Chemogenetic Stimulation of the Dorsal Motor Nucleus of the Vagus Mitigates Autonomic Dysfunction and Memory Decline in Rat Model of Alzheimer‐Like Disease

AIM: To test the hypothesis that Alzheimer-like metabolic neurodegeneration rat model leads to an autonomic dysfunction, memory impairment, and hippocampal amyloid pathology and that long-term chemogenetic stimulation of the dorsal motor nucleus of the vagus reverses these alterations. METHODS: Male and female transgenic Long Evans rats received intracerebroventricular streptozotocin to induce sporadic Alzheimer-like pathology. Cardiovascular parameters and sympathetic and parasympathetic tone were evaluated in conscious animals. Episodic-like memory was assessed using the novel object recognition test. Hippocampal amyloid density was quantified by immunofluorescence. In male rats, cholinergic neurons of the dorsal motor nucleus of the vagus were selectively activated for 15 days using a chemogenetic approach, and autonomic, cognitive, and neuropathological outcomes were reassessed. RESULTS: In male rats, the intracerebroventricular streptozotocin induced a significant increase in cardiac sympathetic tone, reduced object discrimination index performance, and increased hippocampal amyloid density compared with vehicle-treated controls, without altering mean arterial pressure or heart rate. Female rats showed no significant autonomic, memory, or hippocampal alterations at the same time point. Long-term chemogenetic stimulation of cholinergic neurons in the dorsal motor nucleus of the vagus in male rats reduced sympathetic tone to control levels, improved recognition memory, and attenuated hippocampal amyloid density compared with the non-stimulated control group. CONCLUSION: These findings demonstrate a link between autonomic imbalance, memory dysfunction, and hippocampal amyloid pathology, and selective stimulation of the dorsal motor nucleus of the vagus restores autonomic balance and improves episodic-like memory and neuropathological outcomes, identifying this brainstem nucleus as a physiologically relevant therapeutic target in Alzheimer-related neuropathology.