Decreased GABA(B)R expression and increased neuronal cell death in developing rat brain after PTZ-induced seizure

Abstract

The objective of this study was to evaluate the PTZ-induced seizures effects on GABA(B) receptor (R) expression and to observe its neurodegenerative effect in hippocampal part of developing rat brain. In the present study, high dose of pentylenetetrazol (PTZ 40 mg/kg) was injected in developing rats of age 5 weeks having average weight of 60-65 g for 4 days. Further, baclofen (B 3 mg/kg i.p) agonist and phaclofen (P 30 mu g/rat) antagonist of GABA(B)R were injected along with PTZ. Western blot analysis was used to elucidate expression of GABA(B)R protein upon PTZ, baclofen and phaclofen exposure in the developing rat brain. Furthermore, PTZ-induced apoptotic neurodegeneration was also observed through the release of caspase-3 antibody and propidium iodide (PI) staining using confocal microscopy. Seizure was confirmed using electroencephalography (EEG) data obtained from the Laxtha EEG-monitoring device in the EEG recording room and EEG was monitored 5-15 min after PTZ injection. The results of the present study showed that PTZ-induced seizure significantly decreased GABA(B)R expression and induced neuronal apoptosis in cortical and hippocampal part of brain. While, baclofen reverse the effect of PTZ by increasing the expression of GABA(B)R as compared to the PTZ- , PTZ plus B- and PTZ plus P-treated groups. Our findings indicated that PTZ-induced seizure showed not only decrease in GABA(B)R expression but also cause neuronal apoptosis in the developing rat brain.