OPRK1 and Alzheimer disease: Furthermore, in a diphenylcyclopropenone-induced model of AD, R7bp−/− mice showed diminished scratching behavior and enhanced sensitivity to the intraperitoneally applied KOR agonist U50488 (0.25 mg/kg), and the effects were most likely coupled with the activation of a KOR+ anti-pruritic neuron population in the spinal cord [208].