Quantitative reverse transcription-polymerase chain reaction of GABA A α 1, β 1 and γ 2S subunits in epileptic rats following photothrombotic infarction of neocortex

• Published in: Epilepsy research Vol. 52; no. 2; pp. 85 - 95
• Main Authors: Liu, Jiangping, Schmitt, Kathy L, Kharlamov, Elena A, Stolarski, Carol J, Grayson, Dennis R, Kelly, Kevin M
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2002
• Subjects: GABA A receptor subunits; Infarction; mRNA; Photothrombosis; poststroke epilepsy; RT-PCR; GABA A receptor subunits; RT-PCR; poststroke epilepsy; Infarction; mRNA; Photothrombosis
• ISSN: 0920-1211; 1872-6844
• DOI: 10.1016/S0920-1211(02)00194-8

Photothrombotic brain infarction can result in altered expression of cortical GABA A receptors and in epileptic seizures. We sought to determine whether infarct size and/or epileptic seizures resulted in a differential expression of cortical GABA A receptor subunit mRNA in adult rats. A reverse transcription-polymerase chain reaction (RT-PCR) was used with internal standards for GABA A receptor subunits to quantify α 1, β 1, and γ 2S subunit mRNA expression in cortex ipsilateral and contralateral to left cerebral infarcts in small or large infarct/nonepileptic cohorts, a large infarct/epileptic cohort, and a young adult control cohort. Unilateral hemispheric subunit mRNA was pooled for each cohort, quantified, and expressed as mean values±S.E.M. In general, the magnitude of mRNA expression (pg/1 μg total RNA) was different for the individual subunits: γ 2S (10 4), α 1 (10 2), and β 1 (10 1). Hemispheric subunit mRNA expression for the different cohorts was compared by ANOVA testing, which noted significant differences for the α 1 ( P<0.001) and β 1 ( P<0.001) subunits in ipsilateral cortex. Bonferroni post-testing for α 1 cohorts indicated that mRNA expression for the large infarct/epilepsy cohort (624.2±6.8 pg) was greater than all other cohorts ( P<0.001); control (162.7±32.2 pg). For β 1 cohorts, there was decreased mRNA expression in the large infarct/nonepileptic cohort (9.2±0.8 pg; P<0.01) and the large infarct/epileptic cohort (10.5±2.2 pg; P<0.05) compared to control (23.2±2.6 pg). Additionally, paired t-tests compared subunit mRNA expression within individual animal cohorts (ipsilateral vs. contralateral) and indicated decreased mRNA expression ipsilaterally for the β 1 subunit in the small infarct cohort (14.2±2.6 vs. 22.9±3.0 pg; P=0.0102) and the large infarct/epilepsy cohort (10.5±2.3 vs. 18.0±3.6 pg; P=0.0462). These findings suggest that large photothrombotic infarcts of the neocortex can result in a long-lasting differential expression of GABA A receptor subunit mRNAs in ipsilateral cortex variably associated with the epileptic state.