Virchows Archiv B

, 34:21 | Cite as

Ultrastructural observations on bifurcations in rat cerebral arteries

1. Young and aging rats

  • Masayasu Kojimahara
  • Genju Ooneda


The bifurcation pads seen at the sites of branchings of the anterior cerebral arteries in rats ranging in age from newborn to 20 months were examined electron microscopically. In young rats, intimai smooth muscle cells were arranged in one layer, and cellular contacts between the intimai cells and endothelial cells, and between the intimai cells were observed.

In adult rats, the pads showed valve-like projections or mound-like invaginations; they were rich ground substances and contained abundant elastic tissue. The pads were composed of intima. Cellular contacts between intimal cells and endothelial cells were observed, but no intimai or medial nerve fibers were seen. Cellular debris, mainly in the form of vesicles, granules and electron dense masses, was scattered within the bifurcations.

In aging rats, cellular debris was found mainly in the margins and roots of the pads. Marked alterations of the intima were present only immediately under severely damaged endothelial cells, but fibrinoid degeneration was not seen even in aging rats with severe medial damage. Basement membranelike substances were increased in bifurcations with advancing age.

The significance of bifurcation pads in the arterial walls was not clear, but it is suggested that they may be mobile physiological structures for regulating blood flow.

Key words

Bifurcation Cerebral artery Rat Cellular debris Physiological structure 


  1. Böck P (1975) Vergleich der Morphologie von Arterien- und Venenklappen. Verh Anat Ges 69:145–149PubMedGoogle Scholar
  2. Cliff WJ (1970) The aortic tunica media in aging rats. Exp Mol Pathol 13:172–189PubMedCrossRefGoogle Scholar
  3. Forbus WD (1930) On the origin of miliary aneurysms of the superficial cerebral arteries. Bull Johns Hopkins Hosp 47:239–284Google Scholar
  4. Fourman J, Moffat DB (1961) The effect of intra-arterial cushions on plasma skimming in small arteries. J Physiol 158:374–380PubMedGoogle Scholar
  5. Gerrity RG, Cliff WJ (1972) The aortic tunica intima in young and aging rats. Exp Mol Pathol 16:382–402PubMedCrossRefGoogle Scholar
  6. Gorgas K, Böck P (1975) Studies on intra-arterial cushions. I. Morphology of the cushions at the origins of intercostal arteries in mice. Anat Embryol 148:59–72PubMedCrossRefGoogle Scholar
  7. Gorgas K, Böck P (1976) Studies on intra-arterial cushions. II. Distribution of horseradish peroxidase in cushions at the origins of intercostal arteries in mice. Anat Embryol 149:315–321PubMedCrossRefGoogle Scholar
  8. Hassler O (1961) Morphological studies on the large cerebral arteries. With reference to aetiology of subarachnoid haemorrhage. Acta Psychiatr Neurol Scand [Suppl] 154:1–145Google Scholar
  9. Hassler O (1962) Physiological intima cushions in the large cerebral arteries of young individuals. 1. Morphological structure and possible significance for the circulation. Acta Path Microbiol Scand 55:19–27Google Scholar
  10. Jellinger K. (1966) Zur Frage der Arterienklappen im Nagelhirn. Anat Anz 119:246–258PubMedGoogle Scholar
  11. Joris I, Majno G (1974) Cellular breakdown within the arterial wall. An ultrastructural study of the coronary artery in young and aging rats. Virchows Arch [Pathol Anat] 364:111–127CrossRefGoogle Scholar
  12. Kojimahara M, Sekiya K, Ooneda G (1973) Age-induced changes of cerebral arteries in rats. An electron microscope study. Virchows Arch [Pathol Anat] 361:11–18CrossRefGoogle Scholar
  13. Kojimahara M, Ooneda G (1979) Electron microscopic study on the proximal portions of the anterior cerebral arteries in rats with long-term hypertension. Acta Pathol Jpn 29:183–196PubMedGoogle Scholar
  14. Lassmann H, Pamperl H, Stockinger G (1972) Intimalpolster der Arteria ophthalmica der Ratte in morphologisch-funktioneller Sicht. Z Mikrosk Anat Forsch 85:139–148PubMedGoogle Scholar
  15. Moffat DB, Creasey M (1970) The ultrastructure of intraarterial cushions. J Anat 107:191PubMedGoogle Scholar
  16. Moffat DB, Creasey M (1971) The fine structure of the intraarterial cushions at the origins of the juxtramedullary afferent arterioles in the kidney. J Anat 110:409–419PubMedGoogle Scholar
  17. Murphy RC, Webster RC (1966) A study of the cerebral arteries of rat. Anat Rec 154:478Google Scholar
  18. Ooneda G, Yoshida Y, Suzuki K, Sekiguchi T (1973) Morphogenesis of plasmatic arterionecrosis as the cause of hypertensive intracerebral hemorrhage. Virchows Arch [Pathol Anat] 361:31–38Google Scholar
  19. Ooneda G, Yoshida Y, Suzuki K, Shinkai H, Hori S, Kobori K, Takayama Y, Sekiguchi M (1978) Smooth muscle cells in the development of plasmatic arterionecrosis, arteriosclerosis, and arterial contraction. Blood Vessels 15:148–156PubMedGoogle Scholar
  20. Reale E, Luciano L (1966) Elektronenmikroskopische Beobachtungen an Stellen der Astgabe der Arterien. Angiologia 3:226–239Google Scholar
  21. Rhodin JAG (1967) The ultrastructure of mammalian arterioles and precapillary sphincters. J Ultrastruct Res 18:181–223PubMedCrossRefGoogle Scholar
  22. Rosen WC (1967) The morphology of valves in cerebral arteries of the rat. Anat Rec 157:481–487CrossRefGoogle Scholar
  23. Rotter W, Wellmer H-K, Hinrichs G, Müller W (1955) Zur Orthologie und Pathologie der Polsterarterien (sog. Verzweigungs- und Spornpolster) des Gehirns. Beitr Pathol Anat 115:253–294PubMedGoogle Scholar
  24. Sekiya K (1977) Pathomorphological study on the valve-like structures in the rat cerebral arteries. In Japanese (English abstr.). J Jpn Coll Angiol 17:171–181Google Scholar
  25. Shanklin WM, Azzam NA (1963 a) On the presence of valves in the rat cerebral arteries. Anat Rec 146:145–147PubMedCrossRefGoogle Scholar
  26. Shanklin WM, Azzam NA (1963b) A study of valves in the arteries of the rodent brain. Anat Rec 147:407–413PubMedCrossRefGoogle Scholar
  27. Stehbens WE (1975) Cerebral atherosclerosis. Intimai proliferation and atherosclerosis in the cerebral arteries. Arch Pathol 99:582–591PubMedGoogle Scholar
  28. Stehbens WE, Ludatscher RM (1973) Ultrastructure of the renal arterial bifurcation of rabbits. Exp Mol Pathol 18:50–67PubMedCrossRefGoogle Scholar
  29. Suzuki K, Hori S, Ooneda G (1979) Electron microscopic study on the medial defect at the apex of human cerebral arterial bifurcations. Virchows Arch [Pathol Anat] 382:151–161CrossRefGoogle Scholar
  30. Takayanagi T, Rennels ML, Nelson E (1972) An electron microscopic study of intimai cushions in intracranial arteries of the cat. Am J Anat 133:415–430PubMedCrossRefGoogle Scholar
  31. Wagenvoort CA (1954) Die Bedeutung der Arterienwülste für den Blutkreislauf. Acta Anat 21:70–99PubMedGoogle Scholar
  32. Weibel ER, Palade GE (1964) New cytoplasmic components in arterial endothelia. J Cell Biol 23:101–112PubMedCrossRefGoogle Scholar
  33. Yohro T, Burnstock G (1973) Fine structure of “intimai cushions” at branching sites in coronary arteries of vertebrates. Erg Anat Entwickl Gesch 140:187–202CrossRefGoogle Scholar
  34. Yoshida Y (1963) Pathology of hypertensive intracerebral hemorrhage, with special references to the morphogenesis of angionecrosis and arteriosclerosis in the intracerebral and middle cerebral arteries. (In Japanese, English abstr.). Trans Soc Pathol Jpn 51:726–762Google Scholar
  35. Yoshida Y, Ooneda G, Matsuyama K, Suto H, Murata S (1961) Morphogenesis of cerebral arteriosclerosis, with special reference to findings at the bifurcations of the middle cerebral and lenticulostriate arteries. Acta Pathol Jpn 11:244–245Google Scholar

Copyright information

© Springer-Verlag 1980

Authors and Affiliations

  • Masayasu Kojimahara
    • 1
  • Genju Ooneda
    • 2
  1. 1.Department of PathologyTakeda General HospitalAizuwakamatsuJapan
  2. 2.Department of Pathology, School of MedicineGunma UniversityMaebashiJapan

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