Akt activator SC79 prevents impaired subsequent LTP in the hippocampus of hypothyroid rats.

Abstract

This study, investigated whether impaired hippocampal subsequent LTP due to hypothyroidism could be prevented by the Akt activator SC79. Hypothyroidism was induced by PTU (% 0.05) by giving it in drinking water for 21 days. Hippocampal subsequent LTP was induced by HFS (4 × 100 Hz) followed by LFS (5 Hz, 900 pulses, three min.). SC79 or saline was infused intrahippocampally for one hour, starting from induction of subsequent LTP. LTP was evaluated as field excitatory postsynaptic potential (fEPSP) slope and population spike (PS) amplitude. It was found that both the fEPSP slope and PS amplitude of the hypothyroid group rats were significantly reduced compared to the control, control + SC79, and hypothyroidism + SC79 infusion group rats. These findings indicate that hypothyroidism reduces hippocampal subsequent LTP in young-adult rats, while the infusion of the Akt activator SC79 prevents this decrease. Thus, decreased activation of Akt is responsible for the impaired hippocampal subsequent LTP in hypothyroidism.