Quantitation of histamine-induced angiogenesis in the chick chorioallantoic membrane: mode of action of histamine is indirect.
Histamine was chosen as a standard chemical suitable for the development of new methods of assessing vascularity in the chick chorioallantoic membrane (CAM). When applied in liquid form to the entire 'dropped' area of CAM at day 10 of growth, a sublethal dose was required before a convincing appearance of increased vascularity was produced by day 15. Computer-assisted morphometry, using osmium-stained CAMs viewed en face, demonstrated a progressive increase in both length (21%) and number (59%) of arterial branches over 5 days relative to buffer only controls. A 56% increase in number of mesenchymal vessels seen in cross-section was also detected and this method is the quickest and easiest. No increase in the number of capillaries in the surface plexus of the ectoderm was found but this may be attributable to inadequate technique due to the already high density of capillaries present even in control CAMs using thin resin sections. However a 21% increase in the haemoglobin content of the CAM 4 days after histamine is consistent with an overall increase in the vascular bed. A rapid fall in DNA synthesis by 6 h (-48%) was produced by histamine, followed by a slow rebound to a peak at 36 h (74%). This contrasts with the growth factor type of pattern seen previously with fibrin degradation products giving a progressive rise to a major peak of DNA synthesis at 18 h. These effects indicate two mechanisms of induction of angiogenesis, and that the action of histamine is indirect.
Department of Pathology, University of Aberdeen, Scotland, UK.
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Thompson
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Brown
D000818:Animals; D001345:Autoradiography; D002196:Capillaries / Q000254:growth & development; D002642:Chick Embryo / Q000098:blood supply* / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D005321:Extraembryonic Membranes / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism; D006632:Histamine / Q000494:pharmacology*; D013997:Time Factors
D006632:Histamine; D004247:DNA