Developmental Expression of GABAA Receptor Subunit mRNAs in Individual Hippocampal Neurons In Vitro and In Vivo
Article first published online: 14 NOV 2002
Journal of Neurochemistry
Volume 70, Issue 3, pages 1017–1028, March 1998
How to Cite
Brooks-Kayal, A. R., Jin, H., Price, M. and Dichter, M. A. (1998), Developmental Expression of GABAA Receptor Subunit mRNAs in Individual Hippocampal Neurons In Vitro and In Vivo. Journal of Neurochemistry, 70: 1017–1028. doi: 10.1046/j.1471-4159.1998.70031017.x
- Issue published online: 14 NOV 2002
- Article first published online: 14 NOV 2002
- Received August 1, 1997; revised manuscript received October 22, 1997; accepted October 23, 1997.
- GABAA receptor;
- GABAA receptor subunit mRNA;
- Cell culture;
Abstract: The GABAA receptor is a heterooligomeric protein complex composed of multiple receptor subunits. Developmental changes in the pattern of expression of 11 GABAA receptor subunits in individual rat embryonic hippocampal neurons on days 1–21 in culture and acutely dissociated hippocampal neurons from postnatal day (PND) 5 rat pups were investigated using the technique of single-cell mRNA amplification. We demonstrate that multiple GABAA receptor subunits are expressed within individual hippocampal neurons, with most cells simultaneously expressing α1, α2, α5, β1, and γ2 mRNAs. Further, relative expression of several GABAA receptor subunit mRNAs changes significantly in embryonic hippocampal neurons during in vitro development, with the relative abundance (compared with β-actin) of α1, α5, and γ2 mRNAs increasing 2.3-, 2.7-, and 3.8-fold, respectively, from days 1 to 14, and β1 increasing 5-fold from days 1 to 21. In situ hybridization with antisense digoxigenin-labeled α1, β1, and γ2 RNA probes demonstrates a similar increase in expression of subunit mRNAs as embryonic hippocampal neurons mature in vitro. Relative abundances of α1, β1, and γ2 subunit mRNAs in acutely dissociated PND 5 hippocampal neurons are also significantly greater than in embryonic day 17 neurons on day 1 in vitro and exceed the peak values seen in cultured neurons on days 14–21, suggesting that GABAA receptor subunit mRNA expression within individual hippocampal neurons follows a similar, if somewhat delayed, developmental pattern in vitro compared with in vivo. These findings suggest that embryonic hippocampal neuronal culture provides a useful model in which to study the developmental regulation of GABAA receptor expression and that developmental changes in GABAA receptor subunit expression may underlie some of the differences in functional properties of GABAA receptors in neonatal and mature hippocampal neurons.