title: Mechanism of inhibitory effect of citalopram on isolated guinea-pig atria in relation to adenosine receptor.
abstract: The effect of citalopram (CTP), a selective serotonin reuptake inhibitor antidepressant was studied on the rate and force of contractions of isolated guinea-pig atria. CTP (2-32 microg/ml) caused a dose-dependent decrease in the contractile force (7%-62%) and in the rate of contractions (11%-72%). These negative inotropic and chronotropic effects of CTP (8 microg/ml) were not prevented by atropine (1 microg/ml) and 3,7 dimethyl-1-propargylxanthine (DMPX; 1.5 microg/ml), an adenosine A(2) receptor antagonist, but 1,3 dipropargyl-8-cyclopentylxanthine (DPCPX; 12 microg/ml), a specific adenosine A(1) receptor antagonist significantly blocked these effects (p < 0.001) and theophylline (30 microg/ml) a non-selective adenosine A(1)/A(2A) receptor antagonist also prevented the inotropic and chronotropic effects of CTP. These results suggest that the negative inotropic and chronotropic effect of CTP on isolated guinea-pig atria is probably mediated through an inhibition of the uptake of adenosine or the A(1) receptor mechanism.
authors.affiliation: Department of Pharmacology, Tehran University of Medical Sciences, Tehran, Iran. drpousti@yahoo.com
authors.forename: Abbas
authors.initials: A
authors.lastname: Pousti
authors.forename: Tara
authors.initials: T
authors.lastname: Deemyad
authors.forename: Golrokh
authors.initials: G
authors.lastname: Malihi
mesh_terms: D000818:Animals; D015283:Citalopram / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1 / Q000502:physiology*; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D015283:Citalopram; D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1; D017367:Selective Serotonin Reuptake Inhibitors