Evidence that naloxone attenuates the consumption of food by domestic pigeons through a central influence

Three experiments were performed on domestic pigeons deprived of food for 24 hr to determine whether the anorexic influence of naloxone, which is observed in this species, results from a central effect of this drug. Injections were given 15 min before the delivery of food, and repeated measures of the consumption of food were obtained during the next 20 min. The systemic administration of either 2 or 10 mumol of naloxone, but not of equimolar amounts of quaternary naloxone, that does not traverse the blood-brain barrier, reduced the consumption of food of the pigeons. At a dose of 20 mumol, quaternary naloxone also slightly attenuated the ingestion of food, possibly because this drug can penetrate the blood-brain barrier when given in large doses. In another experiment, the intraventricular administration of 12.5, 25, 50, or 100 micrograms of naloxone attenuated the food intake in a dose-related fashion. Injection of 25 micrograms of the antagonist was more efficient in this respect when administered intraventricularly rather than systemically. From these experiments, it is concluded that in pigeons, the anorexic influence of naloxone is, at least partly, centrally mediated.     

Kainate-induced lesion in the optic tectum: dependency upon optic nerve afferents or glutamate

Kainic acid is known to induce characteristic lesions in neurons receiving an intact input with presumed glutamate-mediated neurotransmission. There are indications for glutamate as a transmitter of retinal afferent terminals in the pigeon optic tectum. After tectal injection of kainic acid (0.5–2.0 μg in 0.5 μl) the optic tectum was studied by light and electron microscopy and the following changes were observed: (a) within 1–48 h important neuropil vacuolization predominantly in lower part of layer 5. Such vacuoles were sometimes postsynaptic to identified retinal afferent terminals: (b) within 1 h to 21 days progressive neuronal cell loss throughout the tectal layers. These toxic effects were not observed 2–12 weeks after contralateral retinal ablation but could partially be restored by combined glutamate (0.2 mg) and kainate injection. Thus in the pigeon tectum, kainic acid neurotoxicity is dependent upon an intact retinal input, a finding consistent with a special role for glutamate — possibly as a transmitter — in retinal terminals.     

Early colour deprivation in the pigeon

When cats and monkeys are deprived of specific stimuli during an early sensitive period the development of their visual system is known to be affected. In pigeons, pattern discrimination learning has been shown to be affected by monocular deprivation [2]. Our study was set up to examine whether colour discrimination learning could be affected by colour deprivation. Young pigeons were reared under restricted colour illumination for at least 3 months after hatching so as to obtain a group bred under red illumination, one bred under blue illumination and a control group. After this period several psychophysical tests were used to test the pigeons' sense of colour. No significant difference was found between the ‘deprived’ birds and the controls. The spectral sensitivity, determined with the help of the ERG, did not differ for the three groups. We conclude that early colour deprivation does not affect visual development in the pigeon.     

A quantitative approach to cytoarchitectonics

Summary A map of the areal pattern of the hyperstriatum ventrale in the domestic pigeon (Columba livia f.d.) is proposed. This map is based mainly on the distribution of the grey level index which has been characterized using an automatic image analyzer. Twelve areas are described. They are classified into two groups (Hvm 1–6, Hvl 1–6) which are defined by a different range of grey level indices. Three of these areas show topographic relationships to primary projection areas in the neighbouring neostriatum (Nucleus basalis, Ectostriatum, Feld L), and connections are in part well known. Therefore, these areas are assumed to be associative in function. The function of the other areas remains an open question.Supported by Deutsche Forschungsgemeinschaft (SFB 114, Zi 192/4-4)Dedicated to Dr. H. Stephan, Frankfurt/Main, on the occasion of his 60th birthday     

Molecular characterization of a Class I Newcastle disease virus strain isolated from a pigeon in China

Constant monitoring is performed to elucidate the role of natural hosts in the ecology of Newcastle disease virus (NDV). In this study, an NDV strain isolated from an asymptomatic pigeon was sequenced and analysed. Results showed that the full-length genomes of this isolate were 15,198 nucleotides with the gene order of 3′-NP-P-M-F-HN-L-5′. This NDV isolate was lentogenic, with an intracerebral pathogenicity index of 0.00 and a mean time of death more than 148?h. The isolate possessed a motif of -¹¹²E-R-Q-E-R-L¹¹⁷- at the F protein cleavage site. In addition, 7 and 13 amino acid substitutions were identified in the functional domains of fusion protein (F) and haemagglutinin-neuraminidase protein (HN) proteins, respectively. Analysis of the amino acids of neutralizing epitopes of F and HN proteins showed 3 and 10 amino acid substitutions, respectively, in the isolate. Phylogenetic analysis classified the isolate into genotype Ib in Class I. This isolate shared high homologies with the NDV strains isolated from wild birds and waterfowl in southern and eastern parts of China from 2005 to 2013. To our knowledge, this study is the first to report a NDV strain isolated from pigeon that belongs to genotype Ib in Class I, rather than to the traditional genotype VI or other sub-genotypes in Class II. This study provides information to elucidate the distribution and evolution of Class I viruses for further NDV prevention.     

Pigeon fanciers' lung: identification of disease-associated carbohydrate epitopes on pigeon intestinal mucin.

Pigeon intestinal mucin, a complex high molecular weight glycoprotein, is a key antigen in the development of pigeon fanciers' lung (PFL). We have studied the specificity of antibodies to mucin in patients with PFL and asymptomatic antibody-positive individuals. Extensive papain digestion, which removes the non-glycosylated regions of the mucin leaving the heavily glycosylated 'bottle brush' regions, resulted in a 600-fold decrease in IgG3 antibody titres with little effect on IgG1 and IgG2 titres. This suggests that IgG1 and IgG2 are directed against the region rich in O-linked sugar chains whilst the majority of the IgG3 is directed against epitopes which are proteinase-sensitive. Lectin mapping of the carbohydrates present on pigeon intestinal mucin demonstrated high levels of exposed N-acetyl neuraminic acid, N-acetyl galactosamine and N-acetyl glucosamine, with lower levels of fucose and some galactose. Sera from pigeon fanciers inhibited binding of lectins specific for N-acetyl neuraminic acid, N-acetyl galactosamine, internal N-acetyl glucosamine and fucose. Sera from people with PFL, compared with sera from asymptomatic antibody-positive fanciers, had significantly higher titres of antibody that inhibited binding of four lectins specific for N-acetyl galactosamine and one fucose-specific lectin, suggesting that these sugars may play a dominant role in disease-associated epitopes. The results suggest that different IgG subclasses recognize different epitopes on mucin and that the epitopes recognized by the major subclasses are present on the O-linked oligosaccharides. Further, the carbohydrate-specific anti-mucin antibodies produced by PFL patients may differ in their specificity from those found in asymptomatic individuals.     

儿童特发性足内偏步态的病因、评估和治疗

足内偏步态是困扰家长和儿科医生常见问题,大多数是特发性的,无明确病因,也可能是潜在性疾病的表现。大部分的症状和异常可随儿童发育及步态成熟自行纠正,仍有少数不能自行纠正,并可能继发更严重的畸形。其治疗由年龄、具体原因、结构或功能严重程度决定。回顾国内外儿童特发性足内偏步态的病因、评估和治疗,使家长和医生能正确理解和看待足内偏步态,选择适合的治疗方法和时机。     

维吾尔族饲鸽者肺血清总IgE及蛋白电泳分析

目的了解维吾尔族饲鸽者肺患者血清总Ig E、蛋白电泳谱的情况及临床意义。方法病例分析新疆省人民医院确诊的20例维吾尔族饲鸽者肺患者和同期20例维吾尔族健康体检者血清总Ig E及蛋白电泳谱情况。结果两组比较血清总Ig E差异无统计学意义(P0.05);维吾尔族饲鸽者肺患者血清蛋白电泳特征为白蛋白比例减少,γ球蛋白比例增高,与对照组比较差异有统计学意义(P0.05)。结论血清总Ig E及蛋白电泳检测对维吾尔族饲鸽者肺病临床诊断,可提供一定的参考价值。