Studies on the contractility of follicular wall with special reference to the mechanism of ovulation in hens

Abstract

To investigate the mechanism of ovulation in the hen, histological and physiological investigations on the contractility of the follicular wall were carried out. Smooth muscle bundles in the loose connective tissue coat from the stalk to the equator showed spontaneous rhythmic contractions with an alternation of contraction and pausing periods of about 4 min. The administration of prostaglandins F2 alpha (PGF2 alpha), E2 (PGE2), ovarian oviposition inducing factor (OOIF), oxytocin and acetylcholine increased the frequency and amplitude of the contractions. The theca layer showed spontaneous contractions at a frequency of about 30 per 10 min. PGF2 alpha, OOIF, acetylcholine, adrenaline and noradrenaline induced tonic contractions, whereas PGE2, oxytocin and histamine induced relaxation. It is suggested that the contraction of the follicular wall promotes the rupture of the stigma at ovulation and the neurotransmitters as well as prostaglandins and OOIF may be involved in this event.

In Vitro Study of the Contractility of the Wall of the Preovulatory Follicle in the Japanese Quail1

“…They observed that isolated longitudinal strips of the F of White Leghorn hens exhibit spontaneous contractions and showed that spontaneous and induced contractions depend on the maturation stage of the follicle. Yoshimura et al [15], using the F. and the next largest follicle (F 2 ) of laying hens, also observed the occurrence of spontaneous contractions in longitudinal and transverse strips of the follicular wall. In the exterior part of the wall (tunica superficialis and tunica albuginea and surface epithelium), they reported that spontaneous contractions of longitudinal strips are characterized by a high-amplitude, rhythmic pattern, whereas transverse strips have an irregular frequency and low amplitude.…”

“…This difference can be explained by the presence of longitudinal running branches of chordae in the longitudinal strips. Yoshimura et al [15] suggested that the follicular wall near the time of ovulation shows a high contractile activity.…”

“…Bartelmez [13] has reported that the pigeon oocyte is squeezed out of the F mainly by the rapidly contracting wall. Spontaneous contractile activity is found in strips of the wall of the F [14,15]. It is suggested that contractile activity of the ovarian chordae creates a flow of peritoneal fluid from the peritoneal cavity into the ovarian lacunae [16].…”

Oogenesis and ovarian histology of the American alligatorAlligator mississippiensis

“…In the birds studied above, the muscle fibers are interconnected, forming an ovarian suspensory apparatus. Yoshimura et al (1983) suggested that near the time of ovulation the hen's follicular wall exhibits elevated levels of contractile activity contributing to follicular rupture. Several roles have been suggested for this contractile ability.…”

Influence of Vasotocin and Isoproterenol on the In Vitro Motility of the Follicular Stalks and Infundibulum in the Domestic Hen

“…In the fowl ovulation and engulfment of the shed ovum by the infundibulum must be well-coordinated to initiate the transport of the egg through the oviduct. The contractions of the follicular wall and stalks are important in the ovulatory process in hens (19). As shown by these authors the follicular wall has two types of contractile cells: smooth muscle cells in the loose connective tissue derived from the stalk and theca fibroblast-like cells.…”