In vitro study of the contractility of the wall of the preovulatory follicle in the Japanese quail.
In the present study, we examined in vitro the potassium-induced contractions of isolated parts of the wall of the quail preovulatory follicle through use of an electromagnetic force-length transducer system. We studied longitudinal and transverse strips of the whole wall, of the theca, and of the outer layer (tunica albuginea and surface epithelium). It was observed that force development and shortening of strips of the whole wall and those of the theca are similar. Statistical analysis of maximal isometric force, peak shortening length, and percentage of reduction of follicular volume showed that the orientation of strips is without importance. Results from different orientations were pooled, and the different layers were compared statistically. The general result of this analysis was that the contractile activity of the outer layer was significantly lower than the performance of either the whole wall or the theca. We concluded that contraction of the follicular wall is mainly dependent on the contractile activity of the theca externa. This contractile system is comparable to that of mammals. We suggest that the main function of the theca externa during ovulation is to maintain a constant intrafollicular pressure.
Laboratory of Human Anatomy and Embryology, University Centre of Antwerp, Belgium.
L
L
Van Nassauw
S U
SU
Sys
F
F
Harrisson
M
M
Callebaut
D000818:Animals; D003370:Coturnix / Q000502:physiology*; D055590:Electromagnetic Phenomena; D005260:Female; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000502:physiology; D011188:Potassium / Q000494:pharmacology; D014159:Transducers
D011188:Potassium