The area postrema is a circumventricular organ that plays an important role in neurohumoral regulation of the circulation. We have developed a method to examine permeability and vascular responses of the microcirculation of the area postrema in vivo. A craniotomy was performed over the dorsal brain stem in anesthetized rats, and blood vessels to the area postrema were visualized with fluorescen...

Neurotoxic substances affect the nervous system in a selective manner. One possible basis for this selectivity is blood vessel permeability. In general, the central nervous system and the peripheral nerve trunks have impermeable blood vessels, but in certain parts the capillaries are "leaky," allowing the passage of a plasma filtrate. Intravenously injected protein tracers rapidly reach nerve c...

The vasculature, composed of vessels of different morphology and function, distributes blood to all tissues and maintains physiological tissue homeostasis. In pathologies, the vasculature is often affected by, and engaged in, the disease process. This may result in excessive formation of new, unstable, and hyperpermeable vessels with poor blood flow, which further promotes hypoxia and disease p...

A B S T R A C T Systemic treatment of rats with captopril (50 mg/kg body wt per os), a specific competitive inhibitor of angiotensin 1-converting enzyme, significantly inhibits vascular permeability changes induced by the intradermal injection of the vasoactive mediators histamine, bradykinin, serotonin, and compound 48/80. This effect of captopril is both doseand time-dependent with '60% inhib...

Purification of the vascular permeability factor of Pseudomonas aeruginosa resulted in loss of activity and qualitative changes in skin lesions in rabbits. Addition to the purified vascular permeability factor of a macromolecular fraction with no vascular permeability factor activity restored the original characteristics of the skin reaction.

BACKGROUND Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) induces both angiogenesis and vascular permeability. Although its angiogenic activity has been well characterized, the signaling pathways of VEGF-induced permeability remain poorly understood. METHODS AND RESULTS Using the mouse corneal micropocket assay, Miles assay, and a combination of cytochemical, elect...