The morphology of neurosecretory neurones in the pond snail, Lymnaea stagnalis , by the injection of Procion Yellow and horseradish peroxidase

1980 ◽  
Vol 290 (1042) ◽  
pp. 449-478 ◽  
Keyword(s):  
Lymnaea Stagnalis ◽  
Cerebral Ganglion ◽  
Pedal Ganglion ◽  
Axonal Projections ◽  
Procion Yellow ◽  
The Central Nervous System ◽  
Dark Green ◽  
Connective Tissue Sheath ◽  
Pleural Ganglion ◽  
Light Green

The morphology of neurosecretory neurones, the Dark Green Cells, Yellow Cells, Yellow-green Cells, Light Green Cells, Caudodorsal Cells and Canopy Cells, in the central nervous system of the snail, Lymnaea stagnalis , was investigated by the intracellular injection of Procion Yellow and, for the Yellow Cells only, of horseradish peroxidase. The cerebral ganglia neurosecretory cells (Light Green Cells, Caudodorsal Cells and Canopy Cells) had discrete neurohaemal organs and their axons projected exclusively to nerves and connectives close to the central nervous system. The Light Green Cells had single, undividing axons, which projected exclusively to the ipsilateral median lip nerve. Hormone release is thought to take place principally from the lateral edges of axons, at various points along their lengths, within the median lip nerve. The Caudodorsal Cells projected to the cerebral commissure, where their axons often branched before terminating at the edge of the neuropil. The degree of axonal branching and the location of the Caudodorsal Cell terminals varied widely in different cells. Axon terminals penetrated the perineurium and travelled for several hundred micrometres within the connective tissue sheath of the cerebral commissure. Again, release of neurosecretory material at various points along their lengths seems likely. The Canopy Cells (a pair of individually identifiable giant cells) had a single axon, which projected to the contralateral cerebral ganglion via the cerebral commissure. Axons of left and right Canopy Cells were closely apposed in the cerebral commissure and this is the likely site of the electrotonic junction known to connect them. Neurohaemal organs for the Caudodorsal Cells are the ipsilateral lateral lobe, cerebral commissure and contralateral median lip nerve. Neurosecretory neurones whose cell bodies were located in the pleural, parietal and visceral ganglia (Yellow Cells, Yellow-green Cells and Dark Green Cells) had extensive non-localized neurohaemal areas in the connective tissue sheath surrounding the central ganglia as well as peripheral nerve projections. The Yellow Cells had one or two axons, which, in neurones located in the visceral and right parietal ganglia, projected extraganglionically to the central sheath or to the intestinal and internal right parietal nerves. These nerve projections are appropriate for the innervation of the kidney, the peripheral target organ of the Yellow Cells. Yellow Cells, located in the pleural ganglia, only had axonal projections to the central sheath. Yellow Cells and Yellow-green Cells had well developed dendritic branching terminating in the central neuropil. Yellow-green Cells project mainly to the anal and external right parietal nerves. Pleural ganglia Dark Green Cells had a few terminals located beneath the perineurium of the pleural ganglia but most of their axonal projections were to peripheral nerves. All Dark Green Cells projected to the ipsilateral pedal ganglion and then to pedal nerves. In addition, some pleural Dark Green Cells had further projections to the internal and external right parietal nerves and median lip nerve of the cerebral ganglion. The widespread distribution of Dark Green Cell axons was consistent with their supposed role in regulating ion and water transport across the skin of the foot and mantle. The electrotonic junctions known to connect Dark Green Cells whose cell bodies are close together on the pleural ganglion surface are located in the pleural ganglion, pleuro-pedal connective and pedal ganglion.

The anatomy of neurosecretory neurones in the pond snail Lymnaea stagnalis (L)

1976 ◽  
Vol 274 (931) ◽  
pp. 169-202 ◽  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Lymnaea Stagnalis ◽  
Cell Types ◽  
Dark Field ◽  
Neurosecretory Cells ◽  
Pond Snail ◽  
Green Cell ◽  
The Central Nervous System ◽  
Dark Green

The anatomy of three neurosecretory cell types in the central nervous system (c.n.s.) of the gastropod mollusc Lymnaea stagnalis (L.) - the Dark Green Cells, Yellow Cells and Yellow-green Cells - has been studied by using bright and dark field illumination of material stained for neurosecretion by the Alcian Blue-Alcian Yellow technique. The neuronal geometry of single and groups of neurosecretory cells of the various types has been reconstructed from serial sections, and the likely destination of most of their processes has been determined. Dark Green Cells are monopolar, occur exclusively within the central nervous system (c.n.s.), have few or no branches terminating in neuropile, and send axons to the surface of the pleuro-parietal and pleuro-cerebral connectives. The majority of Dark Green Cell axons however (80- 85%), project down nerves which innervate ventral and anterior parts of the head-foot, the neck and the mantle. Dark Green Cell axons can be found in small nerves throughout these areas, and may terminate in a fine plexus of axons on the surfaces of the nerves. Since previous experimental work has shown that the Dark Green Cells are involved in osmotic or ionic regulation, these results suggest that the target organ of the Dark Green Cells may be the skin. Yellow Cells occur both within and outside the c.n.s. They are usually monopolar, but can be bipolar. They have several axons which normally arise separately from a single pole of the cell body, or close to it. One or more processes leave the cell proximal to the point where separate axons arise, and may run unbranched for some distance through neuropile before terminating in fine branches and blobs of various sizes. These branches may release hormone inside the c.n.s. Yellow-green Cells are mono-, bi- or multi-polar, and like the Yellow Cells are found both within and outside the c.n.s. Some Yellow-green Cells, though not all, have projections which terminate in neuropile in fine branches and blobs. Yellowgreen Cell bodies which occur in nerves can project back along the nerve into the c.n.s. The axons of Yellow Cells and Yellow-green Cells project to release sites in various ways. Some project into the connective tissue sheath of the c.n.s., which serves as a neurohaemal organ, either directly through the surface of a ganglion, or from the pleuro-cerebral or pleuro-parietal connectives. Other axons leave the c.n.s. via nerves leaving the left and right parietal and visceral ganglia; projections into the intestinal, anal, and internal right parietal nerves being most numerous. Axons which may be from either, or both Yellow Cells and Yellow-green Cells, can be found along the entire unbranched lengths of these nerves, and in subsequent branches which innervate organs lying in the anterior turn of the shell. All of these organs are closely associated with the lung cavity. The pattern of release of hormone which this arrangement implies may have been adopted to ensure a rapid distribution of hormone throughout the circulation following release, or to increase the concentration of hormone in blood flowing through target organs such as the kidney, lung walls or the heart.

The Present Situation and Trend of Green Building Development in China Dongying City

2013 ◽  
Vol 357-360 ◽  
pp. 463-466
Author(s):  
Yu Xi Song
Keyword(s):  
Sustainable Development ◽  
Green Building ◽  
Present Situation ◽  
Building Industry ◽  
Primary Stage ◽  
Dark Green ◽  
Dongying City ◽  
Common Understanding ◽  
Light Green

In recent years, with the accelerating global resources depletion and increasing environment deterioration,sustainable development has become common understanding of best strategy in long-term development of human being. Green building has been the hottest keyword in building industry. This paper expounds the updated research of green building situation and trend,and investigate the green building development of DongYing City. The results indicated that green building development in China was still in the primary stage,the evaluation of green building would become national popular,the number of certified green building would increase year by year,and the development of green building in China was in the stage from light green to dark green.

Proneural clusters: equivalence groups in the epithelium of Drosophila

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 927-932 ◽  
Author(s):  
P. Simpson ◽  
C. Carteret
Keyword(s):  
Nervous System ◽  
Cell Lineage ◽  
Cellular Interactions ◽  
Equivalence Group ◽  
Neural Fate ◽  
Axonal Projections ◽  
The Central Nervous System ◽  
Neuronal Specificity ◽  
Proneural Cluster ◽  
Do So

The segregation of neural precursors from epidermal cells during development of the nervous system of Drosophila relies on interactions between cells that are thought to be initially equivalent. During development of the adult peripheral nervous system, failure of the cellular interactions leads to the differentiation of a tuft of sensory bristles at the site where usually only one develops. It is thus thought that a group of cells at that site (a proneural cluster) has the potential to make a bristle but that in normal development only one cell will do so. The question addressed here is do these cells constitute an equivalence group (Kimble, J., Sulston, J. and White, J. (1979). In Cell Lineage, Stem Cells and Cell Determination (ed. N. Le Douarin). Inserm Symposium No. 10 pp. 59–68, Elsevier, Amsterdam)? Within clusters mutant for shaggy, where several cells of a cluster follow the neural fate and differentiate bristles, it is shown that these display identical neuronal specificity: stimulation of the bristles evoke the same leg cleaning response and backfilling of single neurons reveal similar axonal projections in the central nervous system. This provides direct experimental evidence that the cells of a proneural cluster are developmentally equivalent.

A Preparation of Aplysia Fasciata For Intrasomatic Recording and Stimulation of Single Neurones During Locomotor Movements

1971 ◽  
Vol 54 (3) ◽  
pp. 659-676
Author(s):  
R. G. DE WEEVERS
Keyword(s):  
Ganglion Cells ◽  
Pedal Ganglion ◽  
Preliminary Results ◽  
Single Neurones ◽  
Sensory Responses ◽  
Motor Cells ◽  
Aplysia Fasciata ◽  
Pleural Ganglion ◽  
Somatic Musculature ◽  
Stimulation Of

1. Methods are described for suspending and clamping Aplysia fasciata so as to permit intrasomatic recording from neurones of the head ganglia during locomotor and other behavioural activities. 2. Sensory responses of neurones in the pedal ganglion are classified into four main types, all being distinct from those of pleural ganglion cells. 3. The pedal ganglion may well contain ‘motor cells’ for the greater part of the somatic musculature. 4. Preliminary results suggest that the pleural LGC may be involved in promoting a change from swimming to creeping behaviour.

Coordination of locomotor and cardiorespiratory networks of Lymnaea stagnalis by a pair of identified interneurones

1991 ◽  
Vol 158 (1) ◽  
pp. 37-62 ◽  
Author(s):  
N. I. Syed ◽  
W. Winlow
Keyword(s):  
Body Wall ◽  
Lymnaea Stagnalis ◽  
The Body ◽  
Whole Body ◽  
Pond Snail ◽  
Selective Ablation ◽  
The Central Nervous System ◽  
Body Wall Muscles ◽  
Bilateral Pair ◽  
Left And Right

1. The morphology and electrophysiology of a newly identified bilateral pair of interneurones in the central nervous system of the pulmonate pond snail Lymnaea stagnalis is described. 2. These interneurones, identified as left and right pedal dorsal 11 (L/RPeD11), are electrically coupled to each other as well as to a large number of foot and body wall motoneurones, forming a fast-acting neural network which coordinates the activities of foot and body wall muscles. 3. The left and right sides of the body wall of Lymnaea are innervated by left and right cerebral A cluster neurones. Although these motoneurones have only ipsilateral projections, they are indirectly electrically coupled to their contralateral homologues via their connections with L/RPeD11. Similarly, the activities of left and right pedal G cluster neurones, which are known to be involved in locomotion, are also coordinated by L/RPeD11. 4. Selective ablation of both neurones PeD11 results in the loss of coordination between the bilateral cerebral A clusters. 5. Interneurones L/RPeD11 are multifunctional. In addition to coordinating motoneuronal activity, they make chemical excitatory connections with heart motoneurones. They also synapse upon respiratory motoneurones, hyperpolarizing those involved in pneumostome opening (expiration) and depolarizing those involved in pneumostome closure (inspiration). 6. An identified respiratory interneurone involved in pneumostome closure (visceral dorsal 4) inhibits L/RPeD11 together with all their electrically coupled follower cells. 7. Both L/RPeD11 have strong excitatory effects on another pair of electrically coupled neurones, visceral dorsal 1 and right parietal dorsal 2, which have previously been shown to be sensitive to changes in the partial pressure of environmental oxygen (PO2). 8. Although L/RPeD11 participate in whole-body withdrawal responses, electrical stimulation applied directly to these neurones was not sufficient to induce this behaviour.

Green political philosophy

2018 ◽  
Author(s):  
Terence Ball
Keyword(s):  
Political Philosophy ◽  
General Rule ◽  
First Century ◽  
Environmental Crisis ◽  
Sea Levels ◽  
Nature Conservancy ◽  
Ice Caps ◽  
Dark Green ◽  
Light Green ◽  
Wind And Water Erosion

All the major political philosophies have been born of crisis. Green political philosophy is no exception to this general rule. It has emerged from that interconnected series of crises that is often termed ‘the environmental crisis’. As we enter the second decade of the twenty-first century it seems quite clear that the level and degree of environmental degradation and destruction cannot be sustained over the longer term without dire consequences for human and other animal species, and the ecosystems on which all depend. A veritable explosion in the human population, the pollution of air and water, the melting of the polar ice caps and the resulting rise in sea levels, the overfishing of the oceans, the destruction of tropical and temperate rain forests, the extinction of entire species, the depletion of the ozone layer, the build-up of greenhouse gases, global warming, desertification, wind and water erosion of precious topsoil, the disappearance of valuable farmland and wilderness for ‘development’ – these and many other interrelated phenomena provide the backdrop and justification for the ‘greening’ of much of modern political thinking. The task of outlining and summarizing the state of green political philosophy is made more difficult because there is as yet no agreement among ‘green’ political thinkers. Indeed there is, at present, no definitive ‘green political philosophy’ as such. The environmental or green movement is diverse and disparate, and appears in different shades of green. These range from ‘light green’ conservationists to ‘dark green’ deep ecologists, from ecofeminists to social ecologists, from the militant ecoteurs of Earth First!, to the low-keyed gradualists of the Sierra Club and the Nature Conservancy. These groups differ not only over strategy and tactics, but also over fundamental philosophy as well. While there is no single, systematically articulated and agreed-upon green political philosophy, however, there are nonetheless recurring topics, themes, categories and concepts that are surely central to such a political philosophy. These include the idea that humans are part of nature and members of a larger and more inclusive ‘biotic community’ to which they have obligations or duties. This community includes both human and nonhuman animals, and the conditions conducive to their survival and flourishing. Such a community consists, moreover, not only of members who are alive but those who are as yet unborn. A green political philosophy values both biological and cultural diversity, and views sustainability as a standard by which to judge the justness of human actions and practices. Exactly how these themes might fit together to form some larger, systematic and coherent whole is still being worked out.

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