Cholinesterase in the Diencephalon of the Hen in Relation to Egg Laying

Abstract

THE involvement of a neural component in the mechanism of ovulation in the hen was demonstrated by the blockade of ovulation with adrenolytic and para-sympatholytic drugs (Zarrow and Bastian, 1953) or oviducal irritation (Huston and Nalbandov, 1953; van Tienhoven, 1953), and by the stimulation of ovulation with certain barbiturates (Fraps and Case, 1953). Fraps (1954) postulated that the neural component had a diurnal periodicity in the threshold level of excitation for discharge of LH to cause ovulation.Premature oviposition with a para-sympathomimetic drug (Weiss and Sturkie, 1952) or the irritation of uterus by a loop of thread (Sykes, 1953), and delayed oviposition with sympathomimetic drugs (Weiss and Sturkie, 1952; Sykes, 1955) suggest the involvement of nervous factors in the regulation of oviposition in the hen, although it remains undetermined whether the nervous factors act on the uterus directly or through the release of posterior pituitary hormones which in turn cause …