ABSTRACT
Pharmacological studies and traditional medical literature point to the cardiovascular effects of the Citrus aurantium L. [Rutaceae] in many instances. In the present study, we used isolated perfused AV-node of rabbit as an experimental model to determine the effect of various concentrations of essence of Citrus aurantium [0.1-0.3 v/v] on electrophysiological properties of isolated heart. The second goal of the present study was to assess the protective role of essence of Citrus aurantium on arrhythmogenic effects of ouabain. This was a semi-experimental study. We used isolated perfused rabbit AV-nodal preparation, in three groups. In the first group, the effect of various concentration of the Citrus aurantium [0.1, 0.2, 0.3 ml/l] was assesed on the AV-node. In the second and third groups, the effect of Citrus aurantium was tested in the presence of ouabain [0.1 micro molar] and verapamil [0.1 micro molar]. We used 6 rabbit in each group. Statistical analysis was preformed by SPSS Mean +/- SE was used in the all results. Our results showed depressant effects of extract of Citrus aurantium on Wenchebach Cycle Length [WBCL], AV Conduction Time [AVCT], Effective and Functional Refractory Periods [ERP and FRP]. Rate-dependent properties such as Facilitation and fatigue significantly increased by Citrus.a [0.3ml/l]. We had significant increase in the AVCT [32.6 +/- 3.6 to 40 /- 6.08 msec] and FRP [147 +/- 5.1 to 166.6 +/- 3.6 msec] by Citrus.a. We had a protective role of Citrus aurantium on ouabain induced AV-nodal depression. The magnitude of facilitation and fatigue in the concentration of 0.3 C.aurantium was 7.5 +/- 0.3 and 6.5 +/- 0.5, respectively. The above results indicated potential inhibitory and antiarrhythmic effect of Citrus aurantium in treating supraventricular tachyarrhythmia