Ei Terasawa

Modulating Effect of Limbic Structures on Gonadotropin Release

Serum and pituitary LH and FSH were measured during the estrous cycle, following electrical stimulation of the medial preoptic area (MPO), medial part of the amygdala (AMYG), and dorsal hippocampus (H

Changes in Multiunit Electrical Activity (MUA) in Rat Brain During the Estrous Cycle and After Administration of Sex Steroids

Publisher Summary This chapter describes the observed changes in multiunit activity (MUA) in several brain regions during the estrous cycle and/or after administration of sex hormone to the rat. An attempt is made in the discussion to correlate these changes with cyclic gonadotrophin secretion and ovulation in this species. Injection of estrogen on the day of diestrus I advance the evening rise of MUA in these regions by one day. The increase of MUA after estrogen administration appears to correspond to the facilitatory effect of estrogen on gonadotrophin secretion. The septal complex appears to act primarily as a site of the feedback action of estrogen whereas medial preoptic region (MPO), arcuate nucleus (ARC) and periventricular preoptic area (PVA) constitute the central integrative mechanism responsible for the cyclic release of gonadotrophin. The lowest level of the basal MUA in this brain region, particularly the medial prechiasmatic area, was observed from the evening of the day of estrus through the day of diestrus I.

Correlated Changes in Gonadotropin Release and Electrical Activity of the Hypothalamus Induced by Electrical Stimulation of the Hippocampus in Immature and Mature Rats

For the past forty years, attention has been focussed on the limbic structure implicated in gonadal function and sexual behaviour. Kluver and Bucy (1937), Schreiner and Kling (1953) and Green et al. (1957) demonstrated hypersexual behaviour in the monkey and cat with ablations of the pyriform cortex or amygdala, and MacLean (1957a, b) reported intensive grooming and penile erection following the after-discharges induced by electrical stimulation of the hippocampus in the rat, cat and monkey.