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Intracerebral arteriolar permeability to lanthanum
The American Journal of Pathology
|June 1, 1982
Summary
Lanthanum tracer studies reveal that normal brain arteriole tight junctions allow passage, contrary to prior beliefs. Acute hypertension accelerates this passage and increases vesicular transport in cerebral vessels.
Area of Science:
- Neuroscience
- Cell Biology
- Vascular Biology
Background:
- Lanthanum is an electron-dense tracer used to study cell junction structure.
- Interendothelial junctions in cerebral arterioles are critical for brain barrier function.
- The impact of acute hypertension on these junctions is not fully understood.
Purpose of the Study:
- To investigate lanthanum passage through normal intracerebral arteriole junctions.
- To document structural alterations in these junctions during acute hypertension.
Main Methods:
- Perfusion of lanthanum tracer in control and hypertensive animal models.
- Microscopic analysis of tracer distribution in cerebral microvasculature and surrounding tissue.
- Evaluation of endothelial cell structures, including tight junctions and pinocytotic vesicles.
Main Results:
- Lanthanum permeated normal intracerebral arterioles via endothelial cytoplasm and interendothelial spaces, suggesting a unique tight junction structure (maculae occludentes).
- Hypertension significantly accelerated lanthanum passage across arterioles, capillaries, and venules.
- Increased pinocytotic vesicle activity was observed in hypertensive cerebral arterioles.
Conclusions:
- Cerebral arteriole tight junctions differ from capillaries, featuring maculae occludentes rather than complete occluding bands.
- Acute hypertension compromises the blood-brain barrier, increasing permeability through both paracellular and transcellular pathways.
- Enhanced vesicular transport contributes to increased cerebral microvascular permeability in hypertension.