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Title: Blood flow measurements in rats using four color microspheres during blockade of different vasopressor systems
Authors: De Angelis, Katia
Gama, V. M.
Farah, VAM
Irigoyen, Maria Claudia [UNIFESP]
Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Univ Santo Amaro
Univ Sao Judas Tadeu
Keywords: colored microspheres
arterial pressure
sympathetic system
local blood flow measurement
Issue Date: 1-Jan-2005
Publisher: Assoc Bras Divulg Cientifica
Citation: Brazilian Journal of Medical and Biological Research. São Paulo: Assoc Bras Divulg Cientifica, v. 38, n. 1, p. 119-125, 2005.
Abstract: The use of colored microspheres to adequately evaluate blood flow chancres under different circumstances in the same rat has been validated with a maximum of three different colors due to methodological limitations. the aim of the present study was to validate the use of four different colors measuring four repeated blood flow. changes in the same rat to assess the role of vasopressor systems in. controlling arterial pressure (AP). Red (150,000), white (200,000)), yellow (150,000), and blue (200,000) colored microspheres were infused into the left ventricle of 6 male Wistar rats 1) at rest and 2) after vasopressin (aAVP, 10 mug/kg, iv), 3) renin-angiotensin (losartan, 10 ms/kg iv), and 4) sympathetic system blockade (hexamethonium., 20 mg/kg, iv) to determine blood flow changes. AP was recorded and processed with a data acquisition system (1-kHz sampling frequency). Blood flow changes were quantified by spectrophotometry absorption peaks for colored microsphere components in the tissues evaluated. Administration of aAVP and losartan slightly reduced the AP (-5.7 +/- 0.5 and -7.8 +/- 1.2 mmHg, respectively), while hexamethonium induced a 52 +/- 3 mmHg fall in AP. the aAVP injection increased blood flow in lungs (78%), liver (117%) and skeletal muscle (>150%), while losartan administration enhanced blood flow in heart (126%), lungs (100%), kidneys (80%), and gastrocnemius (75%) and soleus (94%) muscles. Hexamethonium administration reduced only kidney blood flow (50%). in conclusion, four types of colored microspheres can be used to perform four repeated blood flow measurements in the same rat detecting small alterations such as changes in tissues with low blood flow.
ISSN: 0100-879X
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