Date palm spathe extract reverses chronic stress-induced changes in dendritic arborization in the amygdala and impairment of hippocampal long-term potentiation

Chronic restraint stress induces anxiety-like behaviors and emotional abnormalities via an alteration of synaptic remodeling in the amygdala and the hippocampus. Given that the date palm spathe has been shown to have neuroprotective effects on different experimental models, this study aimed to address whether the date palm spathe extract (hydroalcoholic extract of date palm spathe [HEDPP]) can reduce chronic restraint stress-induced behavioral, electrophysiological, and morphological changes in the rat model. Thirty-two male Wistar rats (weight 200-220 g) were randomly divided into control, stress, HEDPP, and stress + HEDPP for 14 days. Animals were submitted to restraint stress for 2 h per day for 14 consecutive days. The animals of the HEDPP and stress + HEDPP groups were supplemented with HEDPP (125 mg/kg) during these 14 days, 30 min before being placed in the restraint stress tube. We used passive avoidance, open-field test, and field potential recording to assess emotional memory, anxiety-like behavioral and long-term potentiation in the CA1 region of the hippocampus, respectively. Moreover, Golgi-Cox staining was used to investigate the amygdala neuron dendritic arborization. Results showed that stress induction was associated with behavioral changes (anxiety-like behavioral and emotional memory impairment), and the administration of HEDPP effectively normalized these deficits. HEDPP remarkably amplified the slope and amplitude of mean-field excitatory postsynaptic potentials (fEPSPs) in the CA1 area of the hippocampus in stressed rats. Chronic restraint stress significantly decreased the dendritic arborization in the central and basolateral nucleus of the amygdala neuron. HEDPP suppressed this stress effect in the central nucleus of the amygdala. Our findings indicated that HEDPP administration improves stress-induced learning impairment and memory and anxiety-like behaviors by preventing adverse effects on synaptic plasticity in the hippocampus and amygdala.