Scanning electron microscopic study of arterial cushions in rats: A novel application of the corrosion‐replication technique

Casellas, Daniel; Dupont, Madeleine; Jover, Bernard; Mimran, A

doi:10.1002/ar.1092030312

Cited by 25 publications

(20 citation statements)

References 23 publications

(27 reference statements)

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“…The retinal capillaries were extremely thin in diameter (3.0-4.0 µm), and red blood cells might barely pass through. The ridges at the origins of precapillary arterioles in the retinal and choroidal arteries represent intra-arterial cushions, which are sphincter-like thickenings of the intima, and play a significant role in regulating blood flow at the branching sites [4]. Our observation of these cushions in the retinal vessels is consistent with previous corrosion cast studies of ophthalmic arteries in rats [4,14], pigs [21], monkeys [13] and humans [9].…”

Section: Discussionsupporting

confidence: 89%

“…The ridges at the origins of precapillary arterioles in the retinal and choroidal arteries represent intra-arterial cushions, which are sphincter-like thickenings of the intima, and play a significant role in regulating blood flow at the branching sites [4]. Our observation of these cushions in the retinal vessels is consistent with previous corrosion cast studies of ophthalmic arteries in rats [4,14], pigs [21], monkeys [13] and humans [9]. The branching pattern with right angles, intra-arterial cushions and capillaries with extremely thin diameter may be responsible for causing plasma-skimming in the retinal capillary network [6,11,18].…”

Section: Discussionmentioning

confidence: 99%

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Microvascular Anatomy of the Pig Eye: Scanning Electron Microscopy of Vascular Corrosion Casts

Ninomiya

Inomata

2006

J. Vet. Med. Sci.

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ABSTRACT. The microvasculature of the eye of 10 pigs was investigated using scanning electron micrographs of corrosion casts. The ciliary body, iris and bulbar conjunctiva were supplied by the iridociliary ring artery via the long posterior ciliary artery. Capillaries of the ciliary process were of large diameter (23.2-27.5 µm) with an irregular bore, forming a thoroughfare channel draining blood in the ciliary arterioles into the pars plana venous vessels. Arterioles and venules in the iris exhibited a zigzag or spiral features. The third palpebra was supplied by the anterior ciliary artery. The capillary bed of the third palpebra was dense and was formed by many rows of fine hair-pin loops. Capillaries in the bulbar conjunctiva formed a sparse network disposing approximately parallel to the epithelium and formed a well-developed venous plexus, draining into the vortex veins. Retinal arterioles formed a slender and long course to capillaries. Retinal capillaries were extremely thin (3.0-4.0 µm in diameter). The choroid was supplied by the short posterior ciliary arteries.Choroidal arterioles exhibited a thick and short course to the choriocapillaris. The choriocapillaris was flat and sinusoid-like (8.9-13.9 µm in diameter), forming a dense sheet-like network. Blood from the choroid emptied into the episcleral vein via the vortex vein. Blood from the retina was drained by the posterior ciliary veins. The functional significance of this vascular architecture was discussed.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Microvascular Anatomy of the Pig Eye: Scanning Electron Microscopy of Vascular Corrosion Casts

Ninomiya

Inomata

2006

J. Vet. Med. Sci.

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“…The ridges at the origins of the precapillary arterioles in the retinal and choroidal arteries represent intra-arterial cushions, which are sphincter-like thickenings of the intima, and play a significant role in regulating blood flow at the branching sites. Our observation of these cushions in the raccoon retinal vessels is consistent with previous corrosion cast studies of ophthalmic arteries in rats [1,15], monkeys [14] and humans [10]. Plasma skimming is reported to occur in the retinal vessels [4,12].…”

Section: Discussionsupporting

confidence: 91%

Microvasculature of the Retina, Ciliary Processes and Choroid in the North American Raccoon (Procyon lotor) Eye: A Scanning Electron Microscopic Study of Corrosion Casts

Ninomiya

Inomata

Kanemaki

2005

The Journal of Veterinary Medical Science

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ABSTRACT. We have studied the vasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor), a nocturnal mammal, using light and scanning electron microscopic examination of corrosion casts. We carried out an identical study in the crab-eating macaque (Macaca fascicularis), which forages only during the daytime, in order to compare the ocular vasculature with that of nocturnal mammals. Our observations in raccoons demonstrated a photoreceptor layer associated with rich lymph and a poorly vascularized retina. The meridian region of the eye, which lies in the horizontal plane and pass around the optic disc, had a markedly sparse capillary network. This horizontal sparse vascular band may correspond to a visual streak. Ciliary process capillaries were delicate, and formed a well-developed and compact network. Choriocapillaries were quite thin and formed a coarse capillary network. This contrasted with the dense retinal and well-extended choroidal capillary networks noted in the macaques. Our findings suggest that the sparse retinal capillary network in raccoons is extremely beneficial for photon capture, thereby allowing the raccoon to see well at night, as the retinal vessels restrict the inflow of photons toward the photoreceptors. The well-developed lymph probably compensates for the sparse retinal capillaries and choriocapillaries and nourishes the retina in the nocturnal raccoon. KEY WORDS: corrosion casts, eye, raccoon, SEM, vasculature.J. Vet. Med. Sci. 67(6): 547-554, 2005 The North American raccoon (Procyon lotor) is a mammalian nocturnal omnivore that is found throughout most of the United States. Recently, they have also been found to be present throughout most of Japan. They were initially imported as pets but due to an increase in escaped or abandoned animals, their numbers have grown over the past decade, especially in urban and suburban areas. Raccoons cause a variety of problems, including feeding on dog or cat food, feeding on trash in garbage cans, establishing dens in attics or wall spaces, and/or causing damage to vegetable gardens. The raccoon is widely known for its habit of "washing" its food in water. The species name, lotor, actually means "the washer" in Latin. The animal has a very well-developed sense of touch, but its vision is not very good. The behavior in which they dunk their food in water looks like washing and is referred to as "dabbling". However, this "washing" of food items more than likely helps to enhance their sense of touch and assist them in finding food underwater through the use of their sensitive paws and digits. This action also enables them to sort out items that are not edible. Another nocturnal animal, the vizcacha (Lagostomus maximus maximus) [11], has an avascular retina, and rabbits [23], guinea pigs [19] and horses [19] are known to have poorly vascularized retinas. However, information on the vascular system of the raccoon eye has not been previously reported. Our study presents the results of light and scanning elect...

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“…The renal microvasculature has been studied in several species by corrosion casting methods: the rat [Casellas et al" 1982;Gattone et al, 1983a. b], the macaque monkey [Nopanitaya, 1980], the dog [Beeuwkes andBonventre, 1975: Anderson andAnderson.…”

Section: Discussionmentioning

confidence: 99%

Renal Microvasculature of the Black Bear (<i>Ursus americanus</i>)

Anderson

Anderson²,

Seguin³

1988

Cells Tissues Organs

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This study of the Black bear (Ursus amerícanus) was undertaken to provide basic information related to structural modifications in the renal microvasculature that might provide insight into the drastic alteration in renal urinary output that occurs during winter sleep. Vascular casts, as well as light microscopy and scanning electron microscopy, were used to study the vascular components of the juxtaglomerular complex and related vessels. Histologically, arterial cushions were readily identified at the origin of the afferent arterioles. In the area of the juxtaglomerular complex, the wall of the afferent arteriole appeared to be highly modified. The smooth muscle cells at this site demonstrated a change in morphology and orientation, and the diameter of the arteriole was altered. The pattern of the vascular casts at the origin of the afferent arteriole varied from that portion at the glomerulus, suggesting a modification of the vascular wall near the renal corpuscle. Although the morphology of the renal microvasculature of the Black bear is similar to that of other mammals in some aspects, it is dissimilar to that of other carnivores and of the human kidney in that there are structural modifications of the afferent arteriole that may contribute to a reduction of blood flow to the nephron during winter sleep.

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Scanning electron microscopic study of arterial cushions in rats: A novel application of the corrosion‐replication technique

Cited by 25 publications

References 23 publications

Microvascular Anatomy of the Pig Eye: Scanning Electron Microscopy of Vascular Corrosion Casts

Microvascular Anatomy of the Pig Eye: Scanning Electron Microscopy of Vascular Corrosion Casts

Microvasculature of the Retina, Ciliary Processes and Choroid in the North American Raccoon (Procyon lotor) Eye: A Scanning Electron Microscopic Study of Corrosion Casts

Renal Microvasculature of the Black Bear (<i>Ursus americanus</i>)

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