Mechanisms underlying pre- and postjunctional effects of neuropeptide Y in sympathetic vascular control

The effects of porcine neuropeptide Y (NPY) regarding sympathetic vascular control were studied in vitro on isolated rat blood vessels. The 10(-9)M NPY enhanced (about two-fold) the contractile responses to transmural nerve stimulation (TNS), noradrenaline (NA) and adrenaline (about two-fold) in the femoral artery. Higher concentrations of NPY (greater than 10(-8)M) caused an adrenoceptor-resistant contraction per se. The TNS-evoked [3H]NA efflux was significantly reduced by NPY in a concentration-dependent manner (threshold 10(-9)M). The calcium antagonist, nifedipine, abolished the contractile effects of NPY and the NPY-induced enhancement of NA contractions but did not influence the prejunctional inhibition of [3H]NA release. Receptor-binding studies showed that the ratio of alpha 1-to alpha 2-adrenoceptors in the femoral artery was 30:1. The NPY did not cause any detectable change in the number of alpha 1-or alpha 2-adrenoceptor binding sites or in the affinity of alpha 2-binding sites, as revealed by prazosin- and clonidine-binding, respectively. The NPY also inhibited the TNS-evoked [3H]NA release (by 42-86%) in the superior mesenteric and basilar arteries and in femoral and portal veins. The NPY still depressed TNS-evoked [3H]NA secretion from the portal vein in the presence of phentolamine. The NPY caused a clear-cut contraction in the basilar artery, increased the contractile force of spontaneous contractions in the portal vein, while only weak responses were observed in the superior mesenteric artery and femoral vein. The NA-induced contraction was markedly enhanced by NPY in the superior mesenteric artery, only slightly enhanced in the portal vein and uninfluenced in the femoral vein. In conclusion, in all blood vessels tested, NPY depresses the TNS-evoked [3H]NA secretion via a nifedipine-resistant action. Furthermore, NPY exerts a variable, Ca2+-dependent vasoconstrictor effect and enhancement of NA and TNS contractions.     

A sympathetic reflex elicited by distension of the mesenteric venous bed

1. The proximal ends of the distal portions of severed nerves coming from the small intestine were monitored for nerve impulses. When the mesenteric venous pressure was increased by mechanical obstruction of the portal vein there was a proportional increase in the frequency of afferent action potentials, the frequency falling immediately the venous pressure was reduced. The stimulus for the increased rate of nerve discharge appeared to be pressure within the mesenteric venous bed and not anoxia, for obstruction of the arterial supply to the gastrointestinal tract did not activate the same fibres.2. Obstruction of the portal vein led to an increased efferent nervous discharge to the intestines. The reflex increase persisted after bilateral vagotomy, after transection of the spinal cord at the level of C7 and after section of the hepatic nerves, but was abolished by section of the intestinal nerves.3. It is suggested that the spinal reflex is concerned with local distribution of blood and that the mesenteric venous ;volume' or ;stretch' receptors which initiate the reflex are similar to those described elsewhere in the body.     

The effect of intracerebroventricular infusions of leptin on the immunoreactivity of neuropeptide Y and gonadotrophin releasing hormone neurons in the hypothalamus of prepubertal sheep in conditions of short fasting

In the study we evaluated the effects of infusion of exogenous leptin to the third ventricle of the brain on the expression of immunoreactive (ir) neuropeptide Y (NPY) neurons in the hypothalamus and ir gonadotrophin releasing hormone (GnRH) nerve terminals in the median eminence of prepubertal lambs in the conditions of short fasting. Merino female sheep (n=16) were randomly divided into four groups, two fed with standard feeds and two fasted for 72 h. One standard and one fasted groups were infused with Ringer saline (controls), remaining standard and fasted groups with leptin (25 microg/120 microl/h), for 4 h during three consecutive days, and then slaughtered. Ir NPY and ir GnRH were localized by immunohistochemistry using specific polyclonal antibodies. Detection of both hormones was followed by the image analysis and expressed as the percent area stained and integral density of immunostaining. In the hypothalami from all groups the ir NPY perikarya and varicose nerve fibers were localized in three distinct sub-areas, in the arcuate (ARC), paraventricular and periventricular nuclei. In fasted sheep the percent area and integral density for immunoreactivity of NPY increased significantly (P<0.001) in three sub-areas compared to the standard-fed animals. Leptin infusion lowered the both parameters (P<0.001) but solely in the ARC NPY population of fasted sheep. The percent area and integral density of immunostaining for ir GnRH in fasted sheep revealed the augmentation (P<0.001) compared to standard-fed sheep. Leptin infusions diminished (P<0.001) both parameters in fasted, without effects in standard-fed lambs. In conclusion, the enhanced by fasting immunoreactivity of the ARC NPY perikarya and varicose nerve fibers and restrained immunoreaction of GnRH terminals in the median eminence were reversed by exogenous leptin. It is suggested that leptin can affect GnRH release via ARC NPY neurons in conditions of deficit of nutrients in prepubertal, female lambs.     

Anatomy and function of sensory hepatic nerves

Vagal and spinal afferent innervation of the portal hepatic area has not been studied as thoroughly as the innervation of other important organs. It is generally agreed that unlike noradrenergic sympathetic efferent nerve fibers, sensory nerve fibers of either vagal or dorsal root/spinal origin do not directly innervate hepatocytes, but are restricted to the stroma surrounding triades of hepatic vasculature and bile ducts, and to extrahepatic portions of the portal vein and bile ducts. For vagal afferent innervation, retrograde and anterograde tracing studies in the rat have clearly shown that only a minor portion of the common hepatic branch innervates the liver area, while the major portion descends in the gastroduodenal branch toward duodenum, pancreas, and pylorus. Hepatic paraganglia, bile ducts, and portal vein receive the densest vagal afferent innervation. Calretinin may be a relatively specific marker for vagal afferent innervation of the portal-hepatic space. Calcitonin gene-related peptide (CGRP) is a specific marker for dorsal root afferents, and CGRP-immunoreactive fibers are mainly present near the intrahepatic vascular bundles and bile ducts, and in the same extrahepatic compartments that contain vagal afferents. Because of the specific anatomical organization of hepatic nerves, selective hepatic denervation, whether selective for the vagal or sympathetic division, or for efferents and afferents, is nearly impossible. Great caution is therefore necessary when interpreting functional outcomes of so-called specific hepatic denervation studies.     

Distribution and possible origins of substance P-containing nerve fibers in the rat liver.

The distribution and possible origins of substance P-containing nerve fibers in the rat liver were investigated by immunohistochemistry and nerve transection. Nerve fibers with substance P-like immunoreactivity formed a more complex network than previously known in the walls of portal vein branches. Substance P-immunoreactive fibers were seen not only in and around the walls of the hepatic artery, but also in close association with the hepatic veins and bile ducts. Transection of the greater splanchnic nerves and/or the vagus nerves indicated that substance P-immunoreactive fibers in the walls of the portal and hepatic veins enter the liver via both nerves, and that those associated with the hepatic artery and bile ducts stem from the greater splanchnic nerves. The widespread distribution of hepatic substance P and its complex innervation pattern within the liver suggest that it is involved in a variety of physiological processes in this organ.     

Afferent discharges from venous pressoreceptors in liver.

Afterent discharges were observed in dissected filaments or single nerve fibers of hepatic nerve in the guinea pig and the rabbit. Increasing the perfusion pressure of the portal vein in isolated liver preparation in the guinea pig caused an increase in afferent discharge rate. Discharge patterns were compatible with those of the slowly adapting type. Increasing the portal venous pressure by means of intravenous injection of Locke's solution into the left jugular vein in the rabbit in vivo caused an increase in afferent discharge rate. Increasing the hepatic arterial pressure was without effect. It is suggested that pressoreceptors are present in or near the venous wall of the portal venous system and that they send information about blood pressure in the portal vein to the central nervous system.     

A study of the accessory hepatic vein to segments VI and VII with a morphological reconsideration of the human liver

Introduction The liver is supplied by the common hepatic artery from the celiac trunk and by the portal vein from the gastrointestine. This double blood supply to the liver by the hepatic artery and the portal vein produced a complicated structure in the liver. For the blood outflow, we can see right, intermediate and left hepatic veins, and irregular veins: the accessory hepatic veins. These veins drain the blood in the liver into the inferior vena cava. In this study, we studied the layout of the accessory hepatic vein draining segments 6 and 7 in the human livers and attempted to reconsider the structure of the liver by the layout of the accessory hepatic vein. Methods Sixty livers were subjected in this study. They were prepared by using forceps to trace the layout of the blood vessels inside the livers. We carefully examined the relation between the layouts of the accessory vein to the segments 6 and 7 and of the portal vein. The confluence patterns of the accessory hepatic vein into the inferior vena cava were also examined to find the character of the vein. The relation between the accessory hepatic vein and standard hepatic veins was also studied. Results We found 2.2 accessory hepatic veins in one liver on average in our study. The vein was always within the area of segments 6 and 7, and did not surpass the boundary. We found at most five accessory hepatic veins in a liver in two cases. The accessory hepatic vein to the segments 6 and 7 always had its stem on the dorsal side to the portal vein. Different from the stem, the periphery of the accessory hepatic vein freely distributed with the peripheral branches of the portal vein. The area distributed by the accessory vein was also always dorsal part within the segments 6 and 7. The vein was small usually, but was big in few cases. When the vein was big, the area became solely drained by the accessory vein, because the standard hepatic veins (right and intermediate hepatic veins) did not reach the area, and we did not find any communication between the accessory vein and the standard veins. As the remaining region in the segments 6 and 7 became smaller, the draining right standard hepatic vein became shorter and smaller. Discussion The region drained by the accessory hepatic vein excluded the standard hepatic veins. Therefore, there are two different draining venous networks in the area of segments 6 and 7 classified by Couinaud. Conclusion The accessory hepatic vein draining segments 6 and 7 distributed somewhere dorsal side in the segments 6 and 7. The area where the accessory vein distributed was the region where standard hepatic veins did not reach. This would suggest that the region drained by the accessory hepatic vein makes an isolated segment in the liver in the segments 6 and 7 by the Couinaud’s Classification. The area might have a unique blood circulation system.     

Large veins in the Atlantic cod (Gadus morhua) and the rainbow trout (Oncorhynchus mykiss) are innervated by neuropeptide-containing nerves

Previous studies have shown that fish veins are reactive to several hormones known to exist in the fish circulation. Besides this humoral control, another possible means of active regulation of venous return is by autonomic nervous control of venous tone. This study therefore investigated the presence of a perivascular innervation of major veins in the Atlantic cod (Gadus morhua) and the rainbow trout (Oncorhynchus mykiss) using immunohistochemical methods. Histological staining was employed to investigate the smooth muscle distribution in the vessel walls. Vasoactive intestinal polypeptide-immunoreactive nerve fibers were found to be widespread in the venous system of G. morhua and O. mykiss, while pituitary adenylate cyclase-activating polypeptide-immunoreactive fibers were demonstrated in the duct of Cuvier of both species. Fibers containing neurokinin A and/or substance P were found in the duct of Cuvier and the posterior cardinal vein of both species and in the hepatic portal vein of O. mykiss. Calcitonin-gene related peptide-immunoreactive fibers were present in the duct of Cuvier of both species and in the hepatic portal vein of O. mykiss. Galanin-immunoreactive fibers were found in the duct of Cuvier in O. mykiss and in the hepatic portal vein of both species. Co-existence of neuropeptides in the perivascular nerve fibers was investigated by double labelling. Vasoactive intestinal polypeptide/pituitary adenylate cyclase-activating polypeptide-immunoreactive fibers were found in both species. Vasoactive intestinal polypeptide/galanin-immunoreactive fibers and vasoactive intestinal polypeptide/calcitoningene related peptide-immunoreactive fibers were found in G. morhua but not in O. mykiss. This study gives further evidence for an active venoregulation by autonomic nerves in teleost fish.     

Adrenomedullin facilitates reinnervation of phenol-injured perivascular nerves in the rat mesenteric resistance artery

Our previous report showed that innervation of calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-containing nerves in rat mesenteric resistance arteries was markedly reduced by topical application of phenol, and that nerve growth factor (NGF) facilitates the reinnervation of both nerves. We also demonstrated that a CGRP superfamily peptide, adrenomedullin, is distributed in perivascular nerves of rat mesenteric resistance arteries. In the present study, we investigated the influence of adrenomedullin on the reinnervation of mesenteric perivascular nerves following topical phenol treatment. Under pentobarbital-Na anesthesia, 8-week-old Wistar rats underwent in vivo topical application of phenol (10% phenol in 90% ethanol) to the superior mesenteric artery proximal to the bifurcation of the abdominal aorta. After the treatment, the animals were subjected to immunohistochemistry of the third branch of small arteries proximal to the intestine and to vascular responsiveness testing on day 7. Topical phenol treatment caused marked reduction of the density of NPY-like immunoreactive (LI)- and CGRP-LI nerve fibers in the arteries. Adrenomedullin (360 or 1000 ng/h) or NGF (250 ng/h), which was administered intraperitoneally for 7 days using an osmotic mini-pump immediately after topical phenol treatment, significantly increased the density of CGRP-LI- and NPY-LI nerve fibers compared with saline. Treatment with adrenomedullin (1000 ng/h) or NGF restored adrenergic nerve-mediated vasoconstriction and CGRP nerve-mediated vasodilation in the perfused mesenteric artery treated topically with phenol. These results suggest that adrenomedullin, like NGF, has a facilitatory effect on the reinnervation of perivascular nerves.     

应用SRY原位杂交技术检测肝脏干细胞移植肝内种植情况

背景：以往干细胞种植后的定植示踪技术有磁探针标记、荧光示踪标记法、慢病毒感染荧光标记法及性别交叉Y染色体原位杂交检测法,各有优缺点。 目的：应用SRY原位杂交技术观察受体来源肝脏干细胞(肝卵圆细胞)在移植肝内的定植情况。 方法：二袖套法建立大鼠原位肝移植模型。供体为雌性DA大鼠,受体为雌性Lewis大鼠,设受体大鼠60只,肝卵圆细胞为Lewis大鼠来源的雄性细胞,移植中供肝种植肝卵圆细胞悬液。应用SRY原位杂交染色技术观察受体来源的雄性肝卵圆细胞在雌性移植肝内的定植情况。 结果与结论：经门静脉和肝动脉注射种植的肝卵圆细胞及其分化细胞主要定植在移植肝内中央静脉及汇管区周围,应用SRY原位杂交染色技术可以有效观察到受体来源肝脏干细胞在移植肝内的定植情况。     

人与猪肝门静脉显微结构成分的比较

目的：比较人与猪肝门静脉壁结构成分的异同，为猪一人异种肝移植提供理论依据。方法：取正常成人与不同月龄猪肝门静脉，常规石蜡包埋、切片，分染弹性纤维、胶原纤维和平滑肌，光镜观察，计算机图像分析系统测量各结构成分的相对含量。结果：随月龄的增长猪肝门静脉胶原纤维的含量逐渐升高，弹性纤维的含量相对稳定，平滑肌的含量在3月龄时最高，C厄值逐渐升高。与人相比，猪肝门静脉壁中胶原纤维和弹性纤维的含量较低，而平滑肌的含量则较高，5、6月龄时的C/E值与人相近。结论：人与猪肝门静脉壁各结构成分的含量存在差异，但从C僵值看，5、6月龄猪肝门静脉的力学特性与人相匹配，较适合用于移植。     

Anatomy of efferent hepatic nerves

The role of neural elements in regulating blood flow through the hepatic sinusoids, solute exchange, and parenchymal function is incompletely understood. This is due in part to limited investigation in only a few species whose hepatic innervation may differ significantly from humans. For example, most experimental studies have used rats and mice having livers with little or no intralobular innervation. In contrast, most other mammals, including humans, have aminergic and peptidergic nerves extending from perivascular plexus in the portal space into the lobule, where they course in Disse's space in close relationship to stellate cells (fat storing cells of Ito) and hepatic parenchymal cells. While these fibers extend throughout the lobule, they predominate in the periportal region. Cholinergic innervation, however, appears to be restricted to structures in the portal space and immediately adjacent hepatic parenchymal cells. Neuropeptides have been colocalized with neurotransmitters in both adrenergic and cholinergic nerves. Neuropeptide Y (NPY) has been colocalized in aminergic nerves supplying all segments of the hepatic-portal venous and the hepatic arterial and biliary systems. Nerve fibers immunoreactive for substance P and somatostatin follow a similar distribution. Intralobular distribution of all of these nerve fibers is species-dependent and similar to that reported for aminergic fibers. Vasoactive intestinal peptide and calcitonin gene-related peptide (CGRP) are reported to coexist in cholinergic and sensory afferent nerves innervating portal veins and hepatic arteries and their branches, but not the other vascular segments or the bile ducts. Nitrergic nerves immunoreactive for neuronal nitric oxide (nNOS) are located in the portal tract where nNOS colocalizes with both NPY- and CGRP-containing fibers. In summary, the liver is innervated by aminergic, cholinergic, peptidergic, and nitrergic nerves. While innervation of structures in the portal tract is relatively similar between species, the extent and distribution of intralobular innervation are highly variable as well as species-dependent and may be inversely related to the density of gap junctions between contiguous hepatic parenchymal cells.     

大鼠心冠状动脉系统神经肽Y年龄变化的免疫组织化学研究

运用免疫组化ＡＢＣ法对不同月龄ＳＤ大鼠心脏冠状动脉及其分支含神经肽Ｙ神经纤维的分布及其衰老变化作了详细观察．结果表明：左、右冠状动脉及其各级分支具有丰富的神经肽Ｙ能神经分布．在冠状动脉主干及其较大分支上，神经纤维较稠密，主要呈环状或网状分布，在血管围周形成较多束、丛、网，并伸入血管壁内形成壁内的神经网络分布．部分神经纤维的游离末梢有穿过血管内膜伸向腔面的迹象．在细小的冠状动脉分支上，神经纤维密度减低，主要沿血管长袖是纵向分布．两侧冠状动脉系统神经肽Ｙ能纤维分布形式及密度没有差别．老龄组动物，左、右冠状动脉及其分支的神经肽Ｙ能纤维密度趋于下降，纤维变细，呈断续状，膨体数量减少，免疫染色变浅、此外，在心内发现了神经肽Ｙ能神经节．     

Large veins in the Atlantic cod (Gadus morhua) and the rainbow trout (Oncorhynchus mykiss) are innervated by neuropeptide-containing nerves

Previous studies have shown that fish veins are reactive to several hormones known to exist in the fish circulation. Besides this humoral control, another possible means of active regulation of venous return is by autonomic nervous control of venous tone. This study therefore investigated the presence of a perivascular innervation of major veins in the Atlantic cod (Gadus morhua) and the rainbow trout (Oncorhynchus mykiss) using immunohistochemical methods. Histological staining was employed to investigate the smooth muscle distribution in the vessel walls. Vasoactive intestinal polypeptide-immunoreactive nerve fibers were found to be widespread in the venous system of G. morhua and O. mykiss, while pituitary adenylate cyclase-activating polypeptide-immunoreactive fibers were demonstrated in the duct of Cuvier of both species. Fibers containing neurokinin A and/or substance P were found in the duct of Cuvier and the posterior cardinal vein of both species and in the hepatic portal vein of O. mykiss. Calcitonin-gene related peptide-immunoreactive fibers were present in the duct of Cuvier of both species and in the hepatic portal vein of O. mykiss. Galanin-immunoreactive fibers were found in the duct of Cuvier in O. mykiss and in the hepatic portal vein of both species. Co-existence of neuropeptides in the perivascular nerve fibers was investigated by double labelling. Vasoactive intestinal polypeptide/pituitary adenylate cyclase-activating polypeptide-immunoreactive fiberswere found in both species. Vasoactive intestinal polypeptide/galanin-immunoreactive fibers and vasoactive intestinal polypeptide/calcitonin-gene related peptide-immunoreactive fibers were found in G. morhua but not in O. mykiss. This study gives further evidence for an active venoregulation by autonomic nerves in teleost fish. Accepted: 5 March 2001     

猪肝门静脉壁组织结构增龄性变化的定量分析

目的　探讨猪肝门静脉壁结构成分的增龄性变化 ,为猪 -人异种肝移植提供理论依据。方法　取正常不同月龄猪肝门静脉 ,HE染色 ,Weigert、Anilineblue及桔黄G分染弹性纤维、胶原纤维和平滑肌 ,光镜观察 ,计算机图像分析系统测量各结构成分的相对含量。结果　猪肝门静脉随月龄的增长胶原纤维的含量逐渐升高 ,弹性纤维的含量相对稳定 ,平滑肌的含量在 3月龄时最高 ,胶原纤维与弹性纤维含量的比值 (C/E)逐渐升高。结论　猪肝门静脉壁各结构成分的相对含量随增龄发生变化 ,在实施猪 -人异种肝移植时应选择与人肝门静脉壁结构成分含量相近的月龄猪作为供体。     

大网膜内植入自体脾组织与原位脾组织的结构比较

目的 :为临床应用自体脾组织植入术提供实验研究资料。方法 :大鼠分为实验组和对照组 ,前者切取 1 /2脾脏去包膜后切成 1mm× 1mm× 1mm大小均匀组织块 ,植入大网膜囊袋内。饲养 6个月后取 2组脾组织制片 ,光镜和电镜定性观察组织结构变化 ,计算机图像分析系统比较血管、红髓、白髓及胶原纤维的面密度 ;免疫组化法结合计算机图像分析测定神经肽 (NPY)阳性神经纤维密度。结果 :神经和边缘窦内皮细胞结构恢复较好 ,血管 ,白髓的面密度值较对照组减少 ,红髓与对照组相当 ,胶原纤维面密度增加。结论 :大网膜内植入的自体脾组织通过再生能恢复脾脏的主要组织结构 ,但不能完全恢复正常。     

门静脉的解剖与变异

目的：利用经动脉性门静脉造影CT重建门静脉、肝静脉三维结构，观察生理状态下的门静脉的解剖与变异。方法：150例病人，导管置入于肠系膜上动脉内，注入造影剂后门静脉期和肝静脉期连续扫描肝脏。三维重建门静脉及肝静脉，分析门静脉的解剖与变异。结果：150次成像中门静脉变异25例，12例（8．0％）显示门静脉呈三分叉状，10例（6，7％）门静脉先分出右后支，然后上行分为左支和右前支，1例（0．7％）门静脉左支水平段缺如，门静脉右支缺如2例（1．3％），余下125例（83．3％）显示正常左右门静脉分支。结论：门静脉的三维图像重建及类型分析对术前手术方式的确定有一定的临床意义。     

肝纤维化门静脉压力改变与血清ET-1/NO关系的实验研究

目的制作兔肝纤维化模型，观察血管活性物质与门静脉压力变化的关系。方法40只家兔采用口服硫代乙酰胺方法造模，分别于造模第8、12、16、20周时检测内皮素（ET-1）及NO浓度，超声观察胆囊壁及肝脏血流动力学指标，直接穿刺测量不同时期门静脉压力。分析血管活性物质与肝脏血流动力学指标及门静脉压力变化间的关系。结果胆囊壁增厚是肝纤维化阶段的二维超声表现；随着纤维化程度的加重，血清ET-1、NO浓度逐渐增加，且以ET-1／N0比值增加更为明显；门静脉内压力、肠系膜上动脉、脾动脉搏动指数（PI）随纤维化程度逐渐增加，实验组与对照组间差异有统计学意义（P〈0．05），且与ET-1／NO值呈正相关（P〈0．01）。结论通过超声可无创检测肝脏血流动力学变化，对肝纤维化临床诊断及治疗效果的观察，具有积极的作用。     

Secondary joining of the bile ducts during the hepatogenesis of the mouse embryo

Summary Development of the bile duct system of the mouse embryo was studied histologically and by an immunofluorescent technique. The hepatic primordium consisted of cranial and caudal portions. In the liver of young embryos, the hepatic cords were present in the presumptive cysticduct epithelium, and the histology of the presumptive cystic duct epithelium near the hilus was similar to that of the hilus epithelium. The results suggest that at least a part of the cystic duct epithelium develops from the cranial diverticulum of the hepatic primordium. Lumen structures were precursors of intrahepatic bile ducts and originated from type I (immature) hepatocytes. The lumina of the lumen structures appeared near the hilus area first, but most were discontinuous with those of the hepatic ducts. With the progress of development, the discontinuous lumen structures became distributed around the portal vein branches in the central part of the liver parenchyma, and gradually connected with each other and also with hepatic ducts. the discontinuous laminin immunofluorescence also appeared in the endodermal cells around the portal vein branches at the younger stages. Therefore, it is conceivable that the intrahepatic bile ducts originate from discrete cell populations of type I hepatocytes around the portal vein branches and subsequently become confluent, but not from the cells of hepatic ducts.     

Anatomical distribution of NPY‐like immunoreactivity in the domestic chick brain (Gallus domesticus)

Neuropeptide Y‐immunoreactive (NPY‐ir) fibers and neurons in the brain of the domestic chick (Gallus domesticus) were described using an immunohistochemical technique. NPY‐ir neurons were seen in the lobus parolfactorius; hyperstriatum, neostriatum, paleostriatum, and archistriatum; hippocampal and parahippocampal areas; dorsolateral corticoid area; piriform cortex; two thalamic areas contiguous to the n. rotundus; n. dorsolateralis anterior thalami, pars lateralis, and pars magnocellularis; n. periventricularis hypothalami; n. paraventricularis magnocellularis; regio lateralis hypothalami; n. infundibuli; inner zone of the median eminence; dorsal and lateral portions of the n. opticus basalis; n. raphes; and n. reticularis paramedianus. NPY‐ir fibers were seen throughout the entire chick brain, but were more abundant in the hypothalamus where they formed networks and pathways. They were also observed in some circumventricular organs. The anatomical data of the present study regarding the distribution of NPY ir in the chick brain, together with the physiological findings of other studies, suggest that NPY plays a key role in the regulation of the neuroendocrine, vegetative, and sensory systems of birds by acting as a neuromodulator and/or neurotransmitter. Anat Rec 263:186–201, 2001. © 2001 Wiley‐Liss, Inc.