Constitutive accessibility of circulating proteins to hippocampal neurons in physiologically normal rats.

Autor: Hamasaki S; Department of Anatomy, Faculty of Medicine, Tottori University, Yonago, Japan., Mukuda T; Department of Anatomy, Faculty of Medicine, Tottori University, Yonago, Japan., Koyama Y; Department of Anatomy, Faculty of Medicine, Tottori University, Yonago, Japan., Nakane H; Department of Anatomy, Faculty of Medicine, Tottori University, Yonago, Japan., Kaidoh T; Department of Anatomy, Faculty of Medicine, Tottori University, Yonago, Japan.
Jazyk: angličtina
Zdroj: Brain and behavior [Brain Behav] 2020 Mar; Vol. 10 (3), pp. e01544. Date of Electronic Publication: 2020 Jan 27.
DOI: 10.1002/brb3.1544
Abstrakt: Introduction: Although the hippocampus (HIP) is thought impermeable to blood-borne proteins because of the integrity of the blood-brain barrier (BBB), it was recently suggested to be susceptible to hydrophilic hormones. The present study determined the accessibility of blood-borne signal molecules such as hormones to hippocampal neurons in physiologically normal rats.
Methods: As a probe for accessibility, Evans blue dye (EB) that rapidly binds to albumin (Alb), which is impermeable to the BBB, was injected intravenously. To increase the vascular permeability of the BBB, a daily single administration of angiotensin II (Ang II) was applied intravenously for seven consecutive days.
Results: Fifteen minutes after the injection of EB, histological observation revealed that a number of neurons had entrapped and accumulated EB into their cell bodies in the hippocampal dentate gyrus in all rats. Of these, relatively large oval neurons (>15 µm) in the hilus and molecular layer showed parvalbumin immunopositivity, indicating they are GABAergic interneurons. The population of EB-accumulating neurons (approximately 10 µm) were localized in the inner margin of the granule cell layer, suggesting they were granule cells. However, the number of EB-positive neurons did not change in rats treated with Ang II compared with vehicle injection.
Conclusions: These findings suggest an intriguing possibility that blood-derived proteins such as hormones have access to hippocampal neurons constitutively in the absence of stimuli that increase the vascular permeability of the BBB in a physiologically normal state.
(© 2020 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.)
Databáze: MEDLINE
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