Langendorf_heart
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THE LANGENDORFF HEART OR ISOLATED PERFUSED HEART ASSAY IS A PREDOMINANT IN VITRO TECHNIQUE USED IN PHARMACOLOGICAL AND PHYSIOLOGICAL RESEARCH USING ANIMALS. IT ALLOWS THE EXAMINATION OF CARDIAC CONTRACTILE STRENGTH, HEART ELECTROPHYSIOLOGY AND HEART RATE WITHOUT THE COMPLICATIONS OF AN INTACT ANIMAL. In the Langendorff preparation, the heart is removed from the animal’s body, severing the blood vessels; it is then perfused in a reverse fashion via the aorta, usually with a nutrient rich, oxygenated solution (e.g. Krebs–Henseleit solution or Tyrode’s solution). The backwards pressure causes...

langendorf heart GENERAL DESCRIPTION The animal is anesthetized and heparinized. The animal heart is removed from the chest cavity and suspended on perfusion cannula of Langendorff apparatus via aorta. The aortic root is tied. The coronaries are perfused with carbogenized, pH stabilized buffer solution. The temperature of the buffer is maintained by water-jacketed glassware. Two modes of perfusion can be carried out: constant pressure by hydrostatic pressure or constant flow mode by roller pump. Both methods provide retrograde perfusion when the aortic valve is permanently closed, so the...

MAMMALIAN SPECIES USED FOR ISOLATED HEART PERFUSION STUDIES • Mostly rat hearts due to its suitable size, but with restrictions due to different biochemistry Mice, mostly transgenic ones Rabbit, guinea pig, hamster, gerbil, ferret Larger mammal heart (pig, monkey, sheep, dog, human) can be perfused, however a completely different perfusion apparatus is required due to their

Krebs-Henseleit buffer Compound NaCl NaHCO3 KCl MgSO4 KH2PO4 Glucose CaCl2 EDTA-Na Pyruvate Insulin* Albumin* PROCEDURE FOR SALT MIXTURE Chemical Concentration (mM) langendorf heart ''ylamide-Bis Solution ;

CARBOGEN GAS FOR OXYGEN SATURATION AND PH SETTING When preparing the buffer solution, solution has to be bubbled with Carbogen gas (95% O2 and 5% CO2) for at least 10 to 15 minutes prior to adding the final component CaCl2 to avoid precipitation of calcium as phosphate salt. To avoid lack of oxygen and pH shift of the perfusion, the buffer solution has to be saturated with these gases. Saturation is temperature dependent. Solubility (g gas/kg water) The plasma pO2 level between 100-120 mmHg results 100% hemoglobin saturation in blood. Red blood cells serve as O2 storage and when the plasma...

It is important to know whether during bubbling the buffer with Carbogen the saturation is achieved or not. For checking O2 level in buffer a blood gas analyzer is used to check saturation. However, if such a device is not available in the lab, the temperature dependence of solubility can be used. When the bubbling is carried out at room temperature (approximately at 22-24 centigrade) more gas will be dissolved in the buffer compared to 37 centigrade. Bubbling should last approximately 1-hour prior filling the perfusion apparatus with it. When the reservoir(s) of the perfusion apparatus is...

Monika Skrzypiec-Spring, Bartosz Grotthus, Adam Szelag, Richard Schulz: Isolated heart perfusion according to Langendorff — Stillviable in the new millennium. Journal of Pharmacological and Toxicological Methods 55 (2007) 113–1

langendorf heart ANAESTHESIA • Avoid stressing of the animal • Prefer barbiturate, xylazine-ketamine • Inject heparin EXCISION OF THE HEART 1. Open abdomen longitudinally up to septum - make longitudinal incision 2. Push intestine sideway 3. Inject heparin to vena hepatica 5. Grab septum with an anatomical forceps 6. Cut ribs both side then cut diaphragm 7. Bend over chest 8. Grab heart, but do not sqeeze 9. Incise aorta, vena cava and pulmonary arteries as deep as possible 10. Drop incised heart into ice-cold KHB Balloon connected to pressure transducer CANNULATION • Buffer should be run...

INSTRUMENTS FOR MEASURING PARAMETERS LVDP – a fluid filled catheter with deflated latex balloon is inserted into the LV, a spindle syringe is used to inflate the balloon inside the LV to to be able to detect diastolic LVDP between 7-12 mmHg and systolic LVDP between 100-120 mmHg respectively. Monika Skrzypiec-Spring, Bartosz Grotthus, Adam Szelag, Richard Schulz: Isolated heart perfusion according to Langendorff — Stillviable in the new millennium. Journal of Pharmacological and Toxicological Methods 55 (2007) 113–126 In order to measure intraventricular pressure a fluid-filled balloon...

langendorf heart ADVANTAGES OF ISOLATED HEART PERFUSION • Relatively easy to perform an experiment on intact organ • Cardiac specific effects can be investigated • Used in biochemical, physiological, morphological, pharmacological studies, including drug screening • The controlled environment (buffer, oxygen, pH, temperature) enables high reproducibility of large number of experiments • Pathological circumstances, such as preconditioning, ischemia/reperfusion can be carried out and well controlled DISADVANTAGES OF ISOLATED HEART PERFUSION • Due to the artificial circumstances, less...

At a practical level, the isolated heart, especially from small mammals, provides a highly reproducible preparation which can be studied quickly and in large numbers at relatively low cost. It allows a broad spectrum of biochemical, physiological, morphological and pharmacological indices to be measured (see later). These measurements can be made in the absence of the confounding effects of other organs, the systemic circulation and a host of peripheral complications such as circulating neurohormonal factors. This characteristic may be considered as an investigational advantage in that it...

PARAMETERS WHICH CAN BE MEASURED PARAMETERS WHICH CAN NOT BE MEASURED Left ventricular developed pressure (LVDP) Left ventricular volume (LVV) Left ventricular pressure (LVP) Coronary (aortic) flow Aortic pressure Biphasic action potential (ECG) (“p” wave is mostly absent) Monophasic action potential (MAP pericardial) The Langendorff heart preparation—Reappraisal of its role as a research and teaching model for coronary vasoactive drugs. Original Research Article; Pages 143-156; 2(2):143 (1979), K.J. Broadley http://en.wikipedia.org/wiki/Langendorff_heart Untersuchungen am überlebenden...