Effects of glucocorticoid on brain acetylcholinesterase of developing chick embryos

Abstract

The cerebrum, cerebellum and optic lobe of chick embryos could be influenced by glucocorticoids because of the presence of glucocorticoid receptor mRNA. Although the effects observed after treatment with excess glucocorticoids (even no effects after mifepristone treatment) were transitory, they may alter the developmental program in ways that could result in lasting change and influence behavioral activities after hatching.

Effect of antithyroid drug on chick embryos during the last week of development: Delayed hatching and decreased cerebellar acetylcholinesterase activity

“…Preparing and caring for fertilized eggs was carried out as previously described 18,19 . Fertilized white Leghorn chicken eggs were purchased from a local hatchery and placed in an incubator at approximately 12.00 hours on day 1.…”

“…The wet weights were determined and the specimens were stored at −80°C until further use. AChE activities in the telencephalon, cerebellum and optic lobe were assayed by the method described in a previous paper 18 . Briefly, the supernatant obtained after the homogenates were centrifuged at 10 000 rpm for 5 min at 4°C was used to determine AChE activities.…”

“…RT–PCR was conducted with a Taqman Gene Expression assay kit to detect transcript levels of THR β (NM205447). The data were analyzed by AB 7500 Sequence Detection Systems software version 1.4 as previously described 18 . The relative expression level for each target gene was normalized to the Ct value of chick GAPDH (NM205447) (2 ΔCt formula, Perkin Elmer User Bulletin #2).…”

“…Preparing and caring for fertilized eggs was carried out as previously described. 18,19 Fertilized white Leghorn chicken eggs were purchased from a local hatchery and placed in an incubator at approximately 12.00 hours on day 1. Incubation was carried out at 37.5°C and 68% relative humidity, with rocking through a range of 30 degrees in a 30-min cycle.…”

Hormones and Cerebellar Development

“…Expression is first detected in the embryonic rat brain, and levels are high and similar in the developing cerebellum and hippocampus (Lawson et al 1992). Prenatal glucocorticoids influence the development of Purkinje neurons (Rugerio-Vargas et al 2007) and a recent study using chick embryos has reported the presence of GR mRNA in the embryonic cerebellum (Yamate et al 2010). Furthermore, Yamate et al also showed that effects after treatment with excess glucocorticoids are mediated via GRs and indirectly influence behavioral activity after hatching.…”