Increased vesicular transfer of horseradish peroxidase across cerebral endothelium, evoked by acute hypertension

1977 ◽  
Vol 37 (2) ◽  
pp. 141-152 ◽  
Author(s):  
E. Westergaard ◽  
B. van Deurs ◽  
H. E. Brøndsted
Keyword(s):  
Horseradish Peroxidase ◽  
Cerebral Endothelium ◽  
Acute Hypertension

Ultracytochemical localisation of Na+, K+-ATPase in cerebral endothelium in acute hypertension

1990 ◽  
Vol 80 (1) ◽  
pp. 7-11 ◽  
Author(s):  
S. Nag
Keyword(s):  
Cerebral Endothelium ◽  
Acute Hypertension

scholarly journals Cerebrovascular Permeability in Mechanically Induced Hypertension

1981 ◽  
Vol 8 (3) ◽  
pp. 215-220 ◽  
Author(s):  
Sukriti Nag ◽  
David M. Robertson ◽  
Henry B. Dinsdale
Keyword(s):  
Horseradish Peroxidase ◽  
Abdominal Aorta ◽  
Drug Effect ◽  
Acute Hypertension ◽  
Principal Mechanism ◽  
Cerebrovascular Permeability ◽  
Induced Hypertension ◽  
Pinocytotic Vesicles ◽  
Interendothelial Junctions ◽  
Permeability Alterations

SUMMARY:Our previous studies of cerebrovascular permeability in angiotensin-induced acute hypertension demonstrated that the principal mechanism resulting in increased permeability is enhanced pinositose. In order to exclude the possibility that the enhanced pinositose was a direct effect of exogenous angiotensin, cerebrovascular permeability alterations were studied in nonpharmacologically induced acute hypertension.Rats receiving horseradish peroxidase (HRP) intravenously, were sacrificed 2½ minutes after the onset of hypertension induced by placing a clip on the abdominal aorta. These animals showed the same pattern of permeability alterations as had been observed previously in animals with angiotensin-induced acute hypertension. Focal segments of penetrating arterioles in the temporal and parietal cortex showed increased permeability to HRP. Permeable vessels showed increased numbers of pinocytotic vesicles and the interendothelial junctions revealed no alterations. Enhanced pinocytosis appears to be the principal mechanism resulting in increased cerebrovascular permeability in this model as well suggesting that the alterations of cerebrovascular permeability observed previously in angio-tensin-induced acute hypertension occur due to the hypertensive state and are not a direct drug effect of exogenous angiotensin.

scholarly journals Examination of the Blood-to-Brain Transfer of α-Aminoisobutyric Acid and Horseradish Peroxidase: Regional Alterations in Blood—Brain Barrier Function following Acute Hypertension

1986 ◽  
Vol 6 (4) ◽  
pp. 471-480 ◽  
Author(s):  
Mary D. Ellison ◽  
John T. Povlishock ◽  
Ronald L. Hayes
Keyword(s):  
Horseradish Peroxidase ◽  
Blood Brain Barrier ◽  
Brain Regions ◽  
Brain Barrier ◽  
Acute Hypertension ◽  
Aminoisobutyric Acid ◽  
Protein Extravasation ◽  
Blood Brain ◽  
Infusion Of Norepinephrine ◽  
The Brain

Blood–brain barrier (BBB) alterations following acute hypertension were studied in rats, employing as tracers in each animal both horseradish peroxidase (HRP) (MW 40,000) and [14C]α-aminoisobutyric acid ([14C]AIB) (MW 104). Eighteen animals were subjected to acute hypertension induced by the intravenous infusion of norepinephrine bitartrate (NE) (Levophed). Five animals injected with both tracers but not infused with NE served as controls. The brain of each animal was serially sectioned with adjacent sections processed either for macroautoradiography or for light microscopic visualization of HRP reaction product via histochemical reaction with tetramethylbenzidine. Quantitative blood-to-brain transfer constants for AIB were determined in each of 14 brain regions. Qualitative comparisons were also made between the AIB and HRP blood-to-brain extravasation patterns in each group. Acute hypertension increased cerebrovascular permeability to both AIB and HRP in most animals. Topographically, the sites of the most highly elevated AIB transfer corresponded with sites of HRP extravasation. Conversely, all sites of protein passage corresponded spatially to sites of elevated AIB transfer. Brain regions commonly showing increased permeability to both tracers included the cerebral cortices, corpus callosum, and thalamus. Importantly, some brain regions showed elevated AIB transfer constants where protein extravasation was absent. These regions included the caudate–putamen, hippocampus, basal forebrain, and cerebellum. These observations suggest that following acute hypertension, alterations in BBB permeability are not limited to vascular segments allowing protein extravasation.

Effects of Vincristine on Endothelial Microtubules in the Spinal Cord

1976 ◽  
Vol 34 ◽  
pp. 58-59
Author(s):  
John L. Beggs ◽  
John D. Waggener ◽  
Wanda Miller
Keyword(s):  
Spinal Cord ◽  
Biological Activity ◽  
Horseradish Peroxidase ◽  
Transport Mechanism ◽  
Vasogenic Edema ◽  
Vesicular Transport ◽  
Close Proximity

Microtubules (MT) are versatile organelles participating in a wide variety of biological activity. MT involvement in the movement and transport of cytoplasmic components has been well documented. In the course of our study on trauma-induced vasogenic edema in the spinal cord we have concluded that endothelial vesicles contribute to the edema process. Using horseradish peroxidase as a vascular tracer, labeled endothelial vesicles were present in all situations expected if a vesicular transport mechanism was in operation. Frequently,labeled vesicles coalesced to form channels that appeared to traverse the endothelium. The presence of MT in close proximity to labeled vesicles sugg ested that MT may play a role in vesicular activity.

Permeability of the microcirculation in area postrema of rat

1988 ◽  
Vol 46 ◽  
pp. 348-349
Author(s):  
Shams M. Ghoneim ◽  
Frank M. Faraci ◽  
Gary L. Baumbach
Keyword(s):  
Brain Stem ◽  
Area Postrema ◽  
Upper Body ◽  
Sprague Dawley ◽  
Sodium Cacodylate ◽  
Acute Hypertension ◽  
Sprague Dawley Rats ◽  
Ultrastructural Characteristics ◽  
The Brain ◽  
Adjacent Brain

The area postrema is a circumventricular organ in the brain stem and is one of the regions in the brain that lacks a fully functional blood-brain barrier. Recently, we found that disruption of the microcirculation during acute hypertension is greater in area postrema than in the adjacent brain stem. In contrast, hyperosmolar disruption of the microcirculation is greater in brain stem. The objective of this study was to compare ultrastructural characteristics of the microcirculation in area postrema and adjacent brain stem.We studied 5 Sprague-Dawley rats. Horseradish peroxidase was injected intravenously and allowed to circulate for 1, 5 or 15 minutes. Following perfusion of the upper body with 2.25% glutaraldehyde in 0.1 M sodium cacodylate, the brain stem was removed, embedded in agar, and chopped into 50-70 μm sections with a TC-Sorvall tissue chopper. Sections of brain stem were incubated for 1 hour in a solution of 3,3' diaminobenzidine tetrahydrochloride (0.05%) in 0.05M Tris buffer with 1% H2O2.

Comparative strengths and weaknesses of peroxidase and colloidal gold in pre- and post-embedding immunolabeling techniques

1987 ◽  
Vol 45 ◽  
pp. 1002-1005
Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Light Microscopy ◽  
Colloidal Gold ◽  
Light Microscope ◽  
Ultrastructural Localization ◽  
The Other ◽  
Quantitative Studies ◽  
Dense Suspension ◽  
Antigen Localization

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.

Unlabeled Antibody Immunocytochemistry Applied to Murine Mammary Tumor Cells

1975 ◽  
Vol 33 ◽  
pp. 390-391
Author(s):  
Wm. J. Arnold ◽  
J. Russo ◽  
H. D. Soule ◽  
M. A. Rich
Keyword(s):  
Horseradish Peroxidase ◽  
Mammary Tumor ◽  
Covalent Binding ◽  
Petri Dish ◽  
Gamma Chain ◽  
Mammary Tumor Virus ◽  
Mammary Tumor Cells ◽  
Murine Mammary Tumor ◽  
Tumor Virus ◽  
Unlabeled Antibody

Our studies of mammary tumor virus have included the application of the unlabeled antibody enzyme method of Sternberger to mammary tumor derived mouse cells in culture and observation with an electron microscope. The method avoids the extravagance of covalent binding of indicator molecules (horseradish peroxidase) with precious antibody locator molecules by relying instead upon specific antibody-antigen linkages. Our reagents included: Primary Antibody, rabbit anti-murine mammary tumor virus (MuMTV) which was antiserum 113 AV-2; Secondary Antibody, goat anti-rabbit IgG gamma chain (Cappel Laboratories); andthe Indicator, rabbit anti-horseradish peroxidase - horseradish peroxidase complex (PAP) (Cappel Labs.). Dilutions and washes were made in 0.05 M Tris 0.15 M saline buffered to pH 7.4. Cell monolayers, after light fixation in glutaraldehyde, were incubated in place by a protocol adapted from Sternberger and Graham and Karnovsky, then embedded by our usual method for monolayers. Reagents were confined to specific areas by neoprene 0-rings (Parker Seal Co.) reducing the amount of reagent needed to 50 microliters, 1/6th of that required to wet a 35 mm petri dish.

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