title: The effect of carvacrol on muscarinic receptors of guinea-pig tracheal chains.
abstract: The effects of three concentrations of carvacrol, the constituent of Zataria multiflora Boiss (a monoterpenoid phenol, C(10) H(14) O) and 10 nm atropine on muscarinic receptors were tested on: non-incubated (n = 7), incubated tracheal chains with propranolol and chlorpheniramine (n = 6) and incubated with propranolol (n = 5). The EC(50) of all three concentrations of carvacrol in incubated tissues with propranolol and chlorpheniramine was significantly greater than those of incubated tissues with propranolol and non-incubated trachea (p < 0.05 to p < 0.001). The EC(50) of two higher concentrations of carvacrol (0.2 and 0.4 µg/mL) in incubated tissues with propranolol was also significantly greater than those of non-incubated trachea (p < 0.01 to p < 0.001). The maximum response in the presence of all concentrations of carvacrol in non-incubated and incubated tissues with propranolol and chlorpheniramine and those of its two higher concentrations (0.2 and 0.4 µg/mL) in incubated tissues with propranolol were lower than saline (p < 0.05 to p < 0.001). There were parallel rightward shifts in the concentration-response curves in the presence of all concentrations of carvacrol in non-incubated and incubated tissues with propranolol and its lower concentration in incubated tissues with propranolol and chlorpheniramine. These results indicated an inhibitory effect of carvacrol on muscarinic receptors. A β-adrenoceptor stimulatory effect was also suggested for carvacrol.
authors.affiliation: Department of Physiology and Pharmaceutical Research Centre, Medical School Mashhad University of Medical Sciences, Mashhad, Iran. boskabadymh@mums.ac.ir
authors.forename: M H
authors.initials: MH
authors.lastname: Boskabady
authors.forename: Z
authors.initials: Z
authors.lastname: Jafari
authors.forename: I
authors.initials: I
authors.lastname: Pouraboli
mesh_terms: D000818:Animals; D002744:Chlorpheniramine / Q000494:pharmacology; D000081007:Cymenes; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D039821:Monoterpenes / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000378:metabolism*; D014132:Trachea / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000081007:Cymenes; D039821:Monoterpenes; D011976:Receptors, Muscarinic; D016210:Methacholine Chloride; D002744:Chlorpheniramine; C073316:carvacrol; D011433:Propranolol