Cerebral blood flow determinations using fluorescent microspheres: variations on the sedimentation method validated

Powers, Karen M.; Schimmel, Carmel; Glenny, Robb W.; Bernards, Christopher M.

doi:10.1016/s0165-0270(98)00180-0

Cited by 25 publications

(18 citation statements)

References 11 publications

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“…All tissues were processed using previously established methods (68,80) with minor modifications. The tissue samples and reference blood samples were digested by adding freshly prepared 2.3 M KOH in ethanol with 0.5% Tween 80.…”

Section: Extraction Of Microspheresmentioning

confidence: 99%

Impact of chronic hypoxemia on blood flow to the brain, heart, and adrenal gland in the late-gestation IUGR sheep fetus

Paudel

McMillen

Dunn

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

106

107

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Section: Extraction Of Microspheresmentioning

confidence: 99%

Impact of chronic hypoxemia on blood flow to the brain, heart, and adrenal gland in the late-gestation IUGR sheep fetus

Paudel

McMillen

Dunn

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

106

107

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show abstract

“…Each tissue or reference blood sample was digested in ethanolic potassium hydroxide to recover trapped microspheres. 7 The microspheres recovered from each sample were dissolved in 2-ethoxyethyl acetate (3 mL) and the released fluorescent dyes were then assayed using a fluorometer (Model 814, Photon Technology International). Absolute tissue blood flow was calculated using the following equation:…”

Section: Experimental Protocolmentioning

confidence: 99%

Central Role of TRPM4 Channels in Cerebral Blood Flow Regulation

Reading

Brayden

2007

Stroke

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Background and Purpose-The transient receptor potential channel TRPM4 is critically linked to the myogenic constrictor response of cerebral arteries that occurs when intravascular pressure increases. This myogenic behavior is thought to be fundamentally involved in the mechanisms of blood flow autoregulation. In this study, we tested the hypothesis that TRPM4 channels in cerebrovascular myocytes contribute to cerebral blood flow autoregulation in vivo. Methods-In vivo suppression of cerebrovascular TRPM4 expression was achieved by infusing antisense oligodeoxynucleotides into the cerebral spinal fluid of 400-to 550-g Sprague-Dawley rats at 80 g ⅐ day Ϫ1 for 7 days using an osmotic pump that discharged into the lateral cerebral ventricle. Absolute cerebral blood flow measurements were obtained over a range of mean arterial pressures using fluorescent microsphere methods. Results-Oligonucleotides infused into the cerebrospinal fluid were detected in the smooth muscle cells of pial arteries.Semi-quantitative RT-PCR indicated that the message for TRPM4 was decreased in the cerebral arteries of antisense-treated rats. Myogenic constriction was decreased by 70% to 85% in cerebral arteries isolated from TRPM4 antisense-compared with control sense-treated rats. Cerebral blood flow was significantly greater in TRPM4 antisenseversus sense-treated rats at resting and elevated mean arterial pressures, indicating that autoregulatory vasoconstrictor activity was compromised in TRPM4 antisense-treated animals. Conclusions-In vivo suppression of TRPM4 decreases cerebral artery myogenic constrictions and impairs autoregulation, thus implicating TRPM4 channels and myogenic constriction as major contributors to cerebral blood flow regulation in the living animal.

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“…Because of their resistance to photo-bleaching, no care was made to prevent exposure of intact FMS to light. Dissected kidneys were stored in saline at 4 °C prior to digestion and fluorescence measurement, as described (Powers et al, 1999). If the right and left total kidney fluorescence values were not within 25% of each other, the animal was eliminated from the study due to lack of homogenous arterial FMS distribution.…”

Section: Determination Of Fms Concentrationmentioning

confidence: 99%

A modified fluorescent microsphere-based approach for determining resting and hyperemic blood flows in individual murine skeletal muscles

Cardinal

Hoying

2007

Vascular Pharmacology

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The goal of this study was to develop a modified fluorescent microsphere-based approach for measuring resting and hyperemic blood flows in individual mouse skeletal muscles. Absolute resting blood flow in the left gracilis posterior was 1.04±0.12 ml·min −1 ·g −1 , while functional hyperemia following muscle activity was 5.94±1.33 ml·min −1 ·g −1 . Measuring absolute blood flow requires sampling arterial blood that serves as a flow-rate and concentration reference to the fluorescent microsphere (FMS) content in the tissue-of-interest for calculating the flow value. Because sampling arterial blood can impair cardiovascular function in the mouse, we also modified our FMS approach to determine relative blood flows in the left gracilis posterior by using the contralateral muscle as our reference in blood flow calculations. Absolute and relative hyperemia measurements detect similar increases in blood flow -521.93±216.76% and 555.24±213.82%, respectively. However, sampling arterial blood during absolute blood flow measurements significantly decreased mean arterial pressure from the beginning to the end of our experiments, from 102.7±2.18 to 75.5±9.71 mm Hg. This decrease was not seen when measuring relative blood flows. This approach provides critical advantages over contemporary blood flow measurement approaches by allowing blood flow measurements in small and non-superficial tissues.

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Cerebral blood flow determinations using fluorescent microspheres: variations on the sedimentation method validated

Cited by 25 publications

References 11 publications

Impact of chronic hypoxemia on blood flow to the brain, heart, and adrenal gland in the late-gestation IUGR sheep fetus

Impact of chronic hypoxemia on blood flow to the brain, heart, and adrenal gland in the late-gestation IUGR sheep fetus

Central Role of TRPM4 Channels in Cerebral Blood Flow Regulation

A modified fluorescent microsphere-based approach for determining resting and hyperemic blood flows in individual murine skeletal muscles

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