The distribution of histamine and serotonin in the barnacle's nervous system

The use of antisera directed against conjugates of histamine and serotonin has revealed the locations of neurons labeling for these transmitters in the nervous system of barnacles. Photoreceptors label for histamine but not serotonin and also satisfy a number of other criteria indicating that histamine is their neurotransmitter. Photoreceptors also take up radioactively labeled histamine but not serotonin. Within the barnacle's brain no somata are consistently found that label with antiserum against histamine, but one to three pairs of small cells, depending on species, label with antiserum against serotonin. The most impressive serotonin-like immunoreactivity in the brain, however, is in a pair of large fibers ascending through the circumesophageal connectives and ramifying extensively. Within the ventral ganglion, the only other ganglion in the barnacle, ten pairs of cells label with antiserum against histamine. These neurons are confined to the posterior portion of the ganglion but ramify extensively throughout the ganglion. Antiserum against serotonin labels about 15 cell pairs, depending on species, located throughout the ganglion. The positions of the arbors of many of these cells suggest that these amines have a role in modulating either the motor pathways underlying feeding or the visual pathways responsible for the detection of shadows.     

Neuronal classification and distribution in the central nervous system of the female mud crab,Scylla olivacea

The mud crab, Scylla olivacea, is one of the most economically valuable marine species in Southeast Asian countries. However, commercial cultivation is disadvantaged by reduced reproductive capacity in captivity. Therefore, an understanding of the general and detailed anatomy of central nervous system (CNS) is required before investigating the distribution and functions of neurotransmitters, neurohormones, and other biomolecules, involved with reproduction. We found that the anatomical structure of the brain is similar to other crabs. However, the ventral nerve cord (VNC) is unlike other caridian and dendrobrachiate decapods, as the subesophageal (SEG), thoracic and abdominal ganglia are fused, due to the reduction of abdominal segments and the tail. Neurons in clusters within the CNS varied in sizes, and we found that there were five distinct size classes (i.e., very small globuli, small, medium, large, and giant). Clusters in the brain and SEG contained mainly very small globuli and small‐sized neurons, whereas, the VNC contained small‐, medium‐, large‐, and giant‐sized neurons. We postulate that the different sized neurons are involved in different functions. Microsc. Res. Tech. 77:189–200, 2014. © 2013 Wiley Periodicals, Inc.     

Biogenic amines in the brain of the honeybee: cellular distribution, development, and behavioral functions

This review provides a summary of the cellular distribution of amine-containing neurons and the organization of aminergic pathways in the brain and suboesophageal ganglion of the honeybee. Neurons synthesizing the biogenic amines serotonin, dopamine, octopamine, and histamine are stained with well-defined polyclonal antisera. Since some of these aminergic neurons are uniquely identifiable, it is possible to follow their morphogenesis during brain development. Pharmacological studies show that aminergic mechanisms are involved in various behavioral modifications including associative learning. The immunocytochemical approach resolves at a single cell level the neural pathways that mediate adaptive behavioral changes.     

Role of the central and peripheral nervous system in the ovarian function

This review attempts to give a comprehensive overview of ovarian innervation, considering the whole nervous system and its different levels that may modify the ovarian function. The connection between the ovary and the central nervous system through the autonomic pathways, including the peripheral ganglia, is highlighted. The evidence obtained over the last years highlights the role of the superior ovarian nerve (SON) in the ovarian phenomena. Besides, the effect on the ovary of conventional neurotransmitters and others such as indolamines and peptides, which have been found in this organ, are discussed. Various reproductive diseases have been studied almost exclusively from the endocrine point of view. It is evident that a better knowledge about the role of the neural factors involved in the ovarian physiology may facilitate the understanding of some of these. A review of the concepts and an update of some experimental designs is made that permits clarifying several aspects of the relationship between the neural system and the ovary. At present, there is no doubt that the innervation of the ovary is involved in several physiological aspects of this gland function. However, the relationship of some levels of the nervous system and the ovary offer a wide avenue for future research.     

Distribution and regulation of substance P-related peptide in the frog visual system

Modulation of visual signal activity has consequences for both signal processing and for activity-dependent structuring mechanisms. Among the neuromodulatory agents found in visual areas are substance P (SP)-related peptides. This article reviews what is known about these substances in the amphibian retina and optic tectum with special emphasis on the leopard frog, Rana pipiens. It is found that the distribution of these SP-related peptides is remarkably similar to that seen in mammals. This suggests that study of model amphibian systems may significantly enhance our understanding of how neuropeptides contribute to visual system function and organization.     

变电站微机防误的可视化系统设计与实现

近几年来,随着变电站增多与规模不断扩大,很多变电站实现了无人值班,导致集控中心无法对变电站进行全面掌控,以及不能实施场地与环境监视等方面问题。由此设计了一款以可视化监控为核心技术的变电站微机防误系统,该系统采用了智能化监控技术,对原变电站与其接口进行重点优化,同时还对各个子系统之间采用了无缝接入,进行统一配置与管理,从而实现了可视化控制目标。最后通过研究表明此款新系统能够很好解决变电站现场管理与维护等方面问题,使得它的社会效益得到提升,在变电机管理领域具有广阔的应用前景。     

Influence of friction on the prediction of forces, pressure distributions and properties in upset forging

The axial compression of solid cylinders with initially equal height and diameter between flat parallel platens is examined.

A finite-element method is used to predict the platen forces, the pressure distribution, and the strain and hardness distributions within the billet, for various levels of interface shear stress.

The theoretical predictions of pressure distribution indicate that a simple friction-hill does not occur for this billet shape; a number of different distributions are found, dependent on the boundary conditions.

Two distinct modes of flow are identified, again dependent on the boundary conditions.

Experiments with commercially pure aluminium cylinders show good correlation with the predictions for unlubricated aluminium and for aluminium lubricated by a thin film of lead.     

Eliminating instability due to nonconservative hydrodynamic forces in the system consisting of a flexible rotor and a sealing ring

The stability of a moving transcritical rotor with a sealing ring, under the action of hydrodynamic forces in the annular gap between the rotor and ring, is analyzed. The conditions corresponding to stability loss are discussed.     

Intensity, slope and curvature discontinuities in loading distributions at the contact of two plane bodies

The optical method of caustics was used for the evaluation of intensity, slope and curvature discontinuities of the most general load distribution along a straight boundary in a semi-infinite plane simulating the elastic contact of two bodies under conditions of generalized plane stress. The load distribution was assumed as composed of normal as well as tangential loads.A simple procedure based on the geometric properties of caustics formed at the vicinity of such discontinuities in loading was developed, which yielded all the necessary information for the evaluation of such discontinuities. Interesting properties related to the shape, position and orientation of the caustics were established. Thus, a simple experimental procedure was developed for measuring the influence of friction along the contact area of two bodies.     

Localization and identification of crustacean hyperglycemic hormone producing neurosecretory cells in the eyestalk of blue swimmer crab,Portunus pelagicus

This study intensely focuses on to the localization and identification of crustacean hyperglycemic hormone (CHH) producing neurosecretory cells in the eyestalk of the blue swimmer crab Portunus pelagicus. Anti‐Carcinus maenas‐CHH was used to identify the location of CHH neurosecretory cells by immunohistochemistry. Ten pairs of eyestalks were collected from intact adult intermoult female crab and fixed in Bouin's fixative. Eyestalks were serially sectioned and stained with chrome‐hematoxylin‐phloxine stain. Histological studies show the presence of different types of neurosecretory cells namely A (multipolar), B (tripolar), C (bipolar), D (unipolar), E (oval), and F (spherical) in the medulla interna, externa, and terminalis regions based on their size, shape, and tinctorial properties. The neurohemal organ, sinus gland (SG) was observed laterally between medulla interna and terminalis regions. Immunohistochemical studies showed the presence of distinct CHH‐like immunoreactivity in the optic ganglia. Divergent group of neurosecretory cells with varying degree of immunoreactivity with Anti‐Carcinus maenas‐CHH (low, moderate, and intense reactivity) were identified in medulla terminalis, medulla interna, medulla externa, and sinus gland. The present study maps the various types of neurosecretory cells in the optic ganglia and also shows the presence of CHH‐like immunoreactivity in various regions of optic ganglia in P. pelagicus. The presence of these unique neurosecretory cell types with larger cell diameter in medulla terminalis, a region that bears the neurosecretory cell bodies, suggest high secretory activity.     

Changes in central steroid receptor expression, steroid synthesis, and dopaminergic activity related to the reproductive cycle of the ring dove

This review examines possible neural mechanisms involved in the expression of parental behavior in the ring dove, Streptopelia risoria. This avian species has proved an excellent animal model for studies concerning endocrine-behavior interactions for many years. Studies were performed to localize the expression of central androgen and progesterone receptor in both sexes. Expression of androgen receptor (androgen receptor immunoreactivity, AR-ir) was widespread but increased, similarly in both sexes, with increasing day-length. Progesterone receptor-immunoreactivity (PR-ir) was more localized in several discrete areas of the hypothalamus. Similarly, no sex differences were observed in PR-ir, and expression increased in birds maintained on long days. AR-ir demonstrated dramatic changes over the breeding cycle, being greatest in courting birds and almost undetectable in parenting birds of both sexes brooding their young. PR-ir showed a differential expression over the breeding cycle relative to its hypothalamic localization. PR-ir decreased in the tuberal hypothalamic area in brooding birds of both sexes; whereas in the preoptic area, PR-ir was maintained. Significant increases in dopaminergic activity during the parenting phase of the breeding cycle occurred in specific neural regions including the PVM and DMA. Studies demonstrated the ability of the diencephalon of both sexes of the ring dove brain to synthesize progesterone, with indications that in the male brooding dove, synthesis is increased. Finally, a model is presented that proposes a mechanism whereby these central systems may interact to result in the expression of full parental behavior in both sexes of the ring dove.     

Ultrastructural and paraphenylene studies of degeneration in the primate visual system: Degenerative remnants persist for much longer than expected

It is a widely held belief that the products of axonal degeneration in the CNS are transitory and are caused by metabolic and phagocytic processes. However, recent light microscopic examinations of human and primate brains using the paraphenylene diamine staining method (PPD), which stains degenerating axons, have confirmed that the products of degeneration persist for years in visual pathways. The routine utilization of the PPD method for delineating human visual pathways requires further confirmation of axonal degeneration. Optic nerves, optic tracts, and lateral geniculate nuclei were collected from human brains that had clinical documentation of optic nerve damage prior to death. Optic nerves, optic tracts, and lateral geniculate nuclei taken from the brains of cynomolgus monkeys that had undergone enucleation 3 months to 1 year prior to sacrifice were also examined. All tissue was processed for electron microscopy; ultrathin sections were cut for electron microscopy, and consecutive sections were cut for light microscopy. In all cases, the homology of the degenerated processes was confirmed between the light microscopic (PPD) and the electron microscopic sections. Such ultrastructural examination demonstrates that the products of axonal degeneration remain in the primate visual system longer than previously supposed.     

Expression of the male reproduction‐related gene in spermatic ducts of the blue swimming crab,Portunus pelagicus,and transfer of modified protein to the sperm acrosome

Expression of a sex‐specific gene in Macrobrachium rosenbergii (Mr‐Mrr), encoding a male reproduction‐related (Mrr) protein, has been identified in the spermatic ducts (SDs) and postulated to be involved in sperm maturation processes. M. rosenbergii is the only decapod that the expression and fate of the Mrr protein has been studied. To determine that this protein was conserved in decapods, we firstly used cloning techniques to identify the Mrr gene in two crabs, Portunus pelagicus (Pp‐Mrr) and Scylla serrata (Ss‐Mrr). We then investigated expression of Pp‐Mrr by in situ hybridization, and immunolocalization, as well as phosphorylation and glycosylation modifications, and the fate of the protein in the male reproductive tract. Pp‐Mrr was shown to have 632 nucleotides, and a deduced protein of 110 amino acids, with an unmodified molecular weight of 11.79 kDa and a mature protein with molecular weight of 9.16 kDa. In situ hybridization showed that Pp‐Mrr is expressed in the epithelium of the proximal, middle, distal SDs, and ejaculatory ducts. In Western blotting, proteins of 10.9 and 17.2 kDa from SDs were all positive using anti‐Mrr, antiphosphoserine/threonine, and antiphosphotyrosine. PAS staining showed they were also glycosylated. Immunolocalization studies showed Pp‐Mrr in the SD epithelium, lumen, and on the acrosomes of spermatozoa. Immunofluorescence staining indicated the acrosome of spermatozoa contained the Mrr protein, which is phosphorylated with serine/threonine and tyrosine, and also glycosylated. The Mrr is likely to be involved in acrosomal activation during fertilization of eggs. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.     

Impact of descending brain neurons on the control of stridulation, walking, and flight in orthoptera

Orthopteran insects (crickets, bushcrickets, and acridid grasshoppers) are preferred preparations for the study of the central nervous mechanisms that underlie behavior. Many of their behaviors are based on central rhythm-generating circuits located in the ganglia of the ventral nerve cord. Activities of these circuits must be coordinated and adapted to the behavioral context by sensory information, which can derive from proprioceptive or exteroceptive inputs. Information from various sensory modalities converges in yet unidentified "higher brain centers" that integrate and transform it into activity patterns across populations of descending brain neurons (DBNs). Transmission of "decisions" to the thoracic motor centers leads to adjustment of their functions in order to fit the sensory situation encountered. A number of unique DBNs has been identified by morphological and physiological criteria and their role in controlling aspects of specific behaviors has been the subject of various studies. Their functions range from "switch-like" transmitters of brain output to complex integration units for sensory inputs of various modalities and their appropriate insertion into the ongoing activities of the thoracic rhythm generators. This paper highlights some of the characteristics of DBNs by focussing on three motor behaviors: stridulation, a stereotyped behavior that seems to be mainly controlled by command-like DBNs; walking, a plastic behavior whose various parameters must continuously be adjusted to a changing sensory environment; and flight, in which the information for course corrections encoded for by different types of DBNs is transformed to match the rhythmic activity of the flight oscillators before it affects the respective motoneurons.     

Elemental changes in the brain, muscle, and gut cells of the housefly, Musca domestica, exposed to heavy metals

The toxic effects of heavy metals on organisms are well established. However, their specific action at the cellular level in different tissues is mostly unknown. We have used the housefly, Musca domestica, as a model organism to study the toxicity of four heavy metals: copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb). These have been fed to larvae at low and high, semi-lethal concentrations, and their accumulation in the head, thorax, and abdomen was subsequently measured in adult flies. In addition, their impact on the cellular concentration of several elements important for cell metabolism-sodium (Na+), magnesium (Mg++), phosphorous (P), sulphur (S), chloride (Cl-) and potassium (K+)-were measured in neural cells, muscle fibers, and midgut epithelial cells. Our study showed that the heavy metals accumulate mainly in the abdomen, in which the concentrations of two of the xenobiotic metals, Cd and Pb, were 213 and 23 times more concentrated, respectively, than in controls. All the heavy metals affected the cellular concentration of light elements in all cell types, but the changes observed were dependent on tissue type and were specific for each heavy metal, and its concentration.     

Synaptic structure, distribution, and circuitry in the central nervous system of the locust and related insects.

The Orthopteran central nervous system has proved a fertile substrate for combined morphological and physiological studies of identified neurons. Electron microscopy reveals two major types of synaptic contacts between nerve fibres: chemical synapses (which predominate) and electrotonic (gap) junctions. The chemical synapses are characterized by a structural asymmetry between the pre- and postsynaptic electron dense paramembranous structures. The postsynaptic paramembranous density defines the extent of a synaptic contact that varies according to synaptic type and location in single identified neurons. Synaptic bars are the most prominent presynaptic element at both monadic and dyadic (divergent) synapses. These are associated with small electron lucent synaptic vesicles in neurons that are cholinergic or glutamatergic (round vesicles) or GABAergic (pleomorphic vesicles). Dense core vesicles of different sizes are indicative of the presence of peptide or amine transmitters. Synapses are mostly found on small-diameter neuropilar branches and the number of synaptic contacts constituting a single physiological synapse ranges from a few tens to several thousand depending on the neurones involved. Some principles of synaptic circuitry can be deduced from the analysis of highly ordered brain neuropiles. With the light microscope, synaptic location can be inferred from the distribution of the presynaptic protein synapsin I. In the ventral nerve cord, identified neurons that are components of circuits subserving known behaviours, have been studied using electrophysiology in combination with light and electron microscopy and immunocytochemistry of neuroactive compounds. This has allowed the synaptic distribution of the major classes of neurone in the ventral nerve cord to be analysed within a functional context.     

Distribution of dopamine receptors and dopamine receptor homologs in the brain of the honey bee, Apis mellifera L

In the brain of the honey bee, Apis mellifera, the radioligands [3H]-SCH23390 and [3H]-spiperone recognise D1- and D2-like receptors, respectively. In addition to being pharmacologically distinct and exhibiting significantly different expression profiles during the lifetime of the bee, [3H]-SCH23390- and [3H]-spiperone-binding sites differ markedly in their distribution within the brain. Estimates of [3H]-SCH23390-binding site density are highest in the somatal rind, whereas [3H]-spiperone-binding sites are most concentrated in the beta lobe neuropil of the mushroom bodies. Molecular cloning techniques have been used to identify two honey bee genes encoding dopamine receptor homologs. The first is the honey bee counterpart of a Drosophila D1-like dopamine receptor and is expressed in the mushroom bodies of both workers and drones. The second is related to D2-like dopamine receptors from vertebrates and is expressed in the brain of the bee, but the precise distribution of expression is not yet known.     

Histological and immunocytochemical localization of serotonin-like immunoreactivity in the brain and optic ganglia of the Indian white shrimp, Fenneropenaeus indicus

Serotonin is one of the important neurotransmitter and neuromodulator so far studied in crustacean models. With its secretory sites well-studied in higher crustaceans, its function in controlling the release of metabolic hormones from their storage and release sites has been well proved. The present study attempts to localize serotonin-like immunoreactivity in Fenneropenaeus indicus, a commercially important shrimp species and a natural inhabitant of the Indian oceans. Histological studies were employed to visualize the different types of neurosecretory cells and their regions of occurrence in brain and optic ganglia on the basis of their size, shape, and tinctorial properties. Immunocytochemical studies were performed in the brain and optic ganglia with specific antisera against serotonin in combination with peroxidase anti-peroxidase to map the serotonin-like immunoreactive cells. Variations in the immunoreactivity were observed on comparing the cells of brain and optic ganglia. Medulla terminalis region had intense serotonin immunoreactivity suggesting it to be the primary source of the neurotransmitter.