Bromelain-digested casein peptide pool ameliorates chronic stress-induced impairments in hippocampal long-term potentiation and synaptic plasticity in rats.

This study examined the protective effects of bromelain-digested casein peptide pool (BDCPP) on chronic stress-induced impairments in hippocampal long-term potentiation (LTP) and synaptic plasticity in rats. Animals were randomly assigned to six treatment groups, including stressed and non-stressed controls receiving saline, casein, or BDCPP (100 mg/kg, gavage). Chronic stress was induced by daily restraint for two weeks. Electrophysiological recordings were obtained from the perforant path (PP) and dentate gyrus (DG) to evaluate baseline synaptic activity, input/output I/O curves, population spike (PS), and field excitatory postsynaptic potential (fEPSP) before and after long-term potentiation (LTP) induction. The results demonstrated that chronic stress significantly reduced population spike (PS) amplitudes across multiple stimulation intensities (I/O) after LTP. In addition, stressed animals exhibited marked decreases in the mean of both PS and field excitatory postsynaptic fEPSP values during 120 minutes following LTP induction. Treatment with BDCPP effectively mitigated these deficits, enhancing PS responses across stimulation intensities after LTP induction and improving the means of both PS and fEPSP measures at 120 minutes post-LTP. The findings of this study indicate that BDCPP enhances LTP induction, increases both PS and fEPSP responses, and ultimately attenuates synaptic plasticity impaired by chronic stress.