Upregulation of GABA(A)-receptor alpha 1- and alpha 2-subunit mRNAs following ischemic cortical lesions in rats

Focal cortical lesions are associated with a functional downregulation of t he GABAergic system in perilesional tissue lasting (at least) several weeks . The molecular mechanisms underlying this phenomenon are still poorly unde rstood. Here we used RT-PCR to investigate whether mRNA-levels of two alpha -subunits of the GABA(A)-receptor (alpha 1- and alpha 2-subunits) change fo llowing ischemic cortical lesioning. The results show that 7 days after les ion induction mRNA-levels for both the alpha 1- and alpha 2-subunits are in creased threefold in perilesional tissue ipsilateral, but not contralateral to the lesion. Taken together with the results of a previous immunohistoch emical study in which a moderate decrease of the alpha 1-subunit-protein an d no change for the alpha 2-subunit [T. Neumann-Haefelin, J.F. Staiger, C. Redecker, K. Zilles, J.M. Fritschy, H. Mohler, O.W. Witte, Immunohistochemi cal evidence for dysregulation of the GABAergic system ipsilateral to photo chemically induced cortical infarcts in rats. Neuroscience (Oxford) 87 (4) (1998) 871-879] was observed, this is interpreted as a partial block of tra nslation in the perilesional tissue surrounding cortical ischemic lesions. (C) 1999 Elsevier Science B.V. All rights reserved.