D2-Dopaminergic Agonist Quinpirole and 8-Bromo-Camp have Opposite Effects on Goα Gtp-Binding Protein mRNA without Changing D2 Dopamine Receptor mRNA Levees in Striatal Neurones in Primary Culture

Abstract

Long-term coordinated regulations (during development or by agonists and second messenger molecules) of the expression of mRNAs encoding D2-dopamine (DA) receptors and D2 receptor-linked Goα proteins have been studied by Northern blot analysis in mouse embryonic striatal neurones in primary culture. During the course of the cell culture, the levels of both mRNAs increased, in conjunction with the maturation of the neurones. When the preparation was treated with the D2-DA agonist quinpirole (5–15 hrs, 10⁻⁴ M), which decreases cAMP in these neurones, the levels of Goα mRNAs were enhanced whereas that of the D2 mRNA remained unchanged. Conversely, the Goα mRNAs, but not the D2 mRNA, decreased when the neurones were exposed to 8-bromo-cAMP (16 hrs, 10⁻⁶ M). It is concluded that, in these experimental conditions where neurones have not yet established their connexions, the long-term regulation of the membrane transmission of D2-DA signal might implicate mainly the Goα encoding gene.