[Effect of divalent metal ions--stimulants of uterine contractile activity--on the Mg2+, ATP-dependent transport of Ca2+ in the myometrial sarcolemma fraction].
Mn2+, Co2+, Zn2+ and Cu2+ were shown to inhibit the Mg2+-ATP-dependent accumulation of 45Ca2+ in the fraction of cytoplasmic membranes. Mechanism of inhibitory effect of the Me2+ is considered. It is assumed that the cations, exhibiting higher affinity to ATP as compared with Mg2+, contributed to dissociation of the actual substrate of the enzymatic reaction Mg2+-ATP as well as to formation of the chelate complexes of the Me2+-ATP type; these complexes participated in the transport of Ca2+ less effectively as compared with the true substrate Mg2+-ATP. Among the essential factors responsible for an increase in the contractile activity of uterus in response to divalent ions of metals, accumulated into cells, elevation of Ca2+ concentration appears to occur in myocytes due to inhibition of the Mg2+-ATP-dependent output of Ca2+ from myoplasm into interstitial space.
Kosterin
S A
SA
Kurskiĭ
M D
MD
Bratkova
N F
NF
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002413:Cations, Divalent; D002417:Cattle; D005260:Female; D066298:In Vitro Techniques; D008274:Magnesium / Q000378:metabolism*; D008670:Metals / Q000494:pharmacology*; D009215:Myometrium / Q000187:drug effects* / Q000378:metabolism; D012508:Sarcolemma / Q000187:drug effects / Q000378:metabolism; D013268:Stimulation, Chemical; D014590:Uterine Contraction / Q000187:drug effects*
D002413:Cations, Divalent; D008670:Metals; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium
Vliianie dvukhvalentnykh ionov metallov--stimuliatorov sokratitel'noĭaktivnosti matki na Mg2+, ATF-zavisimyĭ transport Ca2+ vo fraktsii sarkolemmy miometriia.