Limbic regions of the brain of Alzheimer's disease patients show selective changes in mu, delta and kappa opioid receptor binding.

Total opioid binding and levels of the three major types of opioid binding sites were measured in homogenates of various limbic structures from post-mortem brains of Alzheimer's Disease (AD) patients and age-matched control individuals. AD brains showed an increase in kappa binding in all six areas of the limbic system examined, with the putamen and caudate regions showing significant increases of 114% and 53%, respectively. In addition, the AD putamen showed a significantly higher level of total binding (85% increase). The amygdala of AD patients exhibited significantly lower levels of mu and delta binding (41% and 55% decrease, respectively).