Ionic fluxes in rat uterine smooth muscle.
1. The K+, Na+ and Cl-fluxes from the oestrogen-stimulated rat uterine smooth muscle were measured using radioactive tracers. 2. The cellular compartment contained a concentration of K+ of 173-6 mM which exchanged at a rate of 5-9 x 10(-12) mol.cm-2.sec-1. 3. Cl- exchanged at a rate of 6-9 x 10(-12) mol.cm-2.sec-1 from a cellular compartment having a concentration of 39-3 mM. 4. The methods used for the evaluation of Na+ movements over-estimate both influx and efflux values. If an average value of flux of 9-2 x 10(-12) mol.cm-2.sec-1 is considered we obtain PNa+/PK+ ratios of 2-4 (-42 mV) or 1-3 (-57-6 mV), which are too high and do not correspond to electrophysiological evidence. 5. The relative permeabilities PCl-/PK+ in the case of a membrane potential of -42-0 mV could be 0-8, or 1-3 in the case of a membrane potential of -57-6 mV. 6. Both conductances GK+ and GCl- seem to play an important role in determining membrane conductance.
D000818:Animals; D002463:Cell Membrane Permeability; D002712:Chlorides / Q000378:metabolism*; D005260:Female; D008564:Membrane Potentials; D009130:Muscle, Smooth / Q000378:metabolism*; D009215:Myometrium / Q000378:metabolism / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*
D002712:Chlorides; D012964:Sodium; D011188:Potassium