The perivascular spaces of ovine and canine brains (abstract)

Authors: Holle SA, Jolly RD, Hopcroft DH, Davies AS
Publication: New Zealand Veterinary Journal, Volume 42, Issue 2, pp 78, Apr 1994
Publisher: Taylor and Francis

Animal type: Companion animal, Dog, Livestock, Production animal, Ruminant, Sheep
Subject Terms: Circulatory system/haematology, Nervous system/neurology, Pathology
Article class: Abstract

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Abstract: The specialised histology and anatomy of the central nervous system (CNS) is reflected in its pathology. This is particularly so for the perivenular/periarterial spaces in which inflammatory cells accumulate in inflammation. These spaces, although structurally not lymphatics, act as lymphatics draining fluid from brain to subarachnoid space and to lymphatics draining to deep cervical lymph nodes. Inflammatory cells may enter or leave the CNS by this route. In immune-based inflammation, they are colonised by subsets of immune cells allowing the processing of antigen, synthesis of antibody and development of cell mediated immune reactions.
Light microscopy, transmission and scanning electron microscopy showed these structures in sheep and dogs to be similar to those previously shown for the rat and man⁽¹⁾. Perivenular spaces are delineated between the basal lamina covering the brain and the venule with spaces opening into the sub pial space. This latter occurs between the basal lamina and pia mater and contains collagen. Small arteries have two potential perivascular spaces. A periarterial space is formed between the muscular coat and basal lamina of the artery and a sleeve of pial cells which descends along the course of the artery and which may be fenestrated. An outer space also occurs between the pial sleeve and the basal lamina covering nervous tissue. The periarterial space may extend with arteries into the arachnoid and may be contiguous with lymphatics. Fixed macrophages may occur within the perivenular or periarterial spaces.
(1) Weller RO, Kida S, Zhang E-T. Pathways of fluid drainage from the brain - Morphological aspects and immunological significance in rat and man. Brain Pathology 2, 277-84, 1992.

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