Morphological observations on the unique paired capillaries of the opossum retina

Cell and Tissue Research
P G McMenamin, W J Krause

Abstract

Light-microscopic and ultrastructural analysis of the ocular tissues of the North American opossum (Didelphis virginiana) revealed that the arterial and venous segments of retinal vessels, including capillaries of the smallest calibre, occur in pairs. They do not form anastomotic networks, the common pattern in mammals with vascularised retinae, but instead the two segments of the pair join to form hairpin end loops. The paired vessels, with the arteriolar limb usually on the vitread aspect, penetrate the retina and branch to form three distinct layers of capillaries. The most superficial lies in the nerve fiber layer, the middle is situated in the inner nuclear layer and the deepest extends to the external limiting membrane, which is considerably deeper than in normal mammalian holangiotic retinae. The paired capillaries display classical morphological features of central nervous system capillaries, i.e., they are lined by continuous endothelial cells united by tight junctions. The lining endothelium is supported by a distinct basal lamina that splits to envelop pericytes. The latter, although abundant, are invariably interposed between the two vessels that form each vascular unit. Phylogenetic and functional aspects of this u...Continue Reading

References

Feb 1, 1992·Trends in Neurosciences·R F Mark, L R Marotte
Jan 1, 1990·Brain, Behavior and Evolution·R G ButteryK Bell
Sep 1, 1965·Experimental Eye Research·J M BloodworthR L Engerman
Jul 10, 1981·The Journal of Comparative Neurology·D H RapaportM H Rowe
Mar 10, 1981·The Journal of Comparative Neurology·E Tancred
Jul 1, 1958·The British Journal of Ophthalmology·J H YOUNG
Jul 1, 1958·Journal of Neurosurgery·L J LEMMENL L RADNOR
Sep 1, 1961·Experimental Eye Research·A T KISSEN, J M BLOODWORTH

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Citations

Apr 4, 2017·The Anatomical Record : Advances in Integrative Anatomy and Evolutionary Biology·Paul G McMenaminSamantha Dando
Jun 30, 1998·American Journal of Reproductive Immunology : AJRI·L LustigB Denduchis
Nov 23, 2017·Clinical & Experimental Ophthalmology·Sugapriyan Ravichandran, Paul G McMenamin

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