ISSN:0741-0581    

DOI:10.1002/jemt.1060120402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe field of neural transplantation has moved rapidly forward in the last decade. Initially, fetal cells were used as implants to investigate their potential to ameliorate deficits in animal models of Parkinson's disease. However, because of the moral and legal problems associated with the use of fetal tissues in humans, alternative sources of donor tissue were sought which possessed the structural and functional characteristics needed to improve motor function in Parkinsonian patients. To date, one of the most promising tissues being investigated is the adrenal medulla, whose chromaffin cells possess an inherent plasticity of form and function. Transplanted chromaffin cells currently are being studied by a variety of approaches, including electron microscopy, in mouse, rat, and primate models of Parkinson's disease. An overview of the role of the chromaffin cell in this exciting and clinically important arena is briefly reviewed, with an emphasis on the fine structure of implanted chromaffin cells.

ISSN:0741-0581    

DOI:10.1002/jemt.1060120403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractEvidence is presented for morphological proof of exocytosis in the rat adrenal medulla in situ. Techniques were modified to allow perfusion of the intact adrenal gland with secretagogues (or electrical stimulation) followed by tannic acid. Unstimulated specimens demonstrated exocytotic (omega‐shaped) profiles filled with flocculent material. This flocculation was also seen in the intercellular space. Stimulation of the adrenal medulla also resulted in the appearance of exocytotic profiles and an accumulation of the flocculent mass. This was often most evident in the subendothelial space. This is the first demonstration of exocytosis in the rat adrenal medulla by electron microscopy. The techniques used in this study will be useful for studying the pathway of secretory products of the adrenal chromaffin cell before they enter the vascular syste

ISSN:0741-0581    

DOI:10.1002/jemt.1060120404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractMitotic activity often has been reported in embryonic and fetal sympathetic neuroblasts, principal sympathoblasts, and primitive sympathetic cells in various species at different stages of development. Postnatal adrenal medullary cells also are known to undergo mitosis, but such dividing capabilities rarely have been observed in the true postnatal extraadrenal chromaffin system. Although few in number, this work nevertheless has clearly identified such cells in varying stages of the mitotic cycle in the young dog, Syrian hamster, mouse, rabbit, and rat. The dividing cells were noted in paraaortic chromaffin organs, paraganglia, and within the inferior mesenteric ganglion as well. They displayed the morphological character usually associated with their adrenal medullary catecholaminergic counterparts, including numerous dense‐cored vesicles known to be the harbingers of catecholamines and various peptides. Nerve endings were not noticed upon the mitotic cells. The phenomenon of dividing extraadrenal chromaffin cells augments existing data and perhaps suggests that these cells are more endocrine than neural in type and subservient to the adrenal medulla in its classic endocrine functio

ISSN:0741-0581    

DOI:10.1002/jemt.1060120405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractCurrent investigations on the immunohistochemical occurrence and co‐occurrence of biogenic polypeptides in the mammalian carotid body were reviewed and extended by our own recent findings. The family of chromogranins and related peptides in glomus cells appears to have a widespread interspecies distribution, whereas other peptides investigated occur in a species‐specific pattern. Immunoreactivity to antisera against opioids, which derive from the proenkephalin sequence, appears to be present in glomus cells of the rabbit, cat, dog, and a shrew. Conversely, glomus cells of pig and guinea pig predominantly are immunoreactive to cleavage products of prodynorphin, which co‐occur in some cells with substance P and met‐enkephalin‐arg‐phe, respectively. In the rat andCallithrix jacchus, opioid immunoreactivity is present in nerve fibres but not in glomus cells. Immunoreactivity to other peptides, such as neurotensin, cholecystokinin, neuropeptide Y, and galanin, is found only in one or two particular species. Neurotensin immunolabelling occurs in beagle dog glomus cells, which are known to lack substance P. Cholecystokinin immunoreactivity is present in glomus cells of dog andCallithrix, and co‐exists with chromogranin A, neuropeptide Y, and substance P. Substance P appears to exist in both carotid body glomus cells and nerve fibres. Substance P immunoreactivity is present in glomus cells of all species investigated, except dog. Coexistence of substance P and calcitonin gene‐related peptide (CGRP) is demonstrated in nerve fibres of the guinea pig carotid body, which originate in the petrosal and jugular ganglia. Other peptides visualized immunohistochemically in mammalian carotid body nerve fibres are vasoactive intestinal peptide and neuropeptide Y. The functional significance of the various peptides present in the carotid bo

ISSN:0741-0581    

DOI:10.1002/jemt.1060120406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractParaganglia are associated with every branch of the rat vagus nerve except the pharyngeal branch. Some of the paraganglia closely resemble the glomus caroticum, whereas others appear like small, intensely fluorescent (SIF) cells of autonomic ganglia. The paraganglionic cells of SIF cell‐like bodies (SLB) store catecholamines (the most abundant is probably noradrenaline) and in some cases neurotensin. The innervation pattern of SLB is variable and their physiological role remains unclear.Paraganglionic cells of glomus‐like bodies (GLB) predominantly store dopamine and probably also to a lesser extent noradrenaline. These putative chemoreceptor organs receive sensory innervation from nodose ganglion neurons as revealed by degeneration experiments and by anterograde neuronal tracing. Substance P‐ and calcitonin gene‐related peptide‐immunoreactive fibres seen in the region of vascular entry into the GLB may account for some of these sensory fibres, but the peptide/classical transmitter stored in sensory terminals synapsing on paraganglionic cells is unknown. Ultrastructural immunocytochemistry revealed vasoactive intestinal polypeptide (VIP)‐immunoreactive fibres lying in the interstitial space between paraganglionic cells and large capillaries. These fibres may originate from VIP‐immunoreactive neurons, being frequently attached to GLB. The major difference between GLB and the glomus caroticum concerns their blood supply and related innervation: Arteries and arterioles do not penetrate into GLB and, accordingly, noradrenaline‐ and neuropeptide Y‐containing nerve fibres are lacking within GLB. This peculiar arrangement of paraganglionic parenchyma and arterial blood supply may be one of the reasons for the different physiological properties of vagal and carotid arteri

ISSN:0741-0581    

DOI:10.1002/jemt.1060120407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractIn embedment‐free electron microscopy with polyethylene glycol embedding and subsequent deembedding, the conventional cytoplasm of the chromaffin cells was revealed to consist of a three‐dimensional lattice of microtrabeculae and gives the impression that the chromaffin granules are held in place by the lattice. After the restraint stress, a substantial number of chromaffin cells were almost free of granules, and the microtrabecular lattice was much more compact than that in cytoplasmic regions occupied with remaining granules or increased mitochondria. In immunocytochemistry, actin immunofluorescence was confined to the subplasmalemmal regions, while tubulin and tropomyosin immunofluorescence appeared throughout the entire cytoplasm of normal chromaffin cells. After the stress, the immunofluorescence for actin and tubulin increased in intensity, while that for tropomyosin decreased. Immunogold labelings for actin and tubulin were found mainly on the thinner subplasmalemmal microtrabeculae and the thicker perikaryal ones, respectively, while some were deposited in the form of small aggregates on portions of microtrabeculae. No specific association between the gold labelings for actin or tubulin and the chromaffin granules was found, even in the subplasmalemmal regions. A hypothetical interpretation was proposed in which a more compact lattice of the microtrabeculae in spatial association with a looser lattice represents a gelated state of the cytoplasm. The significance of the gel—sol transition of the cytoplasmic matrix in relation to the secretory mechanism was disc

ISSN:0741-0581    

DOI:10.1002/jemt.1060120408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe distribution of neuropeptides exhibits pronounced interspecies heterogeneity. Neuropeptides may function as hormones secreted from chromaffin cells or as neurotransmitters/neuromodulators released from nerve terminals. However, other possible functions such as trophic or intracellular effects should also be considered. Thus, to understand the role of neuropeptides, it is important to explore their localization in different species. The distribution of enkephalins, neurotensin, neuropeptide Y, calcitonin gene‐related peptide, and galanin in the adrenal medulla of rat, cat, hamster, and mouse is presented in detai

ISSN:0741-0581    

DOI:10.1002/jemt.1060120409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractEnkephalin‐like immunoreactivity in human adrenomedullary cells was studied at the light and electron microscopic levels. Enkephalin immunostaining was associated with chromaffin granules and, in a few cells, with the rough endoplasmic reticulum as well. The relative number of stained granules varied from cell to cell, and a correlation with a particular granular population was not noted. Both large and small granules were labelled. It is concluded that in the human the ability to store enkephalin immunoreactive peptides is a general property of chromaffin granules and, furthermore, is not correlated with specific granular subpopulations or the particular type of catecholamine stored within the cel

ISSN:0741-0581    

DOI:10.1002/jemt.1060120410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractLight and electron microscopic immunocytochemical techniques were used to study the effect of glucocorticoids on the development of phenylethanolamine‐N‐methyltransferase (PNMT)‐immunoreactive cells in the superior cervical ganglion (SCG) of early postnatal rats. Rats were injected daily with hydrocortisone acetate on postnatal days 2—6. The first PNMT‐immunoreactive cells were detected 6 hours after the first glucocorticoid injection and their number increased after subsequent injections. No PNMT‐immunoreactive cells were detected in uninjected controls. PNMT‐immunoreactive fibres were seen in the ganglion 6 hours after the first glucocorticoid injection. The PNMT‐immunoreactive cells consistently showed processes 2 days after beginning the glucocorticoid treatment, and long processes and fibre networks were seen in ganglia of 7‐day‐old rats. However, no PNMT‐immunoreactive fibres were seen in the iris, which is innervated by the SCG.Ultrastructurally, most of the PNMT‐immunoreactive cells had the look of small granule‐containing (SGC) cells, including heterochromatin clumps along the nuclear envelope and in the center of the nucleoplasm as well as dense core vesicles. SGC cells, nonimmunoreactive to PNMT antiserum, also were seen. However, some PNMT‐immunoreactive cells showed ultrastructural characteristics of nerve cells. In contrast to the SGC cells, these cells were characterized by a voluminous cytoplasm, dispersed nuclear heterochromatin, and a lack of granular vesicles. These results demonstrate that glucocorticoids induce PNMT immunoreactivity both in SGC cells and also in cells with character

ISSN:0741-0581    

DOI:10.1002/jemt.1060120411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY