Isolated heart preparations

Abstract Recently, we have investigated Aconitum cochleare Woroschin and obtained three new alkaloids cochleareine, acoleareine from the aerial parts of the plant and cochleareinine from the roots. Cochlearenine exhibited antioxidant activity against DPPH free radical scavenging assay. The cardio active effect of has also have been studied on isolated heart preparations. 

Cochlearenine (11) was tested on isolated heart preparations and caused a dose-dependent (0.3-3.0 mg/ml) fall in heart rate, while a mild increase in the atrial force... 

In isolated heart preparation, acetylcholine reduces the cardiac rate and in the presence of atropine, it can stimulate the heart causing ventricular arrhythmias. 

Studies of Arrhythmogenic Effects in Isolated Heart Preparations... 

These findings are consistent with impaired fatty-acid oxidation reduced mitochondrial entry of long-chain acylcarnitine esters due to inhibition of the transport protein (carnitine palmityl transferase 1) and failure of the respiratory chain at complex II. Another previously reported abnormality of the respiratory chain in propofol-infusion syndrome is a reduction in cytochrome C oxidase activity, with reduced complex IV activity and a reduced cytochrome oxidase ratio of 0.004. Propofol can also impair the mitochondrial electron transport system in isolated heart preparations. 

Langendorff preparation An isolated heart preparation used to test drug effects on heart rate and contractile force. 

Contractile force is measured in an isolated arterial preparation, and heart rate is measured in an isolated heart preparation. 

Contractile force is measured in an Isolated. arterial preparation and heart rate Is. measured In an Isolated heart preparation. 

The antiarrhythmic agent rythmol (78a) and its silicon analogue sila-rythmol (78b for the synthesis see Scheme 3) were evaluated on isolated heart preparations of the guinea pig (left atrium and papillary muscle) for their effects on contractility and on refractory... 

The accuracy of the model was tested using a servocontrolled isolated heart preparation (Janicki et aL, 1974) whereby it was possible to have controlled ejecting and isovolumetric contractions. The model parameters (i.e., AI-A6 and yj were calculated from the ejecting pressure-volume data and the model was then used to predict the peak isovolumetric pressure. When the predicted and measured peak isovolumetric pressure from 10 experiments were compared a correlation coefficient of 0.97 was found (Figure 3). Similar results have been obtained in open chest experiments with the heart intact. 

JANICKI I want to reply to the comment about the isolated heart preparation. First of all, I don t want to be in the position where I have to defend any model, but we did check out our models in the intact open chest dog where we could cross clamp it and were able to produce the isovolumetric relationships as well as the measured peak isovolumetric pressure. I think that the model does apply equally well to the open chest intact heart. 

The cardiovascular actions of ellipticine in the dog and monkey have been studied low doses of the drug, 10-18 mg/kg i.v. in the dog, 5-20 mg/kg i.v. in the monkey and 6-25-18-75 mg in the isolated blood-perfused dog s heart, appeared to stimulate beta receptors and this would be prevented by pretreatment with reserpine and (+ )-propanolol, but not (-(-)-propanolol. Higher doses produced a non cific depression of the cardiac function in the isolated heart preparation and the intact animals [116a]. 

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