V Khori - Golestan Cardiovascular Research Center Golestan University of Medical Sciences Gorgan Iran
E Rakhshan - Golestan Cardiovascular Research Center Golestan University of Medical Sciences Gorgan Iran
A Mirabbas - Golestan Cardiovascular Research Center Golestan University of Medical Sciences Gorgan Iran
M Nayebpour - Department of Pharmacology Faculty of Pharmacy Tehran University of Medical Sciences Tehran

Biologically active substances of plant origin represent an essential branch of modern cardiovascular pharmacotherapy. Furthermore, drugs of plant origin have the advantage of weaker adverse effects and lower prices than synthetic drugs. Pharmacological studies and traditional medical literature point to the anti-ischemic and hypotensive effects of the Crocus sativus L. (Iridacea). The major goals of the present study were: (1) to determine the negative dormotrophic properties of a hydroalcoholic extract of saffron on an isolated AV node and (2) to establish the role of nitric oxide in the mediating effects of saffron on the electrophysiological properties of the AV node. This was an experimental study. Selective stimulation protocols were used to independently quantify AV nodal recovery, facilitation, and fatigue. We used isolated perfused rabbit AV node preparation, in three groups (N=32); in each group, we assessed the plant’s effect in comparison with the control. In the pilot study, we used different concentrations (A=9×10-2 mg/l, B=19×10-2 mg/l, and C=27×10-2 mg/l) to select the optimum concentration (19×10-2 mg/l) of the hydroalcoholic extract of Saffron. Saffron has a depressant effect on basic and rate-dependent properties of the AV node. We observed an increasing AVCT (38.8  4 to 41.7  4 msec) and FRP (157.6  3 to 163.7  4 msec). Also saffron increased the amount of facilitation and the magnitude of fatigue (5.9  0.3 to 11.1  1 msec). The NOS inhibitor (L-NAME) has a preventative effect on the depressant effect of saffron on AVCT and FRP.

arrhythmia, AV node, electrophysiology, nitric oxide (NO)