[Modulation of calcium sensitivity in the heart muscle--physiology, pathophysiology and pharmacology].
Angiotensin II has a plethora of different actions in the heart including, for instance, also slight positive inotropic effects. Thus cardiotonic therapy with angiotensin converting enzyme (ACE) inhibitors should possibly be complemented by positive inotropic drug therapy. With this respect, novel cardiotonic drugs that increase calcium sensitivity of myofilaments such as pimobendan (CAS 118428-36-7) might be particularly useful, as they will increase force with little, if any concomitant increase in myoplasmic free calcium. These drugs mimic mechanistically the Frank-Starling-Mechanism or alpha-adrenergic effects which also involve, at least partly, calcium sensitization of the myofilaments. The latter may therefore be a useful therapeutic principle, in particular in cases where myofibrillar calcium responsiveness is pathologically depressed such as for instance in the stunned myocardium or under hypoxic conditions.
II. Physiologisches Institut, Universität Heidelberg.
J C
JC
Rüegg
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects*; D006321:Heart / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D006801:Humans; D009206:Myocardium / Q000378:metabolism*
D015220:Calcium Channels; D002118:Calcium