Motor activity of the human fallopian tube in vitro in relation to plasma concentration of oestradiol and progesterone, and the influence of noradrenaline

Abstract

The contractile pattern of the human Fallopian tube was studied in preparations from the ampullary and isthmic regions mounted in an organ bath for measurement of longitudinal and circular smooth muscle activity. The material was obtained during the follicular, ovulatory, and luteal phases of the cycle as defined primarily from plasma oestrogen and progesterone values. The frequency of the spontaneous contractions increased progressively during the follicular phase to become maximal around ovulation. There was no consistent difference between isthmus and ampulla; the circular musculature had a higher frequency than the longitudinal during the ovulatory phase. Noradrenaline (3 x 10-6 M) in general potentiated the difference in frequency seen between the ovulatory phase on the one hand and the follicular and luteal phases on the other. Contractile activity, assessed by planimetric integration of the curve on the pen-recorder trace, increased markedly during the ovulatory phase in all types of smooth muscle preparations. Exogenous noradrenaline inhibited spontaneous motor activity in preparations from pregnant or post-menopausal women or from women taking combined-type oral contraceptives. This effect was most marked in the circular muscle. Thus the different regions of the human Fallopian tube in vitro show various patterns of spontaneous motor activity in relation to the plasma steroid concentrations during the menstrual cycle. Responses to exogenous noradrenaline also varied, indicating that the effects of endogenous noradrenaline released from sympathetic nerves may vary similarly.