High-Fructose Diet-Induced Neuronal Plasticity in Rats: Implications for Acetylcholinergic Pathology and Therapeutic Approaches

Galantamine, a centrally-acting acetylcholinesterase (AChE) inhibitor, is currently used as a first-line therapy for the symptomatic treatment of Alzheimer's disease. Long-term consumption of sugar-rich beverages has been shown to be associated with the development of various clinical conditions, including metabolic syndrome, impaired cholinergic transmission, and cognitive decline. The aim of this study was to determine the effect of long-term fructose consumption on changes in short-term plasticity (STP) parameters of rat brain lateral entorhinal cortex (lEC) neurons during high-frequency stimulation (HFS) of the cholinergic nucleus basalis magnocellularis (NBM) and to evaluate the therapeutic potential of Galantamine in neurodegeneration induced by diabetes. Using the method of determining AChE activity in brain slices from intact rats exposed to Galantamine, we revealed that AChE activity showed a declining trend in the NBM and lEC. Our findings indicated that STP changes were observed in the fructose group and were associated with degenerative disorders. Specifically, there was a dramatic decrease in the proportion and intensity of excitatory responses during HFS as well as a significant increase in the mean frequency of background spike activity in neuronal populations with all response types. Galantamine resulted in a recovery tendency for the balance and intensity of excitatory and inhibitory responses. A characteristic feature of the therapeutic effect of Galantamine is an increase in the share and expression of responses in the neuronal population, exhibiting tetanic depression and post-tetanic potentiation to NBM stimulation. This clearly indicates that these neurons play a key role in homeostatic plasticity and integration into neuronal chains of cholinergic projections.