Summary
A submicroscopic study of the endothelium lining the blood capillaries and arterioles contained in the Cyon's nerve was made. The cytoplasm of some endothelial cells was found containing bundles of thin filaments. These measure about 60 Å in diameter, and do not show any cross striation, nor contacts with other cytoplasmic components. They are oriented parallel to each other and to the cell surface. No attachment plate of cytofilaments to the plasma membrane was seen. The filamentous structures were mostly found within the supranuclear cytoplasm. The endothelial cells in question never showed contacts with axons.
In the light of these findings it can be advanced the view that the cytofilaments present in endothelial cells are supportive in function; namely they may confer a higher elasticity to these cells, subject to continuous pressure and morphological variations.
Riassunto
Lo studio ultrastrutturale dell'endotelio di piccoli vasi sanguigni contenuti nel nervo cardio-aortico depressore di Cyon del coniglio ha consentito di rilevare la presenza in alcune cellule endoteliali di esili filamenti raggruppati in fasci più o meno numerosi. Detti citofilamenti presentano uno spessore di circa 60 Å, occupano per lo più il citoplasma sopranucleare e sono orientati parallelamente tra loro e rispetto alla superficie cellulare. Essi non mostrano struttura periodica né rapporto alcuno, se non di semplice contiguità, con altre componenti citoplasmatiche. Non presentano, inoltre, punti di attacco sulla membrana cellulare, né connessioni con fibre nervose. Numerose le vescicole pinocitotiche osservate lungo i bordi superficiale e basale delle cellule endoteliali in oggetto.
In base a tali reperti si avanza l'ipotesi che i citofilamenti endoteliali svolgano una funzione di sostegno nell'ambito del citoplasma, e siano capaci di conferire un più elevato grado di elasticità all'endotelio vasale, soggetto a continue variazioni di pressione e di forma.
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Dedicated to Prof. Wolfgang Bargmann on his 60th birthday.—This investigation was supported in part by a grant from the Italian C.N.R.
The author wishes to thank Dr. Pasquale Romeo for his kind help in the preparation of the paper, and Mr. Ciro Paesano for making the photographic prints.
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Cecio, A. Ultrastructural features of cytofilaments within mammalian endothelial cells. Z. Zellforsch. 83, 40–48 (1967). https://doi.org/10.1007/BF00334737
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DOI: https://doi.org/10.1007/BF00334737