Modification by magnesium of the excitatory effect of oxytocin in electrical and mechanical activities of pregnant human myometrium. 1990

T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
Department of Obstetrics and Gynecology, Saga Medical School, Japan.

The modification by magnesium of the excitatory effect of oxytocin (10(-5)-10(-2) U/mL) on electrical and mechanical activities of pregnant human myometrium was examined. The excitatory effect of oxytocin was enhanced by external magnesium, and the dose-response curve between oxytocin and relative tension in the presence of 118 mM potassium in tiny muscle strips shifted to the left with increases in magnesium from 0 to 2.4 mM. Oxytocin potentiates spontaneous contractions by enhancing the plateau part of action potentials, and the plateau potential induced in 2.4-mM magnesium was larger than that in magnesium-free solution. In potassium contracture experiments, the muscle contraction was potentiated in accordance with the concentration of preloaded magnesium when 10(-3) U/mL oxytocin was added at the tonic phase. These results suggest that magnesium might primarily potentiate the excitatory effect of oxytocin in electrical and mechanical activities of pregnant human myometrium at superficial sites of the plasma membrane, allowing the possibility of its intracellular action.

UI MeSH Term Description Entries
D008278 Magnesium Sulfate A small colorless crystal used as an anticonvulsant, a cathartic, and an electrolyte replenisher in the treatment of pre-eclampsia and eclampsia. It causes direct inhibition of action potentials in myometrial muscle cells. Excitation and contraction are uncoupled, which decreases the frequency and force of contractions. (From AMA Drug Evaluations Annual, 1992, p1083) Magnesium Sulfate, Heptahydrate,Heptahydrate Magnesium Sulfate,Sulfate, Magnesium
D009215 Myometrium The smooth muscle coat of the uterus, which forms the main mass of the organ. Uterine Muscle,Muscle, Uterine,Muscles, Uterine,Uterine Muscles
D010121 Oxytocin A nonapeptide hormone released from the neurohypophysis (PITUITARY GLAND, POSTERIOR). It differs from VASOPRESSIN by two amino acids at residues 3 and 8. Oxytocin acts on SMOOTH MUSCLE CELLS, such as causing UTERINE CONTRACTIONS and MILK EJECTION. Ocytocin,Pitocin,Syntocinon
D011188 Potassium An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011247 Pregnancy The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH. Gestation,Pregnancies
D004347 Drug Interactions The action of a drug that may affect the activity, metabolism, or toxicity of another drug. Drug Interaction,Interaction, Drug,Interactions, Drug
D005260 Female Females
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000200 Action Potentials Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli. Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D014590 Uterine Contraction Contraction of the UTERINE MUSCLE. Myometrial Contraction,Contraction, Myometrial,Contraction, Uterine,Contractions, Myometrial,Contractions, Uterine,Myometrial Contractions,Uterine Contractions

Related Publications

T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
September 1986, American journal of obstetrics and gynecology,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
January 1990, Gynecologic and obstetric investigation,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
December 1971, The Japanese journal of physiology,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
December 1971, The Japanese journal of physiology,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
December 1985, European journal of obstetrics, gynecology, and reproductive biology,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
December 1968, American journal of obstetrics and gynecology,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
February 1996, Endocrinology,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
February 2016, Anesthesiology,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
April 1990, American journal of obstetrics and gynecology,
T Kawarabayashi, and H Izumi, and M Ikeda, and J Ichihara, and H Sugimori, and K Shirakawa
July 2017, Canadian journal of anaesthesia = Journal canadien d'anesthesie,
Copied contents to your clipboard!