site density of 0.04 pmol/mg of protein. In addition, cell culture studies revealed that NPY represents a potent (IC50 of 0.4 nM) endogenous inhibitor of NE-stimulated MEL secretion. However, this inhibition is accompanied by only a modest reduction (35%) of cyclic AMP accumulation. These findings reinforce the view that the mammalian pineal gland, which appears to integrate both inhibitory as well as stimulatory signals, is an important model of autonomic function, particularly in the context of biological rhythmicity.     

Conversion of Neuropeptide K to Neurokinin A and Vesicular Colocalization of Neurokinin A and Substance P in Neurons of the Guinea Pig Small Intestine

The highest concentration of neurokinin A-like immunoreactivity and substance P-like immunoreactivity in the guinea pig small intestine was associated with the myenteric plexus-containing longitudinal muscle layer. Chromatographic analysis of extracts of this tissue demonstrated the presence of neurokinin A and neuropeptide K but the probable absence of neurokinin B. A fraction of synaptic vesicles of density 1.133 +/- 0.003 g/ml was prepared from the myenteric plexus-containing tissue by density gradient centrifugation in a zonal rotor and was enriched 29 +/- 12-fold in the concentration of neurokinin A-like immunoreactivity and 43 +/- 13-fold in the concentration of substance P-like immunoreactivity. This fraction was separated from the fraction of vasoactive intestinal peptide-containing vesicles (density, 1.154 +/- 0.009 g/ml). Chromatographic analysis of lysates of the vesicles indicated the presence of neurokinin A but not neuropeptide K. It is postulated that beta-pre-protachykinin is processed to substance P, neurokinin A, and neuropeptide K in the cell bodies of myenteric plexus neurons but that conversion of neuropeptide K to neurokinin A takes place during packaging into storage vesicles for axonal transport. The data are consistent with the proposal that neurokinin A and substance P are stored in the same synaptic vesicle, but the possibility of cosedimentation of different vesicles of very similar density cannot be excluded.     

改良的Cajal金升汞染色法显示纤维性星形胶质细胞

目的探索一种快捷、简便、稳定的染色方法显示脑组织内纤维性星形胶质细胞。方法取猫、家兔、大鼠和豚鼠的大脑组织,部分组织采用传统的Cajal金升汞法制片。部分组织采用改良Cajal金升汞法制片。结果与传统Cajal金升汞法比,应用改良Cajal金升汞染色法,缩短了制片时间,纤维性星形胶质细胞染色均匀,结构清晰,胶质细胞纤维显现明显,分枝光滑,较长突起末端膨大的脚板终止于血管壁上。结论应用改良后的Cajal金升汞法染色显示纤维性星形胶质细胞效果明显优于传统Cajal金升汞法。