Isolation of Rat Telencephalic Neural Explants to Assay Shh GABAergic Interneuron Differentiation-Inducing Activity

Abstract

Multiple assays for Shh activity using cell lines, primary cultures, and explanted tissue have been described. We first described the use of E11.5 rat dorsal telencephalic explants to assay Shh ventralizing and differentiation-inducing activity in Kohtz et al. (1). Using this assay, we subsequently showed that N-lipid modification is critical for Shh activity in the telencephalon (2). In vivo assays for lipid-modified Shh support the results of our E11.5 telencephalic neural explant assay (2). More recently, the method of isolating telencephaic explants was improved by an intraocular grid, increasing both its accuracy and reproducibility (3). Shh induces the expression of the following ventral telencephalic markers: MASH-1, the Dlx's, and Islet 1/2. Therefore, this assay for Shh induction of GABAergic interneurons defines a competent, but naïve region within the E11.5 dorsal telencephalon, allowing the study of GABAergic interneuron induction and differentiation from an unspecified progenitor population.

Prenatal caffeine intake differently affects synaptic proteins during fetal brain development

“…Our results are also in line with in vitro studies in which caffeine at relatively high concentrations promoted an overexpression of Shh cultured neurons and astrocytes (Sahir et al, 2004). Importantly, Shh is related to induction of GABAergic interneuron differentiation in telencephalon at early embryonic stages (E11.5) (Mady and Kohtz, 2007). One of the consequences of increasing this morphogen in late pregnancy might be an abnormal distribution of neurons in cortical layers before birth, which may impact GABA neuron migration postnatally.…”