The role of adenosine receptors and endogenous adenosine in citalopram-induced cardiovascular toxicity

AIM: We investigated the role of adenosine in citalopram-induced cardiotoxicity. MATERIALS AND METHODS: Protocol 1: Rats were randomized into four groups. Sodium cromoglycate was administered to rats. Citalopram was infused after the 5% dextrose, 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX; A(1) receptor antagonist), 8-(-3-chlorostyryl)-caffeine (CSC; A(2a) receptor antagonist), or dimethyl sulfoxide (DMSO) administrations. Protocol 2: First group received 5% dextrose intraperitoneally 1 hour prior to citalopram. Other rats were pretreated with erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA; inhibitor of adenosine deaminase) and S-(4-Nitrobenzyl)-6-thioinosine (NBTI; inhibitor of facilitated adenosine transport). After pretreatment, group 2 received 5% dextrose and group 3 received citalopram. Adenosine concentrations, mean arterial pressure (MAP), heart rate (HR), QRS duration and QT interval were evaluated. RESULTS: In the dextrose group, citalopram infusion caused a significant decrease in MAP and HR and caused a significant prolongation in QRS and QT. DPCPX infusion significantly prevented the prolongation of the QT interval when compared to control. In the second protocol, citalopram infusion did not cause a significant change in plasma adenosine concentrations, but a significant increase observed in EHNA/NBTI groups. In EHNA/NBTI groups, citalopram-induced MAP and HR reductions, QRS and QT prolongations were more significant than the dextrose group. CONCLUSIONS: Citalopram may lead to QT prolongation by stimulating adenosine A(1) receptors without affecting the release of adenosine.