Ca2+-independent contraction of uterine smooth muscle.
Rat uterine smooth muscle shows sustained contraction to oxytocin in Ca2+-free medium with EGTA, that is called "Ca-free contraction"(1). Participation of the rise in cytosolic free Ca2+ in this Ca-free contraction was tested. In Ca-free contraction, the cytosolic free Ca2+ level was not changed at all as measured with fura-2. Further, the chelation of cytosolic free Ca2+ with quin-2 did not at all affect Ca-free contraction. These results strongly suggest that Ca-free contraction is not triggered by Ca2+.
Matsuo
K
K
Department of Molecular Pharmacology, Meiji College of Pharmacy, Tokyo, Japan.
Gokita
T
T
Karibe
H
H
Uchida
M K
MK
D000634:Aminoquinolines; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D003600:Cytosol / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D005260:Female; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D010121:Oxytocin / Q000494:pharmacology; D051381:Rats; D014590:Uterine Contraction / Q000187:drug effects*
D000634:Aminoquinolines; D005456:Fluorescent Dyes; D010121:Oxytocin; D004533:Egtazic Acid; C035739:Quin2; D002118:Calcium