Ca2+-inhibition of Ca2+-induced small contraction of rat uterine smooth muscle
| Autor: | Yuuki Miyauchi, Masaatsu K. Uchida |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
medicine.medical_specialty
Cytochalasin D Indoles Contraction (grammar) Vasodilator Agents Carbazoles chemistry.chemical_element Calcium Biology Oxytocin Inhibitory postsynaptic potential Uterine Contraction Alkaloids Calmodulin Internal medicine medicine Animals Drug Interactions Myosin-Light-Chain Kinase Actin Pharmacology Sulfonamides Myometrium Muscle Smooth biology.organism_classification Actina Actins Rats Endocrinology chemistry Female medicine.symptom medicine.drug Muscle contraction |
| Zdroj: | European Journal of Pharmacology. 263:75-80 |
| ISSN: | 0014-2999 |
| DOI: | 10.1016/0014-2999(94)90525-8 |
| Popis: | Ca2+ has been reported to exert an inhibitory effect on various kinds of smooth muscle. The physiological role of this inhibition is unclear. We investigated the inhibitory action of Ca2+ on the uterine smooth muscle of the rat in estrus, which shows a prominent Ca(2+)-induced inhibition. At concentrations of 0.1-30 microM Ca2+ inhibited the Ca(2+)-independent contraction of this muscle induced by oxytocin in Ca(2+)-free medium. We then investigated the inhibitory action of Ca2+ at various concentrations of Ca2+ in the bathing medium and found that Ca2+ at 1.0-10 microM also inhibited Ca(2+)-dependent contractions, which appeared phasically upon the onset of contractions. The magnitude of these phasic contractions was inversely proportional to the concentration of Ca2+ (between 1-10 microM). At 30 microM Ca2+, however, this inhibition was overcome and large pendular contractions began. Thus, the inhibition may regulate the initiation of smooth muscle contractions. The mechanism of this Ca(2+)-induced inhibition is also discussed with regard to an effect on actin. |
| Databáze: | OpenAIRE |
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