Poster
# 52
Poster |
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6th Internet World Congress for Biomedical Sciences |
Toshihiro Yorozuya(1), Naoto Adachi(2), Masao Soutani(3), Kazuo Nakanishi(4), Kentaro Dote(5), Shigeo Kimura(6), Takumi Nagaro(7), Tatsuru Arai(8)
(1)(2)(3)(7)(8)Ehime-university School of Medicine - Japan
(4)(5)(6)Ehime university School of Medicine - Japan
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[Pharmacology] |
[Cardiolovascular Diseases] |
This study was approved by the Committee on Animal Experimentation at Ehime University School of Medicine, Ehime, Japan. Male ddY mice each weighing about 40 g (Japan SLC, Shizuoka, Japan) were housed in groups in a room controlled at 23}1 degrees C and maintained in an alternating 12-h light/12-h dark cycle (lights on at 0600 h). Animals were deprived of food at least 6 h before the start of experiments because of the influence of the plasma concentration of glucose. Forty-eight mice were prepared and then assigned to four saline groups and four dexamethasone groups (6 animals in each). Saline or dexamethasone (5 mg/kg) was administered intraperitoneally. Three hours after the administration, mice were killed by decapitation, and the heart was immediately removed and incubated in a glucose-free hypoxic phosphate buffer equilibrated with N2 (pH 7.4, 37 degrees C). The heart was frozen in liquid nitrogen after 5, 10, or 20 minutes of incubation. In the non-hypoxic (0 min) group, the heart was frozen immediately after its removal. The temperature of the temporal muscle was measured at the time of decapitation. The frozen heart was weighed and quickly homogenized with ice-cold 3 mL of 0.4 mol/L perchloric acid. After centrifugation at 20,000~g for 30 minutes, the supernatant was injected into a high-performance liquid chromatography (HPLC) system to determine the tissue concentrations of ATP, adenosine 5-diphosphate (ADP), and adenosine 5-monophosphate (AMP). The HPLC system consisted of a pump (L-7100, Hitachi, Tokyo, Japan) used to deliver the mobile-phase, a model L-7250 sample injector (Hitachi) with a 100-L sampling loop, a separation column (GL-W510-S, 7.8~300 mm inside diameter, Hitachi), and a UV detector (L-7400, Hitachi). The mobile phase was 0.2 mol/L NaH2PO4, with an adjusted pH of 3.5 with 0.2 mol/L H3PO4, and the flow rate was 0.5 mL/min. The absorption intensity (peak height) was measured at a wavelength of 270 nm. For comparison of values in the dexamethasone group to those in the saline group at corresponding times, an unpaired t test was used.
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[Pharmacology] |
[Cardiolovascular Diseases] |
