The fine structure and innervation of the beta and delta cells in the islet of Langerhans of the cat

Legg, Peter G.

doi:10.1007/bf00339324

Cited by 80 publications

(18 citation statements)

References 19 publications

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“…A close relation between the islet endocrine cell and autonomic axons has repeatedly been reported in various mammals (BENCOSME, 1959;STAHL, 1963;LEGG, 1967;ESTERHUIZEN et al, 1968;WATARI, 1968;KOBAYASHI and FUJITA, 1969;WOODS and FORTE, 1974).…”

Section: Axon-islet Cell Relationshipsupporting

confidence: 59%

Proposal of a Neurosecretory System in the Pancreas

Fujita

Kobayashi

1979

Arch. Histol. Jap., Arch. Histol. Jpn

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Summary. The nerve fibers supplying the islets of the dog pancreas were examined by electron microscopy. Axons with swollen portions containing various types of synaptic vesicles, including a cholinergic type, two varieties of presumable aminergic type and a possible peptidergic type, rush to the pericapillary space to end there, whereas only a small part of them seem to terminate on the endocrine cells of the islet.Schwann cell cytoplasm invests the axons and often separates these from the endocrine cells. The terminal portions filled with vesicles usually become free of the Schwann sheath on the side facing the blood capillary. Here the neuronal secretions are believed to be released into the blood stream through the pored endothelium of the capillary.The neurosecretions, together with the islet hormones are distributed to the exocrine pancreas in high concentrations via the insulo-acinar portal system. It seems thus sufficient for the nerves to supply the islet in order to control the exocrine function of the pancreas.During the three decades since the establishment of the hypothalamo-hypophyseal neurosecretory system by BARGMANN (1949), the concept and criteria of neurosecretion have changed a great deal (LEDERIS, 1974;SANO, 1978). BARGMANN and SCHARRER (1951) regarded that stain-technologically demonstrable secretory granules are essential for a neurosecretory cell, but later this criterion had to be abandoned as newly discovered neurosecretory system producing and transporting releasing hormones from the hypothalamus to the hypophyseal portal vessels revealed no stainable granules. Recent advance in the knowledge of peptidergic neurons and of aminecontaining neurons occurring in different central and peripheral nervous tissues caused further confusion to the concept of neurosecretion. In agreement with SANO (1978), the last reliable criterion of neurosecretion (in higher vertebrates) must be that the neuronal secretions are released into the circulation and this is morphologically reflected in that the nerve terminals are not related to their target organ or cell but end in the perivascular (especially pericapillary) space.In the course of our electron microscope study of the dog pancreas, we recently noticed that numerous nerve terminals occur in the pericapillary spaces of the islet. Also by re-examining the electron micrographs which we produced for our previous *This paper is dedicated to the memory of the late Professor Wolfgang BARGMANN. 277

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Section: Axon-islet Cell Relationshipsupporting

confidence: 59%

Proposal of a Neurosecretory System in the Pancreas

Fujita

Kobayashi

1979

Arch. Histol. Jap., Arch. Histol. Jpn

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“…As recently reported by LEGG (1967) and WATARI (1968a, b), some unmyelinated nerve fibers enter the pancreatic islets of both the snake and yellow-tail fish, and terminate close to the islet cells forming nerve terminals with (Fig. 16b) or without membrane thickening (Fig.…”

Section: Yellow-tailsupporting

confidence: 74%

The Correlative Light and Electron Microscopy of the Islets of Langerhans in Some Lower Vertebrates

Watari

Tsukagoshi

Honma

1970

Arch. Histol. Jap., Arch. Histol. Jpn

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“…Lacy (1961), Lazarus andVolk (1962) Bj6rkman et al (1963), and Volk and Lazarus (1964) have described a process of emiocytosis, in which the granules migrate towards the cell membrane and are expelled in the extracellular space. Other authors (Munger 1962 Hellman 1964, Munger et al 1965, Lever and Findley 1966, and Legg 1967 have defended the view that insulin secretion can occur through an intracellular dissolution of granules or by direct secretion without passing through a granular form. Not the slightest evidence in favour of any of these mechanisms has been observed in our material.…”

Section: Discussionmentioning

confidence: 99%

The ultrastructure of the human pancreatic islets

1971

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Summary. The ultrastructure of the pancreatic islets was studied in seven surgical specimens of human pancreas. The effects of two different fixation methods were compared: osmium tetroxide alone and glutaraldehyde followed by osmium. On the basis of their ultrastructural characteristics, four main types of islet cells were identified: 1. B cells, with polymorphous, often crystalline granules contained in wide sacs. 2. A cells with rounded granules enclosed in tight fitting sacs and composed of an electron-dense core surrounded by a clearer halo. 3. Type III cells, with rounded, large homogeneous granules of varying sizes and electron densities. They presumably secrete gastrin. Comparable cells were found in samples of human gastric and duodenal mucosae. 4. Type IV cells, with rounded, small, homogeneous granules of low electron density. Comparable cells were found in human gastrie and duodenal mucosae. The nature of their secretion remains obscure. A fifth cell type was observed in the pancreas but was not restricted to the islets. Ceils of type V have small, polymorphous and very electron-dense granules. They offer a certain resemblance with the serotonin secreting cells which are found in the digestive tract. L'ultrastructure des ~tots de Langerhans de pancrgas humains. I. Lee ~lots des aduttesRdsumd. L'ultrastrueture des riots de Langerhans a 6t6 6tudi6e sur des pr616vements chirurgicaux de sept pancr6as humains. Les effets de la fixation par le t6troxyde d'osmium seulet par la glutarald6hyde suivie d'osmium ont 6t6 eompar6s. Quatre types eellulaires ont pu 6tre identifi6s: 1. Cellules B, ~ granulation polymorphe, de structure fr6quemment eristalline, incluses dans de larges v6sieules. 2. Cellules A k granules arrondis, eompos6s d'un noyau dense entour6 par un halo clair et inelus ~ l'6troit dans une enveloppe membranaire. 3. Cellules du type III grosses granulations arrondies, de structure homog6ne, de densit6 et de forme variables. Ces cellules s6cr6tent peut-6tre de la gastrine. Des 616ments similaires ont 6t6 rencontr6s dans les muqueuses gastrique et duod6nale. 4. Cellules du type IV, k petites granulations homog6nes et p&les. Des 616ments similaires ont 6t6 aper~us dans les muqueuses gastrique et duod6nale; leur fonetion reste inconnue. Des eellules d'un einqui6me type se voient dans le paner6as, m~me en dehors des ilots. Elles sont caract6-ris6es par de petits granules, tr6s denses et polymorphes: elles offrent une eertaine ressemblance avec les cellules s6rotonine que l'on trouve dans le tube digestif. Die Ultrastruletur der Inseln des menschlichen Pankreas. I. Die Inseln yon ErwachsenenZusamrnenfassung. Die Ultrastruktur der Langerhansschen Inseln wurde an Hand yon chirurgischen Probeexzisionen an 7 menschliehen Pankreata studiert. Die Ergebnisse der Fixierung durch Osmium-Tetraoxyd einerseits und dureh Glutaraldehyd gefolgt yon Osmium anderseits wurden vergliehen. So konnten vier Zelltypen identifiziert werden: 1. B-Zellen mit polymorphen, und oft kristallinen Granulationen, die in breiten S/~ekche...

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The fine structure and innervation of the beta and delta cells in the islet of Langerhans of the cat

Cited by 80 publications

References 19 publications

Proposal of a Neurosecretory System in the Pancreas

Proposal of a Neurosecretory System in the Pancreas

The Correlative Light and Electron Microscopy of the Islets of Langerhans in Some Lower Vertebrates

The ultrastructure of the human pancreatic islets

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