Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sodium azide is a strong inhibitor of the tonic component of contraction produced by oxytocin, whereas aminophylline produces almost equal inhibition of all types of activation of the isolated rat uterus. Both substances inhibited the spontaneous rhythmic activity of the uterus. The effect of sodium azide is easily reversed by calcium. The results are taken to indicate a complex relation between calcium and substances which stimulate metabolism either of cGMP (sodium azide) or cAMP (aminophylline) in producing relaxation of the isolated rat uterus.
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PMID:Comparative effects of sodium azide and aminophylline on the rat isolated uterus during muscle activation. 286 67

Sodium azide (NaN3) and dinitrophenol (DNP) at low concentrations caused "Ca reversal", i.e. inhibition of oxytocin-induced tonic contraction of estrogen-dominated rat uterine smooth muscle in Ca-free solution. This inhibition was not due to depletion of ATP by NaN3 or DNP. Higher concentrations of NaN3 and DNP caused additional contraction. NaN3 and DNP dose-dependently released Ca ion from mitochondria isolated from the estrogen-dominated rat uterine smooth muscle in vitro. Electron microscopic studies have shown that in estrogen-dominated rat uterine smooth muscle cells, cytoplasmic membranes proliferate, resulting in compartmentalization of the myofilament-sarcoplasmic system and its separation from the receptor-effector system in the surface folds of the plasma membranes, which also contain some mitochondria. It is proposed that low concentrations of NaN3 and DNP release a small amount of Ca ion from these outer mitochondria and this Ca ion acts on the intracellular "site of Ca reversal" to induce reversal, i.e. inhibition. Higher concentrations of NaN3 and DNP are proposed to release a large amount of Ca ion from the central mitochondria near myofilaments and so induce contraction. The "site of Ca reversal" was shown to be intracellular as our previous postulation.
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PMID:Intracellular site of "Ca reversal": inhibition of uterine smooth muscle contraction in Ca-free medium by a minute amount of Ca ion released from mitochondria by drugs. 369 40