Possible Interaction: Cardiac Glycosides and Norepinephrine

“In the presence of the glycoside , the responses to noradrenaline and potassium are potentiated.”

“In the constant flow perfused rat hind limb, norepinephrine (NE) evoked increases in oxygen uptake (VO2) and lactate efflux (LE) were inhibited by the cardiac glycoside ouabain (1 mM), without interrupting the NE-mediated vasoconstriction.”

“ Cardiac glycosides prevent the predominance of the beta-adrenergic effects of norepinephrine.”

“On the other …, all the cardiotonic steroids at concentration of 2 X 10(-5) M … inhibited the reuptake of K and relaxation of norepinephrine-induced contractions induced by the readdition of K. Inhibition of Na-K pump by K-free solution potentiated rather than inhibited the PTX-induced contraction.”

“ C.G. cause the release of noradrenaline , acetylcholine, or prostaglandins.”

“ Cardiac glycosides such as ouabain inhibit Na+-dependent high-affinity noradrenaline uptake in sympathetic nerve terminals by interacting with (Na++K+)ATPase located in the neuronal membrane1–3.”

“Plasma concentrations of H3-norepinephrine were significantly higher after ouabain, and the glycoside appeared to inhibit the uptake of H3-norepinephrine by the heart.”

“The glycoside acutely reduced the myocardial store of adrenaline and noradrenaline in normal rabbits.”

“Lowering the body temperature of normal dogs modifies the contractile response of the heart to norepinephrine , and this modified response is in turn drastically influenced by the administration of a cardiac glycoside during hypothermia (28-30°).”