Insulin Signaling Failures in the Brain Linked to Alzheimer's

A study published in the Proceedings of the National Academy of Sciences shows that impaired insulin signaling in the brain adversely affects cognition, mood, and metabolism, reports Medical Xpress . The investigators used a mouse model in which the expression in the brain of both insulin receptors and the insulin-like growth factor (IGF1) receptors to two regions critical for learning, memory, and mood was inhibited. "Disrupting these two signaling pathways, even with no other defects, was enough to impair learning and memory," says Harvard Medical School Professor C. Ronald Kahn. "Since these two receptors can partially compensate for one another, what we did that was critical was this combined insulin and IGF receptor knockout. However, it was also important to do it in specific regions, since if it was everywhere it might have impaired brain development. By knocking out both receptors, we removed not only the primary way they work but the backup system that's already built in." The signal disruption focused on the hippocampus and the central amygdala. Mice with both of these receptors blocked exhibited effects on both systems, including control of blood glucose, anxiety and depression, and deteriorating cognition. Such defects echo cognition impairments associated with Alzheimer's.