Determination of Ca2+-release from the isolated smooth muscle cells in suspension from the guinea-pig ileum.
Collagenase-dispersed cells from the guinea-pig ileum were prepared and Ca2+ release into Ca2+-depleted solution from the isolated single cells obtained by the centrifugation of the dispersed cells on isotonic sucrose solution was determined with a Ca2+-selective electrode. A technique employing an isotonic sucrose solution for washing isolated cells permitted removal of contaminating extracellular fluids and obtaining the isolated cells with minimum loss of cellular Ca2+. The release of Ca2+ from the dispersed cells consisted of at least two phases. The Ca2+ release into an isotonic sucrose-Tris solution (ISTS) was significantly reduced and the early phase of the Ca2+ release disappeared. At 16 degrees C, Ca2+ release depended on the composition of the bathing solution in a Ca2+-free salt solution, the later phase of Ca2+-release was abolished whereas in ISTS both phases disappeared. Furthermore, Ca2+ release was significantly reduced after the treatment of the dispersed cells with disperse (1,500 units/ml) for 10 min. These results show that Ca2+ release into Ca2+-depleted solution from the isolated ileal cells with minimum loss of cellular Ca2+ show a biphasic curve and suggest that Ca2+ sources responsible for these phases may be of distinct origin.
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Science University of Tokyo, Japan.
T
T
Uruno
A
A
Watanabe
K
K
Takahashi
N
N
Sunagane
Y
Y
Matsuoka
K
K
Kubota
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006224:Cricetinae; D003470:Culture Media; D007082:Ileum / Q000378:metabolism; D066298:In Vitro Techniques; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D007477:Ions; D007552:Isotonic Solutions; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D013696:Temperature
D003470:Culture Media; D007461:Iodoacetates; D007477:Ions; D007552:Isotonic Solutions; D012964:Sodium; D002118:Calcium; D019807:Iodoacetic Acid