[Catecholamines--therapeutic and adverse effects on the heart].
Catecholamine activation enhances the inotropy of the heart by increasing the sarcolemmal influx of Ca2+. This increased influx is counteracted by an increased sarcolemmal efflux and sarcoplasmic reticulum uptake of Ca2+. Thus the intracellular milieu is protected against a gradual rise in Ca2+ concentration. However, under conditions of continuous, excessive catecholamine release, the heart's potential to remove Ca2+ from the cytosol might become exhausted. This might be caused by a Ca2+-dependent exhaustion of high-energy phosphates. As a result of this, Ca2+ overload of the myocytes and eventually a decrease in the pump function of the heart might occur. This paradox has implications for the clinical management of ischaemic heart disease.
Steinmann
C M
CM
Departement Geneeskundige Fisiologie en Biochemie, Universiteit van Stellenbosch, Parowvallei, KP.
D015220:Calcium Channels / Q000502:physiology; D002395:Catecholamines / Q000502:physiology*; D006801:Humans; D009206:Myocardium / Q000378:metabolism*; D012508:Sarcolemma / Q000502:physiology
D015220:Calcium Channels; D002395:Catecholamines
Katesjolamiene--beskermers en beskadigers van die hart.