Neuropeptide-Y both Improves and Impairs Delayed Matching-to-Sample Performancein Rats

摘要

There is increasing clinical and experimental evidence that neuropeptide-Y (NPY),a 26-amino-acid sequence reported to be one of the most prevalent neuropeptides in the brain, plays an important role in modulation of memory. Clinically, the finding of reduced NPY immunoreactivity in the cortex and hippocampus of patients with Alzheimer's disease as well as the presence of NPY-like immunoreactivity in neuronal plaques has implicated has implicated NPY in the pathogenesis of senile dementia of the Alzheimer's type. Experimentally, posttraining administration of NPY has been shown to enhance retention for both active and passive avoidance in mice. Administration of NPY prior to a retention test improves recall in mice, and NPY reverses amnesia induced by scopolamine or anisomysin. NPY administered directly into the forebrain hippocampal formation selectively enhances or impairs retention, depending upon the location of injection within rostral or caudal portions of the hippocampus.