Early expression of GABA(A) receptor delta subunit in the neonatal rat hippocampus.
The cDNA library screening strategy was used to identify the genes encoding for GABA(A) receptor subunits in the rat hippocampus during development. With this technique, genes encoding eleven GABA(A) receptor subunits were identified. The alpha5 subunit was by far the most highly expressed, followed by the gamma2, alpha2 and alpha4 subunits respectively. The expression of the beta2, alpha1, gamma1, beta1 and beta3 subunits was moderate, although that of the alpha3 and delta subunits was weak. In situ hybridization experiments, using digoxigenin-labeled cRNA probes, confirmed that the delta subunit was expressed in the neonatal as well as in the adult hippocampus, and is likely to form functional receptors in association with other subunits of the GABA(A) receptor. When the more sensitive RT-PCR approach was used, the gamma3 subunit was also detected, suggesting that this subunit is present in the hippocampus during development but at low levels of expression. The insertion of the delta subunit into functional GABA(A) receptors may enhance the efficacy of GABA in the immediate postnatal period when this amino acid is still exerting a depolarizing and excitatory action.
Didelon
F
F
Neuroscience Program and Istituto Nazionale Fisica della Materia (INFM) Unit, International School for Advanced Studies (SISSA), Trieste, Italy.
Mladinic'
M
M
Cherubini
E
E
Bradbury
A
A
D000818:Animals; D000831:Animals, Newborn; D006624:Hippocampus / Q000254:growth & development / Q000378:metabolism*; D017403:In Situ Hybridization; D051381:Rats; D011963:Receptors, GABA-A / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D011963:Receptors, GABA-A