Missiaen L, Kanmura Y, Eggermont J A, Casteels R
Laboratorium of Physiology, K.U.Leuven Campus Gasthulsberg, Belgium.
Biochem Biophys Res Commun. 1989 Jan 16;158(1):302-6. doi: 10.1016/s0006-291x(89)80212-8.
In myometrium from pregnant rats, 100 nM-TPA elevated resting tension and initially slightly enhanced the contraction induced by 138 mM-KCl. After 20 min this force development significantly declined. In saponin-treated skinned myometrial cells from pregnant rats, 100 nM-TPA enhanced the contraction induced by 0.3 microM-Ca2+, but reduced that induced by 1 microM-Ca2+. These findings suggest that the excitatory and inhibitory actions of TPA on the myometrium are probably due to its action on the contractile proteins. In myometrium from non-pregnant rats, TPA affected neither the resting tension, nor the amplitude of the evoked contractions, nor the Ca2+-induced contractions in skinned myometrium. While TPA only affected tension development in pregnant rats, both 1 mM-carbachol and 90 nM-oxytocin induced a tonic contraction in Ca-free solution independently of the hormonal status of the rats. The latter finding makes it unlikely that activation of protein kinase C is involved in the agonist-induced tonic force development in Ca-free solution.
在妊娠大鼠的子宫肌层中，100 nM佛波酯可提高静息张力，并在最初略微增强由138 mM氯化钾诱导的收缩。20分钟后，这种力量发展显著下降。在经皂角苷处理的妊娠大鼠子宫肌层皮肤细胞中，100 nM佛波酯增强了由0.3 microM钙离子诱导的收缩，但减弱了由1 microM钙离子诱导的收缩。这些发现表明，佛波酯对子宫肌层的兴奋和抑制作用可能归因于其对收缩蛋白的作用。在未妊娠大鼠的子宫肌层中，佛波酯既不影响静息张力，也不影响诱发收缩的幅度，也不影响皮肤子宫肌层中钙离子诱导的收缩。虽然佛波酯仅影响妊娠大鼠的张力发展，但1 mM卡巴胆碱和90 nM催产素在无钙溶液中均可诱导强直性收缩，且与大鼠的激素状态无关。后一发现表明，蛋白激酶C的激活不太可能参与无钙溶液中激动剂诱导的强直性力量发展。
