Microcirculation of the area postrema. Permeability and vascular responses.
- 1 August 1989
- journal article
- research article
- Published by Wolters Kluwer Health in Circulation Research
- Vol. 65 (2) , 417-425
- https://doi.org/10.1161/01.res.65.2.417
Abstract
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 fluorescein microscopy. Extravasation of sodium fluorescein (MW, 386), but not 150 kDa (MW) fluorescein isothiocyanate-dextran, occurred in the area postrema under control conditions. There was no extravasation of fluorescein or dextran in the brain stem under control conditions. Acute hypertension produced marked disruption of the barrier to 150 kDa dextran in the area postrema, compared with minimal disruption in the brain stem. We tested the hypothesis that the area postrema has greater permeability to small molecules than the brain stem and that this permeability might be accompanied by distinctive vascular responses. Topical suffusion of adenosine and ADP produced similar dose-related dilation of arterioles to area postrema and dorsal brain stem. Topical and intravenous vasopressin produced similar dose-related constriction of vessels to area postrema and brain stem. Electron microscopy in rats demonstrated that a barrier to horseradish peroxidase, which is absent in capillaries in the area postrema, is present in arterioles that supply the area postrema.(ABSTRACT TRUNCATED AT 250 WORDS)This publication has 28 references indexed in Scilit:
- Responses of cerebral arterioles to adenosine 5'-diphosphate, serotonin, and the thromboxane analogue U-46619 during chronic hypertension.Hypertension, 1988
- Role of area postrema pressor mechanisms in the regulation of arterial pressureCanadian Journal of Physiology and Pharmacology, 1987
- Area postrema is critical for angiotensin-induced hypertension in rats.Hypertension, 1987
- Resistance vessels supplying the median eminence of the rabbit, rat, and catThe Anatomical Record, 1984
- Factors involved in the physiological regulation of the cerebral circulationPublished by Springer Nature ,1984
- ADRENERGIC VASOCONSTRICTION OF NEUROHYPOPHYSEAL BLOOD VESSELSCritical Care Medicine, 1983
- Do pial terminal arterioles respond to local perivascular application of the neurohypophyseal peptide hormones, vasopressin and oxytocin?Brain Research, 1980
- Origin and Localization of Evans Blue Extravasations in Acutely-Induced Hypertension in CatsEuropean Neurology, 1978
- Entry of peroxidase into neurons of the central and peripheral nervous systems from extracerebral and cerebral bloodJournal of Comparative Neurology, 1976
- Note on the anatomy of the areae postremaeThe Anatomical Record, 1920