Intracellular calcium of longitudinal muscles isolated from pregnant rat myometrium.
Longitudinal muscle cells were successfully isolated from pregnant rat myometrium (21 days of gestation) with more than a 95% survival rate. The approximate size of relaxed cells was 232.2 +/- 74 microns in length and 16.2 +/- 7.0 microns in width. Using the fluorescent indicator Fura-2, the concentration of intracellular free calcium ([Ca2+]i) in resting state cells was calculated to be 116 +/- 18.5 nM. The isolated cells responded well to K+, acetylcholine and oxytocin in terms of contraction as well as the increase in [Ca2+]i. The increase in [Ca2+]i induced by acetylcholine and K+ appeared to be mainly due to an influx of extracellular Ca2+. On the other hand, the oxytocin-induced increase in [Ca2+]i was mainly due to a release of Ca2+ from intracellular storage sites in the isolated cells. Isolated longitudinal muscle cells can serve as a useful tool in establishing the relationship between [Ca2+]i and regulation of the uterine contraction at the final stage of pregnancy.
Tsukamoto
T
T
Department of Applied Biological Sciences, Saga University, Japan.
Kawarabayashi
T
T
Kaneko
Y
Y
Kumamoto
T
T
Sugimori
H
H
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D002469:Cell Separation; D005260:Female; D016257:Fura-2; D009215:Myometrium / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D010121:Oxytocin / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D014590:Uterine Contraction / Q000187:drug effects
D010121:Oxytocin; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium; D016257:Fura-2