ISSN:
1432-0878
Keywords:
Brain vessels
;
Perivascular space
;
Connective tissue
;
Blood-brain-barrier
;
Lepidosteus (Ganoidei)
;
Teleosts
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Blood vessels surrounded by unusually wide perivascular spaces rich in connective tissue were observed in the brain of Lepidosteus (Ganoidei). Connective-tissue sheaths measuring up to 13 μm in width enclose arterioles and venules (40–70 μm in diameter), and even capillaries may be encompassed by a cuff formed by collagen fibers. Blood vessels with wide perivascular spaces are mainly located in the subependymal layer of the lateral ventricles, near the mesencephalic aqueduct and in the folded basal lining of the fourth ventricle. At the light-microscopic level these vessels do not show any distinct contact with nervous elements (axons). Some other brain regions of Lepidosteus, e.g. mesencephalic tectum, are supplied by a conventional type of capillaries, free of connective-tissue linings. For comparative reasons, brains of several selachian and teleostean species were examined with comparable histological methods. Distinct perivascular spaces were found in the pike, in the trout and in the eel. They are considerably richer in connective tissue than the occasionally observed narrow perivascular spaces in the shark. The significance of the abundant perivascular connective tissue in the brain of Lepidosteus is open to discussion; structural and functional problems of the brain-blood-barrier have been reviewed in this context. The brain of Lepidosteus appears to be a very suitable model for studies of blood supply, vascular ultrastructure and blood-brain-barrier functions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00231539
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