GABA(B(1)) splice variant mRNAs are differentially affected by electroshock induced seizure in rats

Receptor autoradiography with the high affinity antagonist radioligand [3H]CGP62349 and in situ hybridization with radiolabelled oligonucleotides were used to investigate GABA(B) receptor protein expression, and GABA(B(1)) mRNA splice variant (GABA(B(1a)) and GABA(B(1b)) levels, in brain sections from rats 4 h following a single electroshock-induced generalized seizure. Densitometric analysis indicated that GABA(B(1a)) mRNA levels were not significantly altered by an acute electroshock seizure, but that GABA(B(1b)) mRNA levels were significantly increased throughout the brain. GABA(B) receptor expression at this time point was unaffected by the seizure. The observed up-regulation of GABA(B(1b)) mRNA levels may imply increased importance of this splice variant in the regulation of further seizure activity.