Teucrium Polium ameliorates amyloid β-induced brain network disorders in rats: electrophysiological and behavioral studies

Synaptic failure in specific cholinergic networks in rat brains has been implicated in amyloid β-induced neurodegeneration. Teucrium polium is a promising candidate for drug development against Alzheimer's disease (AD) and similar disorders. However, the protective effect of Teucrium polium against amyloid β-induced impairment of short-term synaptic plasticity is still poorly understood. In this study, we used in vivo extracellular single-unit recordings to investigate the preventive efficacy of Teucrium polium on Aβ(25-35)-induced aberrant neuronal activity in the hippocampus and basolateral amygdala of rats, in response to high-frequency stimulation of the cholinergic nucleus basalis magnocellularis (NBM). After 12 weeks of intracerebroventricular administration of Aβ(25-35), alterations such as decreased excitatory responses and increased inhibitory synaptic activity were observed in the NBM-hippocampus and NBM-basolateral amygdala cholinergic circuits. Treatment with Teucrium polium improved the balance of excitatory and inhibitory responses by modulating synaptic transmission strength and restoring short-term plasticity. Acute injection of a therapeutic dose of Teucrium temporarily inhibited spiking activity in single NBM neurons. Open field tests revealed that amyloid-injected rats displayed anxiety and reduced exploratory drive. Treatment with Teucrium polium improved these behaviors, reducing anxiety and increasing exploration. Teucrium polium mitigated amyloid β-induced alterations in cholinergic circuits by enhancing the adaptive capacity of short-term synaptic plasticity. These findings suggest that Teucrium polium could serve as a preventive strategy to delay the progression of cholinergic neurodegeneration.