• Dina Jragh, YousifMariam H MMHMDepartment of Pharmacology and Toxicology, College of Medicine, Kuwait University, Kuwait City, Kuwait., and Mabayoje A Oriowo.
• Department of Pharmacology and Toxicology, College of Medicine, Kuwait University, Kuwait City, Kuwait.
• Med Princ Pract. 2024 Jul 24: 181-8.

IntroductionEndogenous trace amines such as tryptamine and 3-iodothyronamine (T1AM) are present in mammalian tissues at very low concentrations. They produce their actions by activating surface G protein-coupled receptors known as trace amine-associated receptors (TAARs).ObjectiveThe study was designed to investigate the possible vasoconstrictor effects of tryptamine, T1AM, and the selective TAAR1 agonist RO5263397 in isolated perfused rat kidney.MethodsRenal vascular reactivity experiment using male Wistar Kyoto (WKY, n = 76) and spontaneously hypertensive rats (SHRs, n = 81) were used in this study.ResultsTryptamine (1011-106 mole), T1AM (1011-106 mole), and RO5263397 (1011-106 mole) increased perfusion pressure in preparations from WKY rats and SHRs in a dose-dependent manner. EPPTB, a selective TAAR1 antagonist (10-6 M), significantly (p < 0.05) reduced agonist-induced increase in perfusion pressure in both WKY rats and SHRs, suggesting a role for TAAR1 activation in these responses. The vasoconstrictor responses in both groups were significantly reduced by L-type dihydropyridine calcium channel blocker, Rho-kinase, and protein kinase C (PKC) inhibitors suggesting the involvement of extracellular calcium and enhanced calcium sensitization. Reactive oxygen species (ROS) scavenger TEMPO significantly inhibited the agonist-induced increase in perfusion pressure in preparations from SHRs but not WKY.ConclusionThe TAARs enhanced agonist-induced increase in perfusion causing vasoconstriction in the kidney involves the influx of extracellular calcium, increased calcium sensitization, and ROS in SHRs animals only.© 2024 The Author(s). Published by S. Karger AG, Basel.

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