家兎子宮に及ぼす2, 3収縮剤の影響
特に子宮筋電図および機械曲線について
1966 年 26 巻 11 号 p. 700-719
詳細
1966 年 26 巻 11 号 p. 700-719
The electrical activity of rabbit uterus and vagina has been recorded by the small calomel or implanted platinum electrodes.
Estrogen dominated uterus showed very active contractions and the configulation of action potentials were very spiky. The effective concentration of drugs were 50μU/kg in Oxytocin, 1μg/kg in Methergin and 0.5 mg/kg in Spatym. The corpus portion produced the maximum tension and the cervical portion showed repetitive contractions by the application of drugs but the activity was decreasedby progesteron.
The pace-maker region of vagina has not been determined but usually contraction waves initiated at the cervical end and traveles down to the olificed end, but the visible contraction rings became strongest at the middle portion. The conduction velocity of the impulse was about 2.1-3.9 mm/sec at the cervical and 1.3-3.0 mm/sec at the middle portion. The action potential consists fast RQ waves which were superimposed by spike train and a slow T wave. Automatic contractions were easily evoked by distention of vaginal muscle. Usually the ovariectomized rabbit vagina did not contracts spontaneously, but when the inner pressure of vagina was increased to about 5-10 mmHg, the contraction was elicited frequently and the impulses were conducted down to the olifice. When the muscle was distended about 10-15 mmHg inner pressure, the train discharge were recorded and the initiation of automatic contraction became more frequently and more stronger. But when the pressure was increased to 20-30 mmHg, the muscle distended so strong that the muscle could not contracts, evenso the brief train of spike discharge could be observed. The rhythmic contractions were also observed from the isolated vaginal muscle and the activity of muscle was increased by drugs such as Methergin. When adrenaline was given -0.03 mg/kg- a conduction was blocked and asynchronized electrical activity was generated at different vaginal portion. The same action of acetylcholine was weaker than that of adrenaline. As uterine muscle, the activity of vaginal muscle was strongly controled by hormonal status.
