Abstract |
The circular muscle strips were isolated from rat uterus 10-60 h after parturition, and the electrical and mechanical responses were investigated. The muscle strips exhibited a variety of contractile activity ranging from frequent spontaneous contractions generated on an elevated muscle tone to a sustained contracture, when incubated with Mg-free Krebs solution. The muscle tone was lowered, and phasic contractions were abolished when the external Ca was removed. Muscle tone was also lowered by addition of 1.2 mM Mg, 1 mM spermidine, or 1 mM tetracaine. The membrane potential was about -25 mV in a muscle which exhibited a contracture, and the membrane was hyperpolarized by 20-25 mV by the (1.5-4.5 x 10(-5) M) caused a gradual decrease in muscle tone, and the that Ca-influx was increased, for which prostaglandin(s) was membrane was hyperpolarized. In view of the above results, it is hypothesized that Ca-influx was increased, for which prostaglandin(s) was probably responsible, in the circular muscle of postpartum rat uterus, thereby elevating the muscle tone in Mg-free solution.
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Authors | T Osa, K Maruta |
Journal | The Japanese journal of physiology
(Jpn J Physiol)
Vol. 38
Issue 3
Pg. 329-44
( 1988)
ISSN: 0021-521X [Print] Japan |
PMID | 3184560
(Publication Type: Journal Article)
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Chemical References |
- Isotonic Solutions
- Krebs-Ringer solution
- Tetracaine
- Magnesium
- Calcium
- Spermidine
- Indomethacin
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Topics |
- Animals
- Calcium
(metabolism)
- Female
- Indomethacin
(pharmacology)
- Isotonic Solutions
(pharmacology)
- Magnesium
(pharmacology)
- Muscle, Smooth
(physiology)
- Postpartum Period
- Pregnancy
- Rats
- Spermidine
(pharmacology)
- Tetracaine
(pharmacology)
- Uterine Contraction
(drug effects)
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