scholarly journals Nicotine Raises the Influx of Permeable Solutes across the Rat Blood—Brain Barrier with Little or No Capillary Recruitment

1995 ◽  
Vol 15 (4) ◽  
pp. 687-698 ◽  
Author(s):  
J.-L. Chen ◽  
L. Wei ◽  
D. Bereczki ◽  
F.-J. Hans ◽  
T. Otsuka ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Brain Areas ◽  
Nicotine Treatment ◽  
Influx Rate ◽  
Capillary Recruitment ◽  
Blood Brain ◽  
Solute Uptake ◽  
Permeability Surface

Nicotine (1.75 mg/kg s.c.) was administered to rats to raise local CBF (lCBF) in various parts of the brain, test the capillary recruitment hypothesis, and determine the effects of this increase in lCBF on local solute uptake by brain. lCBF as well as the local influx rate constants ( K1) and permeability-surface area ( PS) products of [14C]antipyrine and [14C]-3- O-methyl-d-glucose (30MG) were estimated by quantitative autoradiography in 44 brain areas. For this testing, the finding of significantly increased PS products supports the capillary recruitment hypothesis. In 17 of 44 areas, nicotine treatment increased lCBF by 30–150%, K1 of antipyrine by 7–40%, K1 of 30MG by 5–27%, PS product of antipyrine by 0–20% (mean 7%), and PS product of 30MG by 0–23% (mean 8%). Nicotine had no effect on blood flow or influx in the remaining 27 areas. The increases in lCBF and K1 of antipyrine were significant, whereas those in K1 of 30MG and in PS for both antipyrine and 30MG were not statistically significant. The lack of significant changes in PS products implies that in brain areas where nicotine increased blood flow: (a) essentially no additional capillaries were recruited and (b) blood flow within brain capillary beds rises by elevating linear velocity. The K1 results indicate that the flow increase generated by nicotine will greatly raise the influx and washout rates of highly permeable materials, modestly elevate those of moderately permeable substances, and negligibly change those of solutes with extraction fractions of <0.2, thereby preserving the barrier function of the blood–brain barrier.

Time courses of changes in cerebral blood flow and blood-brain barrier integrity by focal proton radiation in the rat

1996 ◽  
Vol 18 (1) ◽  
pp. 83-86 ◽  
Author(s):  
Hiroki Namba ◽  
Toshiaki Irie ◽  
Kiyoshi Fukushi ◽  
Masaomi lyo ◽  
Takahiro Hashimoto ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Proton Radiation ◽  
Barrier Integrity ◽  
Blood Brain ◽  
Time Courses ◽  
Blood Brain Barrier Integrity

Bidirectional saturable transport of LHRH across the blood-brain barrier

1991 ◽  
Vol 261 (3) ◽  
pp. E312-E318 ◽  
Author(s):  
C. M. Barrera ◽  
A. J. Kastin ◽  
M. B. Fasold ◽  
W. A. Banks
Keyword(s):  
Blood Brain Barrier ◽  
Ovarian Function ◽  
Brain Barrier ◽  
Multiple Time ◽  
Blood Brain ◽  
Permeability Surface ◽  
Cerebrovascular Permeability ◽  
The Difference ◽  
Single Time Point ◽  
Time Point

Systemic administration of luteinizing hormone-releasing hormone (LHRH) in rats has been found to influence behavior independently of pituitary or ovarian function. A previous study has shown that LHRH can cross the blood-brain barrier in one direction, but it was not known whether this was due to a saturable transport system. The rate of entry of 125I-labeled LHRH from blood to brain was determined by two different single-pass methods of carotid perfusion. The first, a multiple time point method, measures Ki from the slope of the linear regression when brain-to-blood ratios of radioiodinated LHRH are plotted against time. Saturable transport was determined by the difference between the Ki of rats perfused with 125I-LHRH (12.51 X 10(-3) mg.g-1.min-1) vs. rats perfused with 125I-LHRH and unlabeled LHRH (10 nmol/ml; 2.20 X 10(-3) ml.g-1.min-1). The inhibition by the unlabeled peptide was statistically significant (P less than 0.001). The second method, a single time point technique, measures the cerebrovascular permeability-surface area coefficient (PA). Saturable transport was determined in rats by the competition of unlabeled LHRH with 125I-LHRH. The PA value for 125I-LHRH (20.00 X 10(-3) ml.g-1.min-1) was significantly greater (P less than 0.05) than for 125I-LHRH with the addition of 10 nmol/ml unlabeled LHRH (4.14 X 10(-3) ml.g-1.min-1). Saturable transport of LHRH from brain to blood in mice was also determined.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals QuantitativeIn VitroandIn VivoEvaluation of Intestinal and Blood-Brain Barrier Transport Kinetics of the PlantN-Alkylamide Pellitorine

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Lieselotte Veryser ◽  
Nathalie Bracke ◽  
Evelien Wynendaele ◽  
Tanmayee Joshi ◽  
Pratima Tatke ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Rate Constant ◽  
Cell Monolayer ◽  
Elimination Rate ◽  
Brain Barrier ◽  
Apparent Permeability ◽  
Influx Rate ◽  
Blood Brain ◽  
Apical Side ◽  
The Brain

Objective.To evaluate the gut mucosa and blood-brain barrier (BBB) pharmacokinetic permeability properties of the plantN-alkylamide pellitorine.Methods.Pure pellitorine and anAnacyclus pyrethrumextract were used to investigate the permeation of pellitorine through (1) a Caco-2 cell monolayer, (2) the rat gut after oral administration, and (3) the BBB in mice after intravenous and intracerebroventricular administration. A validated bioanalytical UPLC-MS2method was used to quantify pellitorine.Results.Pellitorine was able to cross the Caco-2 cell monolayer from the apical-to-basolateral and from the basolateral-to-apical side with apparent permeability coefficients between0.6·10-5and4.8·10-5 cm/h and between0.3·10-5and5.8·10-5 cm/h, respectively. In rats, a serum elimination rate constant of 0.3 h−1was obtained. Intravenous injection of pellitorine in mice resulted in a rapid and high permeation of pellitorine through the BBB with a unidirectional influx rate constant of 153 μL/(g·min). In particular, 97% of pellitorine reached the brain tissue, while only 3% remained in the brain capillaries. An efflux transfer constant of 0.05 min−1was obtained.Conclusion.Pellitorine shows a good gut permeation and rapidly permeates the BBB once in the blood, indicating a possible role in the treatment of central nervous system diseases.

scholarly journals Effect of the Calcium Antagonist, Nimodipine, on Cerebral Blood Flow and Metabolism in the Primate

1981 ◽  
Vol 1 (3) ◽  
pp. 349-356 ◽  
Author(s):  
A. M. Harper ◽  
L. Craigen ◽  
S. Kazda
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Calcium Antagonist ◽  
Arterial Blood Pressure ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Arterial Blood ◽  
Blood Brain ◽  
Significant Change

The effect of the calcium antagonist nimodipine was tested in anaesthetised primates. A rapid intravenous injection of 3 or 10 μg kg−1 produced a transient rise in end-tidal Pco2 and a fall in arterial blood pressure, but 10 min after the injection there was no significant change in CBF. A continuous intravenous infusion of 2 μg kg−1 min−1 caused a modest fall in mean arterial blood pressure and an increase in cerebral blood flow (CBF), which gradually increased to 27% above control after 50 min infusion. There was no significant change in CMRO2. A continuous intracarotid infusion of 0.67 μg kg−1 min−1 caused an increase in CBF of between 46 and 57%. This was further increased to 87% above control after disruption of the blood-brain barrier with hyperosmolar urea. Thirty minutes after the urea, the CBF returned to 43% above control. Twenty minutes after the infusion of nimodipine had been stopped, the CBF had returned to control values. EEG studies in this group showed no obvious increase in electrocortical activity. This evidence suggests that nimodipine has no effect on cerebral metabolism but increases CBF, particularly after disruption of the blood-brain barrier.

Effect of sympathetic nerves on cerebral vessels during seizures

1979 ◽  
Vol 237 (2) ◽  
pp. H178-H184 ◽  
Author(s):  
S. M. Mueller ◽  
D. D. Heistad ◽  
M. L. Marcus
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Brain Barrier ◽  
Sympathetic Nerve Activity ◽  
Sympathetic Nerves ◽  
Brain Barrier ◽  
Blood Brain ◽  
Brain Barrier Permeability ◽  
Cervical Sympathetic ◽  
The Brain

The purpose of this study was to determine the effect of activation of sympathetic pathways during seizures on cerebral blood flow and integrity of the blood-brain barrier. We measured cerebral blood flow with microspheres and disruption of the blood-brain barrier with labeled albumin in cats. One cerebral hemisphere was denervated by cutting the superior cervical sympathetic trunk on one side. During bicuculline-induced seizures, superior cervical sympathetic nerve activity increased about threefold. Blood flow to the innervated hemibrain was significantly lower than flow to denervated hemibrain. However, in relation to the total increase in flow, this effect of nerves was minor. Blood-brain barrier permeability increased about sixfold during seizures, but there was no difference between the innervated and denervated sides of the brain. We conclude that sympathetic nerves attenuate the increase in cerebral blood flow during seizures, despite the increase in metabolism, but this effect is small. Activation of sympathetic nerves does not reduce disruption of the blood-brain barrier during seizures.

scholarly journals Blood—Brain Barrier Transport of Butanol and Water Relative to N-Isopropyl-p-Iodoamphetamine as the Internal Reference

1985 ◽  
Vol 5 (2) ◽  
pp. 275-281 ◽  
Author(s):  
William M. Pardridge ◽  
Gary Fierer
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Internal Reference ◽  
Diffusion Restriction ◽  
Blood Brain ◽  
Anesthetized Rats ◽  
Rat Forebrain ◽  
The Brain

The literature regarding the blood–brain barrier (BBB) transport of butanol is conflicting as studies report both incomplete and complete extraction of butanol by the brain. In this work the BBB transport of both [14C]butanol and [3H]water was studied using the carotid injection technique in conscious and in ketamine- or pentobarbital-anesthetized rats employing N-isopropyl- p-[125I]iodoamphetamine ([125I]IMP) as the internal reference and as a fluid microsphere. The three isotopes (3H, 125I, 14C) were conveniently counted simultaneously in a liquid scintillation spectrometer. IMP is essentially completely sequestered by the brain for at least 1 min in conscious rats and for 2 min in anesthetized animals. Butanol extraction by rat forebrain is not flow limited but ranges between 77 ± 1 and 87 ± 1% for the three conditions. The incomplete extraction of butanol by the forebrain is due to diffusion restriction of butanol clearance in some regions (frontal cortex, colliculi) but not in others (caudate, hippocampus, olfactory bulb). The permeability-surface area product/cerebral blood flow ratio of butanol and water in rat forebrain remains relatively constant, 1.7 ± 0.2 and 1.0 ± 0.1, respectively, despite a twofold increase in cerebral blood flow in conscious relative to pentobarbital-anesthetized rats. The absence of an inverse relationship between flow and butanol or water extraction is consistent with capillary recruitment being the principal mechanism underlying changes in cerebral blood flow in anesthesia. The diffusion restriction of BBB transport of butanol in some regions, but not in others, necessitates a careful regional analysis of BBB permeability to butanol prior to usage of this compound as a cerebral blood flow marker.

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