title: Eugenol and carvone as relaxants of arsenic and mercury hypercontracted rat trachea.
abstract: Exposure to arsenic and mercury is known to cause respiratory problems in both humans and animals. In this study, we elicit and compare maximum contraction caused by As(III) and Hg(II) when the pollutants are fully equilibrated with contractile machinery in resting mode. Hypercontraction of 27% and 69% was obtained following exposure of tracheal rings to 25 µM As(III) and 6 nM Hg(II) for 40 min, respectively. Co-incubation of tracheal rings with pollutants and verapamil, sodium nitroprusside or apocynin indicates that major contributors to As(III) and Hg(II) caused hypercontraction are reactive oxygen species (ROS) elevation and nitric oxide (NO) depletion. Changes in calcium influx have minor contribution in As(III) and Hg(II) caused increased contraction of tracheal tissues. Eugenol and carvone caused relaxation of 38% and 45% in pollutant unexposed rings, 56% and 49% in As(III)-exposed tracheal rings, and 54% and 47% in Hg(II)-exposed tracheal rings. Pathway delineation studies indicate that the major effect of eugenol originates from quenching of ROS whereas that of carvone originates from the blockage of extracellular calcium influx. Both molecules also show a minor stimulatory effect on NO generation. In line with their suggested mode of relaxation, eugenol is found to better ameliorate both As(III)- and Hg(II)-caused hypercontraction. Carvone, though a better relaxant than eugenol, comes out as poor ameliorator of both As(III)- and Hg(II)-caused hypercontraction, as the pathway on which it acts is not elevated following exposure to these pollutants.
authors.affiliation: Department of Biosciences, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi, India.
authors.forename: Swati
authors.initials: S
authors.lastname: Kundu
authors.affiliation: Department of Biosciences, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi, India.
authors.forename: Hiba
authors.initials: H
authors.lastname: Shabir
authors.affiliation: Department of Biosciences, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi, India.
authors.forename: Seemi F
authors.initials: SF
authors.lastname: Basir
authors.affiliation: Department of Biosciences, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi, India lkhan@jmi.ac.in.
authors.forename: Luqman A
authors.initials: LA
authors.lastname: Khan
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000818:Animals; D001151:Arsenic / Q000633:toxicity*; D000081005:Cyclohexane Monoterpenes; D005054:Eugenol / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008628:Mercury / Q000633:toxicity*; D039821:Monoterpenes / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D014132:Trachea / Q000187:drug effects* / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology
chemical_list: D000098:Acetophenones; D000081005:Cyclohexane Monoterpenes; D039821:Monoterpenes; D017382:Reactive Oxygen Species; D009599:Nitroprusside; D009569:Nitric Oxide; D005054:Eugenol; C006923:carvone; C056165:acetovanillone; D014700:Verapamil; D008628:Mercury; D001151:Arsenic
keywords: Arsenic; carvone; eugenol; hypercontraction; mercury; trachea