Davunetide improves spatial learning and memory in Alzheimer's disease-associated rats

Memory loss and cognition decline are the main clinical manifestations of Alzheimer's disease (AD). Amyloid beta protein (A beta) aggregated in the brain is one of the key pathological characteristics of AD and responsible for the deficits in learning and memory. It is reported that davunetide, an octapeptide derived from activity dependent neuroprotective protein (ADNP), inhibited A beta aggregation and A beta-induced neurotoxicity. To further characterize the neuroprotective roles of davunetide and its possible mechanism, the present study investigated the effects of davunetide on A beta 1-42-induced impairments in spatial memory, synaptic plasticity and hippocampal AICT level. In Morris water maze (MWM) test, bilateral intrahippocampal injection of A beta 1-42 significantly increased escape latency and decreased target quadrant swimming time of rats, while three weeks of intranasal application of davunetide reversed the A beta 1-42-induced learning deficits and memory loss in a dose dependent manner. In vivo field potentiation recording showed that A beta 1-42 suppressed long-term potentiation (LTP) of excitatory postsynaptic potential (IEPSP) in the hippocampal CAl region of rats, while davunetide effectively blocked the suppression of LTP, without affecting paired-pulse facilitation (PPF). Western blotting experiments showed a significant decrease in the level of hippocampal p-AICT (Ser473), not total AKT, in AS1-42 only group, which was mostly antagonized by davunetide treatment. These findings demonstrate that davunetide, probably by enhancing PI3K/AKT pathway, plays an important positive role in attenuating A beta 1-42-induced impairments in spatial memory and synaptic plasticity, suggesting that davunetide could be an effective therapeutic candidate for the prevention and treatment of neurodegenerative disease such as AD. (C) 2017 Elsevier Inc. All rights reserved.