Effects of quinine and apamin on the calcium-dependent potassium permeability of mammalian hepatocytes and red cells.

摘要: 1. K-sensitive electrodes placed in the extracellular fluid have been used to show that ATP and noradrenaline cause a rapid loss of up 10% K content isolated guinea-pig hepatocytes. 2. The hypothesis tha this response is consequence rise permeability hepatocyte membrane triggered by an increase cytosolic Ca supported finding divalent cation ionophore A23187 also initiated loss, instance 20-25% amount cells. 3. Under similar conditions caused transient increase, followed larger decrease, 45Ca hepatocytes equilibrated with isotope. decrease alone was seen noradrenaline. 4. Quinine (1 mM) bee venom neurotoxin apamin (10 nM) greatly reduced effect ATP, on without affecting changes movement. 5. Apamin abolished 42K efflux which follows application alpha-adrenoceptor agonist amidephrine rabbit liver slices; concurrent rises glucose release were unaffected. 6. It concluded quinine are able block either Ca-dependent channels present cell membranes or mechanism controls them. 7. Surprisingly, rat took rather than lost when treated concentrations from This ouabain. 8. Application large associated death. 9. influence (10-1000 (200-1000 micro M) red blood cells ghosts studied. even applied both sides ghost membrane, whereas inhibition, as reported others. 10. results suggest carriers rabbit, but lacking inactive liver. blocks not erythrocytes may mean differ these