mrk-016 and Body-Weight

Alzheimer's disease is marked by the presence of amyloid-beta (Aβ) plaques, elevated central cytokine levels, dysregulation of BDNF-related gene expression, and cognitive decline. Previously, our laboratory has demonstrated that repeated administration of peripheral LPS is sufficient to significantly increase the presence of central Aβ in the hippocampus, and that this upregulation corresponds with deficits in learning and memory. We have also previously demonstrated that the inverse benzodiazepine agonist MRK-016 (MRK) can protect against memory acquisition and consolidation errors in mice. To extend these findings, the current study explored the protective effects of MRK in the context of LPS-induced hippocampal Aβ accumulation. Hippocampal Aβ was significantly elevated, relative to saline-treated animals, following seven days of peripheral LPS injections. Animals were then trained in a contextual fear conditioning paradigm and were immediately treated with MRK or saline once training was complete. Behavioral testing occurred the day after training. Results from this study demonstrate that repeated injections of LPS significantly elevate hippocampal Aβ, and inhibit acquisition of contextual fear. Post-training treatment with MRK restored behavioral expression of fear in LPS-treated animals, despite elevated hippocampal Aβ, an effect that may be attributed to increased BDNF mRNA expression. Therefore, our data indicate that MRK can prevent LPS- induced cognitive deficits associated with elevated Aβ, and restore hippocampal BDNF expression.

Topics: Amyloid beta-Peptides; Animals; Body Weight; Brain-Derived Neurotrophic Factor; Cognition Disorders; Conditioning, Psychological; Fear; GABA Agonists; Gene Expression Regulation; Hippocampus; Isoxazoles; Lipopolysaccharides; Male; Membrane Glycoproteins; Memory; Mice; Mice, Inbred C57BL; Nuclear Receptor Subfamily 4, Group A, Member 2; Peptide Fragments; Protein-Tyrosine Kinases; RNA, Messenger; Triazines