Huprine X and Huperzine A Improve Cognition and Regulate Some Neurochemical Processes Related with Alzheimer’s Disease in Triple Transgenic Mice (3xTg-AD)

<b><i>Background:</i></b> Different studies have established that cholinergic neurodegeneration could be a major pathological feature of Alzheimer’s disease (AD). Thus, enhancement of the central cholinergic neurotransmission has been regarded as one of the most promising strategies for the symptomatic treatment of AD, mainly by means of reversible acetylcholinesterase inhibitors (AChEIs). The cognitive-enhancing properties of both huprine X, a new AChEI, and the structurally related huperzine A, as well as their effects on the regulation of several neurochemical processes related to AD have been studied in triple transgenic mice (3xTg-AD). <b><i>Methods:</i></b> Seven-month-old homozygous 3xTg-AD male mice, which received chronic intraperitoneal treatment with either saline, huprine X (0.12 µmol·kg^–1) or huperzine A (0.8 µmol·kg^–1) were subjected to a battery of behavioural tests after 3 weeks of treatment and thereafter the brains were dissected to study the neurochemical effects induced by the two AChEIs. <b><i>Results:</i></b> Treatments with huprine X and huperzine A improved learning and memory in the Morris water maze and some indicators of emotionality without inducing important adverse effects. Moreover, huprine X and huperzine A activate protein kinase C/mitogen-activated protein kinase pathway signalling, α-secretases (ADAM 10 and TACE) and increase the fraction of phospho-glycogen synthase kinase 3-β. <b><i>Conclusion:</i></b> Results obtained herein using a sample of 3xTg-AD animals strongly suggest that the treatment with the two AChEIs not only improves the cognitive performance of the animals but also induces some neurochemical changes that could contribute to the beneficial effects observed.