The effects of the duration of ischemia on coronary vasoconstriction after ischemia-reperfusion were analysed in rat hearts. After 15, 30 or 45 min of global zero-flow ischemia and 15 min reperfusion, the coronary response to endothelin-1 (10(-10)-10(-7) M) and the thromboxane A2 analogue 9,11-dideoxy-1a,9a-epoxymethanoprostaglandin F2alpha (U46691, 10(-8)-10(-6) M) was recorded. Vasoconstriction induced by endothelin-1 only increased after short 15 min periods of ischemia. In contrast, the vasoconstriction induced by U46619 remained unmodified by short ischemias but was reduced after longer periods of ischemia (30 and 45 min). Inhibition of nitric oxide synthesis with the Nw-nitro-L-arginine methyl ester (L-NAME, 10(-4) M) augmented the vasoconstriction induced by endothelin-1 in non-ischemic hearts, but not following ischemia. Similarly, L-NAME increased the vasoconstriction induced by U46619 to a greater extent in non-ischemic hearts than following ischemia. These results suggest that ischemia-reperfusion inhibits nitric oxide production, causing an increased coronary response to endothelin-1 after brief ischemias. Longer ischemias may non-specifically inhibit coronary vasoconstriction and reduce nitric oxide production.
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http://dx.doi.org/10.1016/j.ejphar.2004.11.065 | DOI Listing |
Sci Rep
December 2024
Department of Chemistry and Biochemistry, Centre for Research in Molecular Modeling (CERMM), Concordia University, 7141 Sherbrooke Street West, Montréal, QC, H4B 1R6, Canada.
Nitroglycerin is a potent vasodilator in clinical use since the late 1800s. It functions as a prodrug that is bioactivated by formation of an enzyme-based thionitrate, E-Cys-NO. This intermediate reportedly decomposes to release NO and NO but their relative yields remain controversial.
View Article and Find Full Text PDFMetaplastic breast cancer (MpBC) is a highly chemoresistant subtype of breast cancer with no standardized therapy options. A clinical study in anthracycline-refractory MpBC patients suggested that nitric oxide synthase (NOS) inhibitor NG-monomethyl-l-arginine (L-NMMA) may augment anti-tumor efficacy of taxane. We report that NOS blockade potentiated response of human MpBC cell lines and tumors to phosphoinositide 3-kinase (PI3K) inhibitor alpelisib and taxane.
View Article and Find Full Text PDFChem Biodivers
December 2024
Wuyi University, School of Pharmacy and Food Engineering, Yingbin Street NO.99, 529020, Jiangmen, CHINA.
Long-term use of naproxen can lead to serious side effects. Inspired by the biological activity of cinnamic acid, a series of cinnamic acid derivatives containing naproxen were designed, synthesized and explored their anti-inflammatory activities and mechanism in vitro. Our results indicated that all of naproxen derivatives showed more significant inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) production and had lower degree of cytotoxicity than that of naproxen.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
December 2024
Faculty of Science and Technology, Keio University, Yokohama, Japan.
Most actinomycetes and fungi have a multitude of silent biosynthetic genes whose activation could lead to the production of new natural products. Our group recently designed and used a co-culture method to isolate new natural products, based on the idea that pathogens might produce immune suppressors to avoid attack by immune cells. Here, we searched for compounds produced by the co-culture of immune cells with pathogenic fungi isolated from clinical specimens.
View Article and Find Full Text PDFOpen Vet J
November 2024
Theriogenology Department, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.
Background: Senility influences fertility in women and companion animals, especially horses.
Aim: This study aimed to investigate the effect of aging in horses on the daily changes in the dominant follicle (DF) dynamics and hemodynamics, antimüllerian hormone (AMH), enzymes, antioxidants, and ovarian hormones during the estrous cycle.
Methods: Ovaries of old mares ( = 5, age >20 years) and young native mares ( = 6, age <10 years) were scanned during 6 different estrous cycles from March 2022 to August 2023 with Doppler ultrasound.
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