IDO1 and Alzheimer disease: In a mouse model of AD induced by intracerebroventricular Aβ1-42 administration, eight weeks of swimming training prevented memory deficits, anxiety- and depressive-like behaviors, and neuroinflammation, while blocking Aβ1-42–induced increases in IDO activity, TRP and KYN levels, and the KYN/TRP ratio in the prefrontal cortex and hippocampus, demonstrating that exercise attenuates AD-related neuropathology partly through suppressing the neurotoxic activation of the KP [92].