The effect of adrenaline on the electrogenic Na+ pump in cardiac muscle cells.
Electrogenic Na+ pump currents during K+-activated hyperpolarizations of bullfrog atrium muscle fibres are increased by adrenaline. The log dose-response relation between these currents and activating K+ concentrations is expressed by a sigmoidal curve, which is shifted in parallel to the left by adrenaline. It is suggested that adrenaline increases the rate of Na+ extrusion without increasing the Na/K coupling ratio and total number of pumping sites.
D000818:Animals; D001001:Anura; D004837:Epinephrine / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*
D012964:Sodium; D011188:Potassium; D004837:Epinephrine