Studies <i>in situ</i> on the neurosecretory system of the earthworm, <i>Pheretima posthuma</i>

Dogra, G. S.

doi:10.1111/j.1469-7998.1968.tb08580.x

Cited by 7 publications

(3 citation statements)

References 26 publications

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“…Classification of NSCs in the cerebral ganglion of earthworms has been made chiefly on the basis of cytomorphological characteristics, their distribution and staining characteristics [12,[21][22][23][24][25][26][27][28]. Some of these observations agree with one another but many others differ.…”

Section: Discussionsupporting

confidence: 62%

“…According to Bianchi [33] amine secretion appears to be associated with the perikaryon and is being discharged directly into the blood stream. Thus in our present study prevalence of cytoplasmic vacuoles in the B cells, indicating direct discharge of NSM from the perikarya [28] Discrete axonal bundle, as found in insects [15] and chelicerate arthropods [35] although are not available in the cerebral ganglia of M. houlleti, M. posthuma, E. gammiei and E. eugeniae, a tendency for formation of such bundles become evident when A2 and B cells in their cerebral ganglia are examined. Such conditions are very likely due to the occurrence of 'pool' of these NSCs with functional importance.…”

Section: Discussionmentioning

confidence: 81%

“…Our earlier scanning electron microscopic studies on the cerebral ganglia of earthworm, E. gammiei revealed rich distribution of blood capillaries within the neuropile [38]. Thus margin of the vascularized neuropile that receive axon terminals from the NSC groups may serve the purpose of 'plexiform neurohaemal complex' [2], rudimentary [25], incipient [27] or elementary [28] neurohaemal organ. Abundance of NSM beneath the neural lamellae following their release from the superficial cortical cells is an interesting feature of the present investigation.…”

Section: Discussionmentioning

confidence: 99%

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Cytology and Histology of the Cerebral Neurosecretory Systems in some Tropical Earthworm Species

Chaudhuri¹

2015

J Cytol Histol

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The cerebral ganglia of tropical earthworms, Metaphire houlleti, Metaphire posthuma (Megascolecidae), Eutyphoeus gammiei (Octochaetidae) and Eudrilus eugeniae (Eudrilidae) revealed mainly two categories of neurosecretory cells (NSCs) -A cells and B cells. Thick cortical tier of A cells stained intensely with AF and were differentiated into A1, A2 and A3 types on the basis of their shape, size and location. The sub-cortical B cells, lying close to the neuropile stained lightly with AF. While the axons of A1 cells discharged neurosecretory material (NSM) beneath the perineurium, those of A2, A3 and B cells generally transported NSM at the margin of the neuropile forming "accumulation zone". Our present study revealed that in earthworms, in absence of any well-defined neurohaemal organ, there was a phenomenal deposition of NSM in the "accumulation zone" or tissue spaces beneath the highly vascular perineurium from where the secretion readily entered the capillaries by diffusion to meet the physiological demand of the animal.

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Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

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Cytology and Histology of the Cerebral Neurosecretory Systems in some Tropical Earthworm Species

Chaudhuri¹

2015

J Cytol Histol

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Histology of the neurosecretory system and the retrocerebral endocrine glands of the adult migratory grasshopper, Melanoplus sanguinipes (Fab.) (Orthoptera: Acrididae)

Dogra

Ewen

1970

Journal of Morphology

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Neurosecretory cells o f only one type (A, sub type Az) are seen in adult Melanoplus. Two groups of about 400 cells each are located dorsally in the pars intercerebralis medialis; four cells are located deep within the protocerebrum. We found no neurosecretory cells in other parts of the central or sympathetic nervous systems. In about 10% of the specimens, there was marked asymmetry in the location of the dorsal cell groups, with both of these groups and their axons located i n one lobe of the protocerebrum.The nervi corporis cardiaci 1 cross-over in the corpus cardiacum, with the result that material produced by neurosecretory cells on one side of the brain is transported along axons that undergo two chiasmata to the corpus cardiacum of the same side.Stainable secretory material could be traced clearly from the cerebral cells to the corpus cardiacum, and even into the oesophageal nerves from the hypocerebral ganglion. However, stainable neurosecretory material is never present in the corpus allatum or along any of the nerves to this gland.

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On the neurosecretory system of Dendrobaena atheca Cernosvitov

Baid

Gorgees

1977

Journal of Morphology

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A rudimentary neurohaemal organ, the storage zone, has been observed in the cerebral ganglion and there appears to be another neurohaemal area in the ventral nerve cord ganglion. The storage zone is formed by the terminal ends of the axons of A cells. The chrome alum haematoxylin phloxin (CHP) and aldehyde fuchsin (AF) positive substances in the form of granules are found in this area. The cerebral ganglion is richly supplied by blood capillaries. The distal end of the axons of B cells are swollen like a bulb while in some cases the axons are united to form an axonal tract. Extra-cellular material is abundant in different parts of the nervous system. In all cell types, the perinuclear zone is the first to show activity in the secretory cycle. It appears that the nucleus may be involved in the elaboration of the neurosecretory material in the cells.Neurosecretory cells with endocrine functions have been demonstrated in most major groups of triploblastic animals. Endocrinological studies were initiated in annelids by Scharrer ('36), though the neurosecretory cells were shown but misinterpreted by Hamaker (1898). Since then, the endocrinology of annelid worms has been the subject of a large number of experimental and ultrastructural investigations. Divergent opinions continued to be expressed about the types of the neurosecretory cells actually present in Oligochaeta. Scharrer and Scharrer ('37, '45, '54) Current evidence indicates that neurosecretory material is produced in the perikaryon of the cells, passes into the axons where it is temporarily stored and then released through the axon bulb (Rothballer, '66; Scharrer, '66; Dogra, '68). The mechanism of the release of the neurosecretory material has been considerably debated in recent years (De Robertis, '62; Heller and Lederis, '62; Knowles, '62; Bern, '63). The axon bulbs have special significance for the neurosecretory neurones, which combine the function of ordinary neurones with that of glandular cells. Furthermore, unlike the ordinary neurones, the neurosecretory cells do not form synapses by terminating a t the effector organ but instead they release their hormones either directly into the blood (Clark, '59, '661, or into an intermediate structure-the storage and release organ (Scharrer, '63). It is possible that there are two secretory pathways, an intra-cellular and inter-cellular, for the transportation of the neurosecretory material elaborated by the perikaryon (Dogra, '68). With the discovery of the neurohaemal organs, a neurosecretory x-organ sinus gland system in crustacea and inter-cerebralis-cardiacum-allatum system in insects have been established but such a system is still not known for annelids.It appears that the variations in the morphology of the neurosecretory cells, different ways of synthesis of hormones in these cells and the various modes of release of hormones in the absence of a well developed storage and release organs are of common occurrence in oligochaetes. The present paper describes the structure of the various types...

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Studies in situ on the neurosecretory system of the earthworm, Pheretima posthuma

Cited by 7 publications

References 26 publications

Cytology and Histology of the Cerebral Neurosecretory Systems in some Tropical Earthworm Species

Cytology and Histology of the Cerebral Neurosecretory Systems in some Tropical Earthworm Species

Histology of the neurosecretory system and the retrocerebral endocrine glands of the adult migratory grasshopper, Melanoplus sanguinipes (Fab.) (Orthoptera: Acrididae)

On the neurosecretory system of Dendrobaena atheca Cernosvitov

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