title: On the atrophy of the internal carotid artery in capybara.
abstract: Capybara might be a useful model for studying changes in cerebral circulation as the natural atrophy of the internal carotid artery (ICA) occurs in this animal at maturation. In this study, confocal and electron microscopy combined with immunohistochemical techniques were applied in order to reveal the changes in morphology and innervation to the proximal part of ICA in young (6-month-old) and mature (12-month-old) capybaras. Some features of the basilar artery (BA) were also revealed. The ICA of young animals degenerated to a ligamentous cord in mature animals. Immunolabelling positive for pan-neuronal marker protein gene product 9.5 but negative for tyrosine hydroxylase was observed in the proximal part of ICA at both ages examined. Axon varicosities positive for synaptophysin were present in the adventitia of ICA of young animals but were absent in the ligamentous cord of mature animals. In the ICA of young animals, adventitial connective tissue invaded the media suggesting that the process of regression of this artery began within the first 6 months of life. An increase in size of the BA was found in mature animals indicating increased blood flow in the vertebro-basilar system, possibly making capybara susceptible to cerebrovascular pathology (e.g. stroke). Capybara may therefore provide a natural model for studying adaptive responses to ICA regression/occlusion.
authors.affiliation: Department of Anatomy and Developmental Biology, Hampstead Campus, Royal Free and University College Medical School, University College London, London NW3 2PF, UK.
authors.forename: Caroline
authors.initials: C
authors.lastname: Steele
authors.forename: Emerson T
authors.initials: ET
authors.lastname: Fioretto
authors.forename: Tais H C
authors.initials: TH
authors.lastname: Sasahara
authors.forename: Wanderley L
authors.initials: WL
authors.lastname: Guidi
authors.forename: Ana R
authors.initials: AR
authors.lastname: de Lima
authors.forename: Antonio A C M
authors.initials: AA
authors.lastname: Ribeiro
authors.forename: Andrzej
authors.initials: A
authors.lastname: Loesch
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001284:Atrophy; D001488:Basilar Artery / Q000033:anatomy & histology / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002343:Carotid Artery, Internal / Q000294:innervation / Q000378:metabolism* / Q000473:pathology* / Q000648:ultrastructure; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D008954:Models, Biological; D012377:Rodentia / Q000033:anatomy & histology*; D016708:Synaptophysin / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D015415:Biomarkers; D016708:Synaptophysin