Plasma Membrane Density of GABAB-R1a, GABAB-R1b, GABA-R2 and Trimeric G-proteins in the Course of Postnatal Development of Rat Brain Cortex

Abstract

With the aim to understand the onset of expression and developmental profile of plasma membrane (PM) content /density of crucial components of GABAB-R signaling cascade, GABAB-R1a, GABAB-R1b, GABAB-R2, Gi1/Gi2α, Gi3α, Goα, Gzα and Gβ subunit proteins were determined by quantitative immunoblotting and compared in PM isolated from brain cortex of rats of different ages: between postnatal-day-1 (PD1) and 90 (PD90). PM density of GABAB-R1a, GABAB-R2, Gi1/Gi2α, Gi3α, Goα, Gzα and Gβ was high already at birth and further development was reflected in parallel decrease of both GABAB-R1a and GABAB-R2 subunits. The major decrease of GABAB-R1a and GABAB-R2 occurred between the birth and PD15: to 55 % (R1a, **) and 51 % (R2, **), respectively. Contrarily, PM level of the cognate G-proteins Gi1/Gi2α, Gi3α, Goα, Gzα and Gβ was unchanged in the course of the whole postnatal period of brain cortex development. Maturation of GABAB-R cascade was substantially different from ontogenetic profile of prototypical plasma membrane marker, Na, K-ATPase, which was low at birth and further development was reflected in continuous increase of PM density of this enzyme. Major change occurred between the birth and PD25. In adult rats, membrane content of Na, K-ATPase was 3-times higher than around the birth.