AJP - Regulatory, Integrative and Comparative Physiology, Vol 252, Issue 6 1059-R1065, Copyright © 1987 by American Physiological Society
Changes in physiological properties of rabbit oviduct by ovarian steroids
M. Nozaki and Y. Ito
Effects of estrogen and progesterone on electrical and mechanical
properties of longitudinal smooth muscle cells of the rabbit fallopian
tubes were investigated using microelectrode and isometric tension
recording methods. In tissues from the estrogen-treated rabbits, there was
a decrease in frequency of spontaneous contractions, whereas an increase
was seen in tissues from the progesterone-treated rabbits. The membrane
potential of smooth muscle cells of the fallopian tube was -58.5 mV.
Following treatment with progesterone or estrogen, the membrane was either
depolarized (-53.7 mV, P less than 0.05) or hyperpolarized (-63.2 mV, P
less than 0.05), respectively. Spontaneous burst discharges were recorded
from these smooth muscle cells, and changes in the frequency of the bursts
induced by treatment with progesterone or estrogen corresponded well with
changes in the spontaneous contractions. Passive electrical parameters such
as the time and space constants were increased by treatment with
progesterone and decreased by treatment with estrogen. Therefore endogenous
ovarian steroids probably participate in transport of the ovum by
controlling spontaneous membrane and mechanical activities of the smooth
muscle cells of the fallopian tube.
