Steroid cardiac

Cardiac depressant Cardiac steroids Cardigin Car dilate Cardinal Clear Carding... 

Other stmctural variations in both series are the stereochemistry at C3 and the degree of oxidation on the nucleus and side chains. Cardiac steroids probably exert their inotropic effects by acting as specific, noncompetitive inhibitors of — ATPases, known as sodium pumps, and thus... 

Cardiac steroids occur ia small amounts ia various plants with a wide geographical distribution. The purple foxglove Di talispurpurus has been used for centuries as both a dmg and a poison. Isolation and characterization of the various cardiac steroids have been reviewed (122,123). 

Application of this tandem conjugate addition-aldol cyclization methodology may lead to the concise synthesis of digitoxin (Scheme 67) and related cardiac steroids. 

Myocardial cell membrane ATPase, the enzyme present in heart muscle, is the site of action of the cardiac steroid glycosides, which have a specific action on the heart muscle. These drugs increase the force of contraction of the muscle (positive inotropic effect) as well as its conductivity and automaticity. They are also valuable in treating congestive heart failure, in which the circulatory needs of organs are no longer satisfied, and heart arrhythmias, in which the rhythm of the cardiac contractions is upset. The effect of the drug is that the force of contraction increases and the heart rate is slowed (chronotropic effect). Consequently, the cardiac output is elevated while the size of the heart decreases. 

The exterior of the myocardial enzyme, situated in the plasmalemma, is considered to be the specific binding site of cardiac steroid glycosides. It is believed that the positive inotropic effect is due to the inhibition of enzyme dephosphorylation and... 

Cardiac steroids, or cardenoUdes, are steroid glycosides. Their effect has been known since the time of the ancient Egyptians. In more recent times, the foxglove (Digitalis purpurea) and its effect were described in 1785 by William Withering, who knew of its use in folk medicine. 

Direct Isolation. The two most important classes of steroid pharmaceuticals that are isolated directly from natural products are some estrogens and most cardiac steroids. Compounds with estrogenic activity have been isolated from different sources, including urine from pregnant women and from pregnant marcs. Cardiac steroids occur in small amounts in various plants with a wide geographical distribution. 

Interestingly, eleetron mieroseopie studies has provided an ample evidenee that the a-dimer usually creates a deep-cleft in the Na, K -ATPase and that has been suggested as the most preferred binding site for the cardiac steroidal glycosides particularly. 

Describe any two of the following cardiac steroids and inotropic drugs ... 

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