Isolated Heart

Objective(s) In the present study, the effects of aqueous-ethanolic extract from Rosa damascena on heart rate and contractility were examined. Materials and Methods Isolated guinea-pig hearts were perfused through aorta in a Langendorff mode. Heart rate (HR) and contractility were determined in the presence of four concentrations of the extract (0.1, 0.2, 0.4 and 1.0 mg %) and isoprenaline (1, 10, 100 nM and 1 µM) in comparison with baseline values in the presence and absence of propranolol (n = 10 for each group). Results Both isoprenaline and the extract caused increase in heart rate and contractility (P< 0.05 to P< 0.001). The percent increased in HR due to the final concentration of isoprenaline in the absence of propranolol was significantly greater than that of the extract (P< 0.01). Propranolol caused significant reduction in both HR and contractility (P< 0.05 for both) but this effect was significantly reversed by isoprenaline and the extract (P< 0.05 to P< 0.001). The percent increased in heart contractility due to the final concentration of th