Pharmacodynamic interaction of garlic with propranolol in ischemia-reperfusion induced myocardial damage

The present study was undertaken to explore the interaction of garlic homogenate [GH] with propranolol [PRO] on ischemia-reperfusion injury [IRI] in isolated rat heart preparation. Albino rats were treated with GH at three different doses of 125 mg/kg, [GH-125], 250 mg/kg [GH-250] and 500 mg/kg [GH-500] for 30 days orally. The hearts were excised and mounted on modified Langendorff setup and subjected to 15 min global no flow ischemia and reperfused for 15 min. Pretreatment of animals with PRO, GH-125 and GH-250 [either alone or in combination] provided significant protection to myocardium from IRI damage as indicated by significant decrease in LDH and CK-MB activities in perfuste and an increase in activities of these enzymes in heart tissue homogenate. Similarly, the recovery [%] in developed tension and heart rate were significantly more in treated groups during post-ischemia when compared to control. Moreover, GH-250 either alone or with PRO showed significant increase in activities of antioxidant enzymes such as superoxide dismutase and catalase during IRI damage. However, GH-500 failed to show cardioprotective effect when given alone or along with PRO. These biochemical findings were supported by changes in histopathological studies

Communication: Effect of diperoxovandate on isolated rat heart

Diperoxovanadate (DPV); a product of vanadate is gaining importance as a biologically active vanadium compound. The aim of the present study was to evaluate the chronotropic and inotropic activity of DPV using isolated rat heart and to determine the concentration at which it is toxic to the heart. The study was carried out using modified Langendorff's setup. DPV was injected at varying concentrations (from 10-9 to 10-4) either as bolus (0.1 ml) or the heart was perfused continuously with varying concentrations of DPV for 10 min. Low concentration of DPV did not produce any significant effect on chronotropy and on developed tension. However; as the dose of DPV was increased; tension developed and heart rate was enhanced to significant extent (P 0.05) and both were found to be maximum at a dose of 10-7M. Further increase in DPV dose did not show either an increase in force or rate of contraction of heart but instead produced a relative decrease in both of these parameters when compared with the 10-7 M dose. When heart was perfused with a dose of 10-7 M DPV continuously for 10 min there was a significant increase in heart rate and developed tension (P 0.01). It was also found that at a dose of 10-5M; DPV showed not only further increase in developed tension but also produced marked disturbances in the rhythm indicating cardiac toxicity. This was further confirmed by lactate dehydrogenase (LDH) activity determination