title: The influx of calcium ions into human erythrocytes during cold storage.
abstract: 1. When human erythrocytes, suspended in iso-osmotic sucrose containing CaCl(2), are stored at 3 degrees C, Ca(2+) influx into the cells occurs. Simultaneously, efflux of K(+), Na(+), Cl(-) and water takes place and cell volume diminishes. 2. The extent of Ca(2+) influx increases with duration of cold storage and with increasing concentration of Ca(2+) in the suspending medium. 3. Erythrocytes that have been thus loaded with Ca(2+) exhibit Ca(2+) efflux against a concentration gradient when subsequently incubated at 37 degrees C. 4. Ca(2+) influx likewise occurs when the sucrose of the medium is replaced by iso-osmotic solutions of other non-ionized compounds. 5. Replacement of sucrose by iso-osmotic KCl or NaCl greatly diminishes the rate of Ca(2+) influx during cold storage; however, in iso-osmotic choline chloride, Ca(2+) influx is as rapid as in sucrose. 6. Preincubation of erythrocytes in iso-osmotic sucrose at 37 degrees C causes rapid efflux of K(+) and Na(+) and renders the cell membranes highly permeable to Ca(2+) during subsequent cold storage. 7. Preincubation of erythrocytes in iso-osmotic NaCl at 37 degrees C with trypsin or neuraminidase is without effect on the permeability of the membrane towards Ca(2+). 8. The experimental results lead to the conclusion that the main prerequisite for Ca(2+) influx into erythrocytes is the partial depletion of the cells of their univalent cations.
mesh_terms: D001692:Biological Transport; D002118:Calcium / Q000097:blood*; D002712:Chlorides / Q000378:metabolism; D003080:Cold Temperature; D004355:Drug Stability; D004912:Erythrocytes / Q000378:metabolism*; D006461:Hemolysis; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D009439:Neuraminidase; D011188:Potassium / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013054:Spectrophotometry, Atomic; D013395:Sucrose; D013997:Time Factors; D014357:Trypsin
chemical_list: D002712:Chlorides; D012965:Sodium Chloride; D013395:Sucrose; D011189:Potassium Chloride; D012964:Sodium; D009439:Neuraminidase; D014357:Trypsin; D008274:Magnesium; D011188:Potassium; D002118:Calcium