Alpha 1b-adrenoceptor-mediated calcium oscillation is specific for the S phase in cell cycle and dependent on the extracellular calcium.
Using Chinese hamster ovary cells stably expressing alpha 1b-adrenoceptor (alpha 1bAR) as a model, we examined the effect of the cell cycle on the agonist-promoted intracellular [Ca2+]i oscillation. In cells synchronized into either the G1 state or the M phase, no oscillatory behavior was observed under any extracellular Ca2+ concentrations ([Ca2+]o < or = 3 mM), whereas in cells synchronized into the S phase, norepinephrine caused [Ca2+]i oscillation in a [Ca2+]o-dependent manner, indicating that alpha 1AR-mediated [Ca2+]i oscillation is specific for the S phase in cell cycle and dependent on [Ca2+]o. The S phase-specific occurrence of alpha 1AR-mediated [Ca2+]i oscillation is not associated with changes in alpha 1AR density. As the cells consistently developed [Ca2+]i oscillation in the S phase, the cells would provide a valuable system to study further the biochemical mechanism for agonist-induced [Ca2+]i oscillation phenomenon.
Awaji
T
T
Department of Molecular Cell Pharmacology, National Children's Medical Research Center, Tokyo, Japan.
Izumi
S
S
Horie
K
K
Hirasawa
A
A
Tsujimoto
G
G
D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology*; D002453:Cell Cycle; D006224:Cricetinae; D007700:Kinetics; D009638:Norepinephrine / Q000494:pharmacology*; D009991:Oscillometry; D018340:Receptors, Adrenergic, alpha-1 / Q000096:biosynthesis / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D016196:S Phase; D013997:Time Factors; D014162:Transfection
D018340:Receptors, Adrenergic, alpha-1; D011994:Recombinant Proteins; D002118:Calcium; D009638:Norepinephrine